Fluent Essays

See how to create an example web service in Android. Page 174,   Chapter 6   Getting Started with Android - Alternative Formats See how to create an example web service in iOS. Page 214,   Chapter 7   Getting Started with iOS - Alternative Formats For submission : Read carefully about 2 different approaches for creating a web service from above. Then (a) compare the two approaches and (b) explain 2 advantages of each approach relative to the other. Getting Started with Android WHAT’S IN THIS CHAPTER? ! Deciding to target Android as your mobile platform ! Getting the tools you need to develop Android ! Creating a new project ! Creating the Derby project in Android Android Inc. was initially started in 2003, out of a frustration with the smartphone market as it existed at the time. It was acquired by Google in 2005. The hardware side of Android is supported by the Open Handset Alliance (OHA), which is a conglomeration of many handset manufacturers, and the software is maintained by the Android Open Source Project, which is led by Google. Android had its fi rst major release in late 2008; the fi rst major phone company to support it was T-Mobile, and the original handset was the HTC Dream (G1). The Android OS was built on a modifi ed Linux kernel and applications are written in Java. By using Java as the development framework for the applications, Android enables you to develop your application on all major platforms. By leveraging the Eclipse IDE, Android affords the user almost the exact same user experience for development on all major OS platforms. Additionally, when researching Android you may come across the name Dalvik. It is the virtual machine that runs on the Android device, and your applications run within it. What does this mean to developers? Because your applications run inside this virtual space, it provides a level of security to the base OS. Also, Dalvik has been designed with performance in mind. As of Android 2.2 it also provides just-in-time compilation to your apps (because Dalvik requires specially compiled .dex fi les and not just the standard .class fi les generated in a normal Java compilation). 6 c06.indd 151c06.indd 151 28/07/12 6:01 PM28/07/12 6:01 PM 152 " CHAPTER 6 GETTING STARTED WITH ANDROID WHY TARGET ANDROID? Among the many reasons to target the Android platform, fi rst and foremost is cost. On average you can get an Android smartphone for a fraction of the cost of an iPhone. They may not have commensurate features, but thrift is a major component for new smartphone buyers. Next is fl exibility. More types of Android devices are available, so if your application fi ts a specifi c niche market, there is probably a device that would support your needs already in production. At the time of writing, there are effectively two iOS devices (iPhone/iPod touch and iPad); four if you include the retina display versions, versus roughly 15 form factors to develop for. If you are already a Java developer, adding Android to your repertoire is a snap. What Java is to Android, Cocoa is to CocoaTouch and C# is to Silverlight. All of the frameworks that mobile developers use are a combination of subsets and supersets of the functionality of a given technology. Identifying an application that exists on another platform but does not yet exist on Android is another perfectly good reason to target Android. That being said, you should do some research, because if a developer has targeted iOS or BlackBerry as the primary platform, you have to assume that Android is potentially on the horizon. WHO SUPPORTS ANDROID? HTC, LG, Motorola, and Samsung are the major players in the Android smartphone market. Archos, Dell, Samsung, and Toshiba hold the largest pieces of the Android tablet market. You should note that Amazon’s Kindle Fire and Nook Color are up-and-comers and use a customized version of the Android tablet (Version 3) OS on their devices. ANDROID AS COMPETITION TO ITSELF Because Android was designed to be run on many different types of devices, created by many different manufacturers (as opposed to the closed system that Apple has maintained), it has left itself open to the will of said manufacturers. Because of the open nature of the Android OS, it is commonplace for manufacturers to create vendor-specifi c builds of Android, and when this happens you are beholden to them for OS updates. Additionally in these custom builds, vendor-specifi c limitations have arisen such as the vendor-specifi c market. You then have another hurdle to cross when releasing your application for sale to the public because some devices may not be able to purchase it because of these limitations. Another issue that has cropped up is the lack of over-the-air (OTA) distribution of OS updates by cellular carriers. Often your device is perfectly capable of running a later version of the Android software, but carriers are often slow to distribute that to their customers. Multiple Markets and Market Locks Depending on your version of Android, and depending on the manufacturer of a given device, you may fi nd yourself locked into using a vendor-specifi c Android marketplace. Additionally, application c06.indd 152c06.indd 152 28/07/12 6:01 PM28/07/12 6:01 PM Getting the Tools You Need " 153 vendors can list their application not only on Google Play or vendor-specifi c marketplaces, but also on the Amazon App Store. You often fi nd on cheap and imported Android devices a version of Google Play that is maintained by the manufacturer. They pick and choose what applications are available from the whole set in the marketplace. You should develop as you expect to be available to all Android devices; just note when purchasing large quantities for an enterprise deployment that you will have to watch out for these inconsistencies. The version of the Android SDK that you need to support depends on what devices you want to support. If you want to target most phones available right now, you should support Android 2.2 or 2.3. “Gingerbread” (2.3) is the last widely available version for those devices. The Android 3.x versions are for tablets, such as the Samsung Galaxy Tab. The Android 4.x versions are the newest, and are a combination of the Android 2.x and Android 3.x functionality meant to pull back on the version splintering seen in devices, but not many devices currently in release support it. Once you have decided on a version to deploy your application against, you need to set up your development environment. In the next section you will learn all about confi guring your IDE, Java and Android SDKs, and building emulators. GETTING THE TOOLS YOU NEED This section paraphrases the installation instructions from the Android Developer section, and we added some personal notes from our experiences. Downloading and Installing JDK The fi rst thing that you need to do to develop Android applications is to visit http://www.oracle .com/technetwork/java/javase/downloads/index.html and ensure that you have the Java JDK installed. Because so many different acronyms and versions appear on the Java download website, Figure 6-1 points you in the direction you need to get past all of the potential distractions on that site. The JDK is the Java Development Kit. You need this package to do any Java development on your machine, Android or otherwise. Be sure to look for the Java Platform, Standard Edition JDK. Downloading and Installing Eclipse After you have successfully installed the JDK, you will need a development environment. The open source IDE Eclipse is recommended by Android directly in its documentation. You are not limited only to Eclipse, but the tooling has been honed over time to be the easiest solution to FIGURE 6!1: JDK download page c06.indd 153c06.indd 153 28/07/12 6:01 PM28/07/12 6:01 PM 154 " CHAPTER 6 GETTING STARTED WITH ANDROID get up and running. Figure 6-2 shows the Eclipse download page (www.eclipse.org/downloads). Download the version of Eclipse Classic that is appropriate for your operating system. FIGURE 6!2: Eclipse download site Downloading and Installing the Android SDK After you have installed the Eclipse IDE, you need to install the Android Software Developer Kit (http://developer.android.com/sdk/index.html). This includes all the tools necessary to build Android apps, because the SDK is not built directly into Eclipse. Figure 6-3 shows the Android SDK download page; make sure to get the right version for your OS. Don’t use the installer for 64-bit Windows. Just get the zip fi le and unzip it to c:\Android. At the time of writing the installer package has diffi culty fi nding the Java SDK installed on the machine. For Mac deploy it to /android in your root volume. FIGURE 6!3: Android SDK download page c06.indd 154c06.indd 154 28/07/12 6:01 PM28/07/12 6:01 PM Getting the Tools You Need " 155 Downloading and Confi guring the Eclipse ADT Plug-in After you have installed the Android SDK you need the ADT plug-in. What this does is add the features necessary to create Android Projects (and Android Test Projects), because they are not bundled with the base Eclipse install. Additionally, the plug-in adds debugging tools to Eclipse to help during the Android development process. Figure 6-4 shows the interface for installing the ADT plug-in. You will also use this interface when upgrading ADT. The tooling generally gets a revision when a new version of the Android OS is released. FIGURE 6!4: Installing the ADT plug-in Use the Update Manager feature of your Eclipse installation to install the latest revision of ADT on your development computer. Follow these steps: 1. Start Eclipse and select Help # Install New Software. 2. Click Add in the top-right corner. 3. In the Add Repository dialog box that appears, enter ADT plug-in for the name and the following URL for the location: https://dl-ssl.google.com/android/eclipse/. 4. Click OK. If you have trouble acquiring the plug-in, try using “http” in the Location URL instead of “https” (“https” is preferred for security reasons). 5. In the Available Software dialog box, select the checkbox next to Developer Tools and click Next. c06.indd 155c06.indd 155 28/07/12 6:01 PM28/07/12 6:01 PM 156 " CHAPTER 6 GETTING STARTED WITH ANDROID 6. The next window shows a list of the tools to be downloaded. Click Next. 7. Read and accept the license agreements and then click Finish. If you get a security warning saying that the authenticity or validity of the software can’t be established, click OK. 8. When the installation completes, restart Eclipse. Once you have downloaded the ADT plug-in you need to set it up to talk to the Android SDK that you downloaded earlier. This allows Eclipse to build, run, and debug Android applications without needing to open a terminal or command shell. Figure 6-5 shows where you need to add the link to the Android SDK in the Eclipse preferences. After you’ve successfully downloaded the ADT, the next step is to modify your ADT preferences in Eclipse to point to the Android SDK directory (see Figure 6-5): 1. Select Window # Preferences to open the Preferences panel. In Mac OS X, click Eclipse # Preferences. 2. Select Android from the left panel. 3. You may see a dialog box asking whether you want to send usage statistics to Google. If so, make your choice and click Proceed. You cannot continue with this procedure until you click Proceed. 4. For the SDK Location in the main panel, click Browse and locate your downloaded SDK directory. 5. Click Apply and then click OK. FIGURE 6!5: ADT confi guration screen c06.indd 156c06.indd 156 28/07/12 6:01 PM28/07/12 6:01 PM Getting the Tools You Need " 157 Installing Additional SDK Components The last step in preparing your development environment for Android is to download additional Android OS packages. This enables you to build applications that target that OS, and also gives you the tools you need to emulate a device running that OS on which to test all of your applications, whether or not they have been targeted to that OS version. Figure 6-6 shows just how many options you have when looking to target Android OS versions. FIGURE 6!6: Working with the SDK Manager Correctly confi guring and using this tool will ensure that you have all the latest SDKs and utilities afforded to you. Note that you will not necessarily need all of the versions of the SDKs listed in Figure 6-6; this was merely to illustrate the full breadth of your options. Loading the Android SDK Manager in Eclipse takes only a few steps: 1. Open Eclipse. 2. Select Window # Android SDK and AVD Manager. c06.indd 157c06.indd 157 28/07/12 6:01 PM28/07/12 6:01 PM 158 " CHAPTER 6 GETTING STARTED WITH ANDROID 3. Select Available Packages in the left panel. This reveals all of the components that are cur- rently available for download from the SDK repository. 4. Select the component(s) you’d like to install and click Install Selected. 5. Verify and accept the components you want (ensure each one is selected with a green check- mark) and click Install. The components will now be installed into your existing Android SDK directories. I recommend that you download and install an Android 2.2.x, Android 2.3.x, and Android 3.x version. This will give you the latest two handset-specifi c versions of Android, and the current tablet version of Android. As Android 4.0 is so new, you may choose to get it, but understand that you may need to purchase a newer device to test apps targeted to that version. Development The following sections discuss the application layout and Android app development. Creating a New Project First things fi rst — you need to create a new Android project. The line highlighted in Figure 6-7 is the type of project you want. FIGURE 6!7 Creating a new Android project c06.indd 158c06.indd 158 28/07/12 6:01 PM28/07/12 6:01 PM Getting the Tools You Need " 159 First you need to name your application and add it to a workspace. Think of a workspace as the folder in which your application resides. Figure 6-8 illustrates what the New Android Project screen looks like. After you have named your application you will need to give it a package name, set the minimum SDK required to run your application, and name the initial Activity that will run when your application runs. If you want to add a test project to your workspace, you can do so at this time. Figure 6-9 shows a completed Application Info step in the new project wizard. An important note at this point: Make sure that your package name is unique. The standard format for package names is com.companyName.applicationName. This must be unique because that is how it is known on the Android device and in the Android Market. When you make updates you can make them only within your package name. If you change your package name there will be no upgrade path between versions. The minimum SDK required is generally set when you are leveraging a permission or piece of functionality that did not exist when the core Android version was released, or if you want to target a specifi c type of device (tablet versus handset). The major jumps are between 1.6 and 2.1, 2.3 and 3.x, and 3.x and 4.x. Figure 6-10 shows you all of the SDKs that you have installed that you can target when creating your application. Please note that the reason this screen is full of SDKs is because I took the time to download them all for demonstration purposes. FIGURE 6!8: Naming your project FIGURE 6!9: Confi guring application information c06.indd 159c06.indd 159 28/07/12 6:01 PM28/07/12 6:01 PM 160 " CHAPTER 6 GETTING STARTED WITH ANDROID This step is also very important when building your application. The minimum SDK version you set specifi es the lowest possible version of the SDK in which your application will run, and it is the primary version in which your application will run. Android 1.5 is the lowest version of the SDK still supported, and Android 4.0.3 (at the time of this writing) is the highest. FIGURE 6!10: Choosing the SDK version for your app Figure 6-10 shows a Google version of the SDK alongside all of the versions I have installed on my machine. The Google APIs add additional functionality to each API Level. Please use your best judgment when deciding whether to use the Google APIs, and research if you need the functionality they provide. Project Structure The major sections to note in Figure 6-11 are the src and res folders and the AndroidManifest .xml fi le. It shows the project layout for the application that I have been building in the previous steps. c06.indd 160c06.indd 160 28/07/12 6:01 PM28/07/12 6:01 PM Getting the Tools You Need " 161 All of your code lives within your src folder, under your Package Namespace. The res folder holds layouts and resources for different hardware specs. HDPI, LDPI, and MDPI are the resolutions for which you can create images. The layout subfolder holds all of your XML layouts. These are how your application gets rendered. The code will be how to populate these layouts. All of your XML layouts are stored in the layout subfolder of res, and your code will be linked under the namespace in your src folder of the project view. The Android Manifest is the heart of your application. It holds the entire confi guration of your app (Figure 6-12) — the permissions you request (Figure 6-14), the application attributes (Figure 6-13), and links to instrumentation to be attached to your app. You can edit this in Eclipse’s Manifest Editor or in XML (Figure 6-15) because that is how it is saved. FIGURE 6!11: Basic project structure FIGURE 6!12: Main Manifest Editor c06.indd 161c06.indd 161 28/07/12 6:01 PM28/07/12 6:01 PM 162 " CHAPTER 6 GETTING STARTED WITH ANDROID The Manifest Editor is where the initial information of your application is stored when you create it. This interface also has links to export your application. Exporting is necessary when submitting your app to Google Play. In Eclipse there is a specifi c menu option and wizard that expedites the submission process. Figure 6-13 shows all of the base properties that can be set for a given application in the app’s AndroidManifest.xml fi le. The most common properties to edit are the Label (the text shown under the icon, often referenced in a resource fi le) and Icon (the icon shown in the launcher UI of your device, the icon your users will click on to launch the app). FIGURE 6!13: Manifest Application Info Editor The spartan view shown in Figure 6-14 is the Permissions Editor. Here you can add permission requests to your application. The most common one is android.permission.INTERNET, which allows the application to use the device Internet connectivity. This, along with GPS and accelerometer, are the permissions you will add to the Derby Names application. c06.indd 162c06.indd 162 28/07/12 6:01 PM28/07/12 6:01 PM Getting the Tools You Need " 163 Last is the XML Editor shown in Figure 6-15. As you make changes in the other tabs they are refl ected here. If you feel more comfortable editing the XML by hand you can use this interface to add, update, and remove properties as you see fi t. FIGURE 6!14: Android Manifest Permissions Editor FIGURE 6!15: Android Manifest XML Editor c06.indd 163c06.indd 163 28/07/12 6:01 PM28/07/12 6:01 PM 164 " CHAPTER 6 GETTING STARTED WITH ANDROID Android Basics You have two options for starting your application. You can build the layout you would like to populate, or you can build the code that will populate the layout. Either is acceptable; it just depends on what you feel most comfortable with. Creating User Interfaces This section describes the common widgets that come with Android, and shows examples of the different layout elements you can use to coordinate the fl ow of your application’s activities. Basic Android UI Elements All of the basic elements in Android are stored in the android.widgets namespace in the SDK. The most commonly used elements include: ! Button: This is a standard button element. The following XML specifi es the layout of the Button widget: <Button android:layout_height=”wrap_content” android:layout_width=”wrap_content” android:id=”@+id/button” android:text=”Click Me” android:onClick=”btnClick” /> Code: This code is necessary to handle the Click event noted in the XML layout. public void btnClick (View view) { //Do Something. } ! TextView: When I see this I want to think text box, but it isn’t a text box. TextView is effectively the same as a label in other languages. It is just a place to display text. Layout: <TextView android:id=”@+id/textview” android:layout_width=”fill_parent” android:layout_height=”fill_parent” android:text=”Hello World”/> Code: TextView tvToShow = (TextView)this.findViewById(R.id.textview); tvToShow.setText(“Ta-Dah!”); ! EditText: This is the text box widget. You can edit the contents of the text box and save those values in code. c06.indd 164c06.indd 164 28/07/12 6:01 PM28/07/12 6:01 PM Getting the Tools You Need " 165 Layout: <EditText android:id=”@+id/txtUsername” android:hint=”Username” android:layout_width=”fill_parent” android:layout_height=”wrap_content” /> Code: EditText txtUserName = (EditText) findViewById(R.id.txtUsername); String username = txtUserName.getText().ToString(); ! CheckBox: This is a standard checkbox element. Layout: <CheckBox android:id=”@+id/checkbox” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:text=”Checkbox Text” /> Code: final CheckBox checkbox = (CheckBox) findViewById(R.id.checkbox); checkbox.setOnClickListener(new OnClickListener() { public void onClick(View v) { if (((CheckBox) v).isChecked()) { //It’s Checked } else { //Not Checked } } }); ! RadioButton: This is a standard radio button element. To really get the most bang for your buck, though, you need a RadioGroup. Layout: <RadioGroup android:layout_width=”fill_parent” android:layout_height=”wrap_content” android:orientation=”vertical”> <RadioButton android:id=”@+id/radio_uno” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:text=”1 - Uno” /> <RadioButton android:id=”@+id/radio_dos” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:text=”2 - Dos” /> </RadioGroup> c06.indd 165c06.indd 165 28/07/12 6:01 PM28/07/12 6:01 PM 166 " CHAPTER 6 GETTING STARTED WITH ANDROID Code: private OnClickListener radioButtonOnClick = new OnClickListener() { public void onClick(View v) { RadioButton rb = (RadioButton) v; // Do with it what you will //rb.getText(); } }; //This assigns this event to the radio buttons. RadioButton radio_uno = (RadioButton) findViewById(R.id.radio_uno); RadioButton radio_dos = (RadioButton) findViewById(R.id.radio_dos); radio_uno.setOnClickListener(radio_listener); radio_dos.setOnClickListener(radio_listener); Figure 6-16 shows all of the major UI widgets. ! ListView: This is the element you use if you want to show lists of data. You can overload its display and put lots of elements in each row, or you can just bind a text item and a value to each. The trick is using an ArrayAdapter<T> where T is the type of object that you want bound. Additionally, creating a layout XML for how you want each item displayed is a good strategy. Layout: <ListView android:id=”@+id/lstWords” android:layout_width=”fill_parent” android:divider=”#ddd” android:dividerHeight=”1px” android:paddingBottom=”67dp” android:layout_height=”fill_parent” /> Code: static final String[] words = new String[]{ “Hello”, “World” }; lstWords = (ListView)findViewById(R.id.lstWords); lstWords.setAdapter new ArrayAdapter<String>(this.getApplicationContext(),R.id.list_content,words)); Basic Android Layouts and Views ! FrameLayout: This is very simplistic and can really contain only a single UI element. You can, in fact, have multiple elements but they overlap each other by default. The example code shown here is rendered in Figure 6-17: FIGURE 6!16: Major UI elements all together c06.indd 166c06.indd 166 28/07/12 6:01 PM28/07/12 6:01 PM Getting the Tools You Need " 167 <?xml version=”1.0” encoding=”utf-8”?> <FrameLayout android:id=”@+id/frameLayout” android:layout_width=”fill_parent” android:layout_height=”fill_parent” xmlns:android=”http://schemas.android.com/apk/res/android”> <EditText android:id=”@+id/widget46” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:text=”EditText” android:textSize=”18sp” /> </FrameLayout> This is a simple FrameLayout that contains a single EditText widget with the text “EditText.” LinearLayout: This lays out your UI elements along a given direction: horizontal or vertical. Figure 6-18 is a linear layout, which contains four consecutive TextView widgets along the vertical. FIGURE 6!17: FrameLayout rendered FIGURE 6!18: LinearLayout rendered Example: <?xml version=”1.0” encoding=”utf-8”?> <LinearLayout android:id=”@+id/widget59” android:layout_width=”fill_parent” android:layout_height=”fill_parent” android:orientation=”vertical” xmlns:android=”http://schemas.android.com/apk/res/android”> c06.indd 167c06.indd 167 28/07/12 6:01 PM28/07/12 6:01 PM 168 " CHAPTER 6 GETTING STARTED WITH ANDROID <TextView android:id=”@+id/widget60” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:background=”#ffaa0000” android:layout_marginTop=”5dp” android:layout_marginLeft=”5dp” android:text=”red” /> <TextView android:id=”@+id/widget63” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:background=”#ffaaaa00” android:layout_marginTop=”5dp” android:layout_marginLeft=”5dp” android:text=”yellow” /> <TextView android:id=”@+id/widget64” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:background=”#ff00aa00” android:layout_marginTop=”5dp” android:layout_marginLeft=”5dp” android:text=”green” /> <TextView android:id=”@+id/widget65” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:background=”#ff0000aa” android:layout_marginTop=”5dp” android:layout_marginLeft=”5dp” android:text=”blue” /> </LinearLayout> ! TableLayout: Think tables in HTML and this is the type of organization you get with this layout. TableLayouts contain rows and columns, representing a grid, and you can put other UI elements into it. The following code results in a table with two rows, each with two cells, and is visualized in Figure 6-19: <?xml version=”1.0” encoding=”utf-8”?> <TableLayout xmlns:android=”http://schemas.android.com/apk/res/android” android:layout_width=”fill_parent” android:layout_height=”fill_parent” android:stretchColumns=”1”> <TableRow> <TextView android:text=”Hello” android:padding=”3dip” /> <TextView android:text=”World” android:gravity=”right” android:padding=”3dip” /> </TableRow> c06.indd 168c06.indd 168 28/07/12 6:01 PM28/07/12 6:01 PM Getting the Tools You Need " 169 <TableRow> <TextView android:text=”Goodbye” android:padding=”3dip” /> <TextView android:text=”User” android:gravity=”right” android:padding=”3dip” /> </TableRow> </TableLayout> ! RelativeLayout: This is the most complex layout of the four mentioned in this section. You specify relationships between UI elements to lay out your interface. The following code represents a simple form with a TextView acting as a label for a blank EditText widget, with Cancel and OK widgets docked … Getting Started with iOS WHAT’S IN THIS CHAPTER? ! History of iOS ! Getting an iOS development setup ! Objective-C Basics ! iOS Project Basics ! Implementing the Derby App This chapter is not intended to make you an expert iOS/Objective-C/Cocoa Touch developer; it’s intended to give you an idea of what it takes to create a mobile application on the iOS platform. In our everyday interaction with developers, we have found that many developers dread learning Objective-C, the native language used to create iOS applications. At technical conferences, we have often sat in on beginning-level sessions on how to develop iOS applications, where the presenter has said, “This is very diffi cult, you don’t want to do it.” We have no idea why some of the developer community thinks this way. Code is code (unless you are working with a functional language, but that’s a topic for a different day). Learning a new programming language/framework takes time and a bit of passion — if you are reading this book, we have no doubt in our mind that you can obtain some more Objective-C resources and have what you need to become an Objective-C developer. THE IPHONE CRAZE The fi rst iPhone was revealed at the Mac World conference in early January 2007, and later released in June of that year. Initially, third-party native applications were not allowed. Apple executives argued that developers could build web (HTML/CSS) applications that would 7 c07.indd 183c07.indd 183 28/07/12 6:02 PM28/07/12 6:02 PM 184 " CHAPTER 7 GETTING STARTED WITH IOS behave like native iPhone apps. Developers pushed back, and in October 2007 Apple announced an SDK that allowed developers to create native iPhone applications. Many argue that Apple’s decision to allow developers to create native applications was based on the fact that the Android platform was going to be hitting the market soon, and was an extremely open and fl exible platform in which developers could do things that they could not within iOS. The decision to allow native apps within iOS created a new business model for developers, where small projects after work hours have turned into full-fl edged companies. As of February 2012, the Apple App Store contained more than 725,700 applications, which have collectively been downloaded more than 25 billion times. Since June 2007, iPhones have helped drive the mobile boom. Apple converted a generation of iPod users to iPhone users with simple and effective user interface practices, and made its product “cool.” In May 2010, 59 percent of all mobile web data consumption in the U.S. came from iPhones. The iPhone was a game changer: a personal organizer, gaming platform, web browser, and a phone all in one small package. Apple in Its Beauty When Steve Jobs introduced the world to the iPhone he proclaimed it as a revolutionary product that would change everything, with a brand-new “multi-touch” interface as breakthrough and as breathtaking as the mouse interface that was introduced in the 1960s. We agree with this statement, and feel that it was the iPhone that kick-started the mobile boom. The iPhone was marketed to consumers, and its ease of use made just about everybody want one. At the time of its release, the core uniqueness of the iPhone went far beyond its web browser and tightly integrated web functionality. It was six core ideas (outlined in the following list) that changed software applications and websites. Although there were “smartphones” on the market at the time of release of the iPhone, it was not until after the iPhone was released that smartphone manufacturers realized the importance of all of these features being combined to provide a great mobile development platform. Always on the Internet: A platform that had Internet access wherever cell phone coverage was available opened the door for a new type of application to be developed. Without this functionality, applications such as foursquare (an app that allows you to “check in” to locations) would not exist. This core concept is easy for developers to develop for; the most diffi cult part is coming up with an application idea. Location-aware: The iPhone also introduced a platform that could detect where you were based on your location. Apart from privacy concerns, this feature has been well received in the developer and user community. Whether it’s a mapping application or an application that lets you tag photos with your location, this feature opened tremendous opportunity for developers to develop location-based apps that did not have to run on a standalone GPS. Orientation-aware: In addition to location awareness, the iPhone offered a platform that could now detect where in space the device existed. The app that made this feature popular is Urbanspoon. Urbanspoon displays a random restaurant in your area based on criteria c07.indd 184c07.indd 184 28/07/12 6:03 PM28/07/12 6:03 PM that you set. If you do not like the restaurant that it picks, you can “shake” the phone and it will choose another one. This is a new type of UI feature that makes interfaces easier to use. The mobile gaming industry has also taken full advantage of the iPhone’s orientation awareness, releasing many games that allow you use the device as the control stick; for example, moving the iPhone left and right in a race car game makes the car turn left and right, making it feel as though you are actually using a steering wheel. Innovative input: The iPhone also represented a platform that could detect multiple fi ngers as input, as well as a wide range of gestures such as swipe up, swipe down, tap, dou- ble tap, and so on. With new input types, new UI patterns emerged helping make the small screen of the mobile device easier to deal with. High-quality, scalable screen: A huge selling point for the iPhone is its high-resolution screen on which movies and photos can be viewed with stunning picture quality. Power consciousness: Because the iPhone runs on battery, you as a developer need to watch the power consumption of your application. Loops within your code can cause the CPU to work hard, and when the CPU works hard it takes more power, causing your application to drain the device’s battery, which could result in negative comments from users. Years ago, developers worked to keep the size of applications small; for mobile development, you should pay close attention to how an application is coded, and ensure it doesn’t use too much power. Apple Devices Throughout the years, Apple has produced many different types of mobile devices. From the iPod classic to the iPhone, Apple has created great products, but has not always opened these products up for developers to create apps for or modify them. For the purpose of this chapter, we are going to discuss iPhone, iPod touch, and the iPad. Although each of these devices runs a version of iOS, it’s important to note that older devices may not be able to run the latest version of iOS. For example, if your company tasked you with creating an app for your sales department and the entire sales team had iPhone 3Gs, you could not take advantage of the great features in iOS 5.0, because these devices run only in iOS 4.2.1 and below. iPhone The iPhone may well be the reason why you are reading this book. Since its introduction in 2007, the iPhone has helped fuel the mobile boom that is currently underway. It has been the thorn in the side of many IT departments, from networking issues (employees bringing their own devices to work, which raises security concerns) to development issues (making your applications run on iOS). From 2007 to December 2011 fi ve devices have been released. It’s important to understand the close relationship between the iOS hardware and software. Meaning, not all versions of iOS will run on all iOS hardware. As device hardware becomes dated, Apple stops releasing iOS updates. Table 7-1 shows iOS hardware with the version of iOS that shipped with the device and the maximum version that can be installed on the device. The iPhone Craze " 185 c07.indd 185c07.indd 185 28/07/12 6:03 PM28/07/12 6:03 PM 186 " CHAPTER 7 GETTING STARTED WITH IOS TABLE 7!1 iPhone Hardware and iOS Versions DE VICE SHIPPE D IOS VE RSION MA X IOS VE RSION iPhone iOS 1.0 iOS 3.1.3 iPhone 3G iOS 2.0 iOS 4.2.1 iPhone 3GS iOS 3.0 iPhone 4 iOS 4.0 iPhone 4S iOS 5 iPod Touch After the release the original iPhone, Apple added a new product to the iPod product line: the iPod touch. This device was built on iPhone technology, looked identical to the iPhone, and used the same 480 ! 320 multitouch screen, but it was not a phone. This was a great option for consumers who wanted the iPhone experience, but did not want to pay the fees for a cell phone contract. Because of its lack of cellular connectivity, this device could access the Internet only through a wireless Internet connection. Table 7-2 shows iOS hardware with the version of iOS that shipped with the device and the maximum version that can be installed on the device. TABLE 7!2 iPod touch Hardware and iOS Versions DE VICE SHIPPE D IOS VE RSION MA X IOS VE RSION 1st generation iOS 1.1 iOS 3.1.3 2nd generation iOS 2.1.1 iOS 4.2.1 3rd generation iOS 3.1.1 4th generation iOS 4.1 iPad Introduced in January of 2010, the iPad was another revolutionary product from Apple. When the iPad was fi rst released, many argued it was just a big iPod touch, which was partially true. You could purchase a cellular data plan so that the device could access data but not phone service. The same great UI that made the iPhone and iPod Touch famous was now available with a 1024 ! 768 screen size. The iPad pushed the mobile boom even more, with many industries seeing the benefi t that a tablet computer could provide. With two models containing different data storage sizes and access to cellular data, the iPad is leading the way in tablet computing. Table 7-3 shows iOS hardware with the version of iOS that shipped with the device and the maximum version that can be installed on the device. c07.indd 186c07.indd 186 28/07/12 6:03 PM28/07/12 6:03 PM Getting the Tools You Need " 187 TABLE 7!3 iPad Hardware and iOS Versions DE VICE SHIPPE D IOS VE RSION MA X IOS VE RSION iPad iOS 3.2 iPad 2 iOS 4.3 iPad 3 iOS 5.1 GETTING THE TOOLS YOU NEED Developing for iOS is not a matter of opening up your favorite text editor and going to town. You may need to do a bit of planning, with the fi rst (and most expensive) being hardware. Depending on your development intentions you may need to pay Apple for the honor of being an iOS developer as well. Hardware Oftentimes we are asked, “Do I really need to have a Mac?” The answer is yes. To develop iPhone, iPod, and iPad applications you must have a Mac. The iPhone SDK runs only on Mac OS X. The only sanctioned hardware for iPhone, iPod, and iPad development is an Intel-based Macintosh. If you are having a hard time justifying the cost of the hardware, we have had great luck with getting refurbished machines direct from Apple at the following URL: http://store.apple.com/us/browse/home/specialdeals/mac Because we work in many different languages and platforms each day, all of the developers we work with have Mac computers. The developers we work with mainly in .NET like to say the Macs are the best Windows machines they have ever had. Program Levels If you do not have an Apple Developer account, you can create a free account at https:// developer.apple.com/. Having the Apple Developer account allows you to create iOS applications and run them locally on your machine using the iOS Simulator. To deploy applications you have created to a physical device (iPhone, iPad, iPod Touch) you must belong to the iOS Developer program. This is where the money comes in. These programs and prices change from time to time, so please use the following only as a guide, and check https://developer.apple.com/programs/start/ios/ before making any mission-critical decisions. iOS Developer Program This program level allows developers to distribute apps in the App Store as an individual, a sole proprietor, a company, an organization, a government entity, or an educational institution. The cost for this program is $99 a year, and you are allowed to name 100 devices within your iOS Developer account (which is covered in the device section of this chapter). c07.indd 187c07.indd 187 28/07/12 6:03 PM28/07/12 6:03 PM 188 " CHAPTER 7 GETTING STARTED WITH IOS iOS Developer Enterprise Program This program level allows developers to develop proprietary apps for internal distribution within your company, organization, government entity, or educational institution. The cost for this program is $299 a year. This level of the program will not allow you to distribute apps through the App store, but allows ad hoc distributions (distribute directly to a device without using the App Store) to devices in your organization. A valid Dun & Bradstreet (DUNS) number is required, and this program level will take a little bit longer to get enrolled in. We have seen this process take well over a month before acceptance into the program. iOS Developer University Program This program level allows higher-education institutions to create teams of up to 200 developers that can develop iOS applications. This program level is free, and allows for programs to be tested on physical devices, but does not allow for ad hoc or App Store deployment. The iOS Provisioning Portal No matter which level of Apple Developer program you registered for, you will have access to the iOS Provisioning Portal. This is the section of the iOS Developer Center that allows you to create the fi les necessary to deploy development and distribution (production) builds onto physical devices. Certifi cates During the development process of your iOS app, you will more than likely create both a development and a distribution certifi cate. These certifi cates are used to digitally sign the app, and verify you are who you say you are. Figure 7-1 shows the iOS Provisioning Portal Certifi cate section, found within the iOS developer account web interface; here both development and distribution certifi cates are created. FIGURE 7!1: iOS Provisioning Portal certifi cates c07.indd 188c07.indd 188 28/07/12 6:03 PM28/07/12 6:03 PM Getting the Tools You Need " 189 App IDs Each iOS application that you create (that you intend to deploy to a device) needs to be identifi ed on the App IDs section of the iOS Provisioning Portal. The app ID that is created is a unique ID that contains a number from Apple and then a bundle identifi er that you specify. The bundle identifi er is usually in the format com.companyname.appname. As you start to develop more applications, they tend to become messy in this interface, as shown in Figure 7-2. FIGURE 7!2: iOS Provisioning Portal App IDs Devices The Devices section in the iOS Provisioning Portal section allows developers to maintain a list of devices in which their iOS applications will be developed. These are the devices that are either used for testing your app or for ad-hoc deployments. The number of devices that you can register on this screen relates to the type of Apple Developer account level you selected. For example, if you registered at the iOS Developer level, you will be able to add 100 devices. This number is 100 per year, meaning if you add 100 devices and then delete 10, you are still out of spaces for accounts until you re-enroll in the program the following year, which will still only have a maximum of 100 devices. This can become problematic if you are developing iOS applications for multiple customers who have not set up accounts for themselves. It’s important to manage and plan ahead for the amount of devices you will need. Figure 7-3 shows that there is room for only 16 more devices in this account. c07.indd 189c07.indd 189 28/07/12 6:03 PM28/07/12 6:03 PM 190 " CHAPTER 7 GETTING STARTED WITH IOS Provisioning Files After the certifi cate, the app ID, and devices have been created/added, you can then create a provi- sioning profi le. The provisioning profi le combines the information about which apps/certifi cates can be installed on which devices. As with certifi cates there will be a Development and Distribution version. Figure 7-4 shows the Provisioning section within the iOS Provisioning Portal. FIGURE 7!3: iOS Provisioning Portal provisioning devices FIGURE 7!4: iOS Provisioning Portal Provisioning Profi le c07.indd 190c07.indd 190 28/07/12 6:03 PM28/07/12 6:03 PM Getting the Tools You Need " 191 FIGURE 7!5: iOS Dev Center With all of the Apple administrative tasks complete with regard to setting up an account and obtaining provisioning profi les and certifi cates, you can move on to installing the xCode IDE and starting to work with the iOS SDK. xCode and the iOS SDK To create native iOS applications, you will need to install both the xCode IDE as well as the iOS SDK. Although you can obtain xCode by using the App Store within Mac OS X, we recommend download- ing xCode and the SDK from the downloads section in the iOS Dev Center as shown in Figure 7-5. Installation After you follow the steps to install xCode, you should have the xCode IDE as well as a great deal of other useful development tools installed to /Developer/Applications, as shown in Figure 7-6. c07.indd 191c07.indd 191 28/07/12 6:03 PM28/07/12 6:03 PM 192 " CHAPTER 7 GETTING STARTED WITH IOS FIGURE 7!7: xCode startup screen FIGURE 7!6: Development tools You can start xCode from this directory or by using spotlight. After you start xCode, you should see a screen similar to the one shown in Figure 7-7. Components of the iPhone SDK The iPhone SDK includes a great number of tools that help create iOS for apps. These tools range from debugging and profi ling to developing. This section lists the most common tools that we use that are included in the iOS SDK. c07.indd 192c07.indd 192 28/07/12 6:03 PM28/07/12 6:03 PM iOS Project " 193 xCode xCode is Apple’s Integrated Development Environment (IDE) for creating Objective-C applications. xCode enables you to manage, author, and debug your Objective-C projects. Dashcode Dashcode is an IDE that enables you to develop web-based iPhone/iPad applications and Dashboard widgets. This product is not in the scope of this book as it is considered an advanced topic. iPhone Simulator This tool provides a method to simulate an iPhone or iPad device on your Mac, for use with testing your iOS applications. Interface Builder The Interface Builder, or IB, is a visual editor that is used for designing the user interface for your iOS application. Instruments Instruments is a suite of tools that helps you analyze your iOS application and monitor for performance bottlenecks as well as memory leaks in real time while attached to an iOS device or iOS Simulator. The iOS Human Interface Guideline The iOS Human Interface Guideline (HIG) document is one of the most valuable tools to the iOS developer. The iOS HIG describes guidelines and principles that help the iOS developer design a superlative user interface and user experience. It is very important for new iOS developers to read through this document; if you do not develop using the UI principles found in the HIG, your application could be rejected when submitted to the Apple App Store. The UI standards that Apple puts in place for developers can cause heated conversation. One side of the argument is that developers are locked into obeying a set of rules that cost time and money to learn and implement. The other side of the argument is that Apple has provided a standard UI for applications that have been created for the platform, thus giving the user a great experience no matter who creates the app. You can fi nd the iOS HIG at http://developer.apple.com/library/ios/#documentation/ UserExperience/Conceptual/MobileHIG/Introduction/Introduction.html#/apple_ref/ doc/uid/TP40006556. With the xCode IDE and iOS SDK installed, you can now examine what exactly makes up an iOS project with respect to fi les and code. IOS PROJECT By now you may be thinking that you need to follow a lot of steps before you start creating an iOS application. This may be the reason many seasoned iOS developers try to steer new developers from the platform. Although it takes a lot of steps to get going, they are not complicated or diffi cult; it’s just a matter of learning them and why they exist, which is covered in the remainder of this chapter. c07.indd 193c07.indd 193 28/07/12 6:03 PM28/07/12 6:03 PM 194 " CHAPTER 7 GETTING STARTED WITH IOS With all of the “setup” out of the way, we can focus on getting into the IDE and looking at code. Anatomy of an iOS App iOS .app fi les, the fi les that are actually deployed to the iOS device, are just a set of directories. Although there is an actual binary for the iOS application, you can open the .app fi le and fi nd the images, meta data, and any other resources that are included. Views iPhone apps are made up of one or more views. Views usually have GUI elements such as text fi elds, labels, buttons, and so on. You can build a view built using the Interface Builder tool, which enables you to drag and drop controls on the view, or you can create a view entirely with code. Code That Makes the Views Work Because iOS applications follow the MVC design pattern, there is a clean break between the UI and code that provides the application code. Resources Every iOS application contains an icon fi le, an info.plist fi le that holds information about the application itself and the binary executable. Other resources such as images, sounds, and video are also classifi ed as resources. Project Structure in Depth When an iOS project is created within xCode, the IDE creates a set of fi les that are ready to run. These fi les provide the basics of what is needed to get going with a new project. Figure 7-8 shows the fi les that are created for a new project named DeleteMe. Main.m As with any C program, the execution of Objective-C applications start from the main() function, which is the main.m fi le. AppDelegate.m The AppDelegate receives messages from the application object during the lifetime of your application. The AppDelegate is called from the operating system, and contains events such as the didFinishLaunchingWithOptions, which is an event that iOS would be interested in knowing about. MainStoryBoard.storyboard This is where the user interface is created. In past versions of xCode/iOS the user interface was stored within .xib (pronounced NIB) fi les. Although this method is still supported, Storyboards are a great improvement over .xib fi les for applications with complex navigation and many views. FIGURE 7!8: Anatomy of an iOS app c07.indd 194c07.indd 194 28/07/12 6:03 PM28/07/12 6:03 PM iOS Project " 195 FIGURE 7!9: Project Navigator Supporting Files The supporting fi les directory contains fi les such as the plist setting fi les (which contain customiz- able application settings), as well as string resource fi les that are used within your app. Getting to Know the xCode IDE It’s important to use the correct tool for the job, regardless of whether you are constructing a house or constructing an application. If you are new to xCode, there will be a bit of a learning curve to becoming profi cient with the IDE, but xCode is a top-notch IDE with many features for you to discover. Navigators The left side of the xCode window is known as the navigator area. A variety of navigators enable you to list the contents of your project, fi nd errors, search for code, and more. The remainder of this section introduces the Project Navigator, the Search Navigator, and the Issue Navigator. Going from left to right, the project navigator is the fi rst of the xCode navigators; the icon looks like a fi le folder. The Project Navigator simply shows the contents of your project or workspace, as shown in Figure 7-9. Double-clicking a fi le in the Project Navigator opens the fi le in a new window, and single-clicking opens the fi le within the xCode workspace. c07.indd 195c07.indd 195 28/07/12 6:03 PM28/07/12 6:03 PM 196 " CHAPTER 7 GETTING STARTED WITH IOS FIGURE 7!10: Search Navigator The Issue Navigator lists project warnings and errors in real time as you make mistakes. This navi- gator shows any issues preventing your code from compiling, as shown in Figure 7-11. The Search Navigator helps you locate text within your project or workspace as shown in Figure 7-10. c07.indd 196c07.indd 196 28/07/12 6:03 PM28/07/12 6:03 PM iOS Project " 197 FIGURE 7!11: Issue Navigator Storyboards In iOS versions prior to iOS 5, developers needed to create a separate XIB fi le for each view of their application. A XIB fi le is an XML representation of your controls and instance variables that get compiled into the application. Managing an application that contains more than a few views could get cumbersome. iOS 5 contained a new feature called storyboards that enables developers to lay out their workfl ow using design tools built within xCode. Apps that use navigation and tab bars to transition between views are now much easier to manage, with a visual representation of how the app will fl ow. Transitions and segues are used to switch between views, without ever having to code them by hand. c07.indd 197c07.indd 197 28/07/12 6:03 PM28/07/12 6:03 PM 198 " CHAPTER 7 GETTING STARTED WITH IOS With Storyboards, you will have a better conceptual overview of all the views in your app and the connections between them. Figure 7-12 is an example of a Storyboard for an application that contains a tab bar for navigation to three other views. Segues are the arrows that connect the views. FIGURE 7!12: Sample Storyboard c07.indd 198c07.indd 198 28/07/12 6:03 PM28/07/12 6:03 PM Debugging iOS Apps " 199 DEBUGGING IOS APPS A bug discovered in the fi eld is much more expensive to fi x than bugs that are found on a developer’s machine or during the quality assurance process. Modern-day IDEs provide a great deal of tooling that helps developers fi nd issues in their code before it reaches production. The iOS Simulator Developers use the iOS Simulator as their fi rst way of fi nding issues with the code they just created. The iOS Simulator enables developers to run their iOS applications on their Macs without having to have a physical iOS device. The Simulator is a great tool for testing your apps quickly. The iOS Simulator is very quick to load, compared to other simulation tools for other mobile platforms. The iOS Simulator is also a great tool for HTML/CSS experts to have installed as well to test mobile webpages rendered within the mobile Safari web browser. Figures 7-13 and 7-14 show the Simulator simulating an iPhone and iPad, respectively. The term “debugging” was made popular by Admiral Grace Murray Hopper, who was working on a Mark II computer at Harvard University in August 1945, when colleagues discovered a moth stuck in a relay that was causing issues with the system. She made the comment they were “debugging the system.” FIGURE 7!13: iOS Simulator simulating an iPhone FIGURE 7!14: iOS Simulator simulating an iPad c07.indd 199c07.indd 199 28/07/12 6:03 PM28/07/12 6:03 PM 200 " CHAPTER 7 GETTING STARTED WITH IOS By no means is the Simulator the only tool you should use for testing your app. Although the Simulator is great for testing some things, it lacks in other areas. Not all applications that are avail- able on a physical iOS device are available within the Simulator. Besides that, memory, performance, accelerometer, and camera functionality cannot be tested reliably in the Simulator. One nice feature of the iOS Simulator is the ability to test various iOS versions, as shown in Figure 7-15. FIGURE 7!15: iOS Simulator version options The iOS Simulator is not an emulator. An emulator tries to mimic the behavior of a real device. The iOS Simulator simulates real behavior of the iOS device, but relies on various libraries that are installed on the Mac, such as QuickTime, to perform renderings so that it looks like an actual iPhone. Applications that are deployed to the iOS Simulator are compiled to x86 code, whereas on a real iOS device the code would be compiled to ARM-based code. Debugging Code As with many modern-day IDEs, Apple and the xCode team have put a great deal of time and effort into creating a set of tools to aid developers in their quest for hunting bugs. When it boils down to it, developers want tools that make their life easier — tools to step through the code, view log messages, as well as see the state of their variables. xCode provides tools for these features, and much more. c07.indd 200c07.indd 200 28/07/12 6:03 PM28/07/12 6:03 PM Debugging iOS Apps " 201 The debugging tools within xCode are located at the bottom of the workspace window. If you do not see the debugging tools, you can click View # Debug Area # Show Debug Area from the xCode menu (see Figure 7-16) to make the …