20101121 - Common Tasks for iPhone

Comments: Below are the common tasks of iPhone as defined by Apple Inc. It is important to understand these before going to Design Guidelines. Chapter 4 Handling Common Tasks 45 Starting 45 Stopping 46 Accommodating Multitasking 46 Hosting Ads 48 Managing Settings or Configuration Options 50 Supporting Copy and Paste 51 Supporting Undo and Redo 52 Enabling Local and Push Notifications 53 Making Your Application Accessible 56 Providing Search and Displaying Search Results 56 Using the User's Location 57 Handling Orientation Changes 58 Using Sound 58 The Ring/Silent Switch—What Users Expect 59 Volume Buttons—What Users Expect 59 Headsets and Headphones—What Users Expect 60 Wireless Audio—What Users Expect 60 Define the Audio Behavior of Your Application 60 Manage Audio Interruptions 64 Handle Media Remote Control Events, if Appropriate 66 Providing Choices 66 Providing a License Agreement or a Disclaimer 67 Starting iPhone applications should start instantly so users can begin using them without delay. When starting, iPhone applications should: ■ Specify the appropriate status bar style. ■ Display a launch image that closely resembles the first screen of the application. This decreases the perceived launch time of your application. ■ Avoid displaying an About window, a splash screen, or providing any other type of startup experience that prevents people from using your application immediately. ■ By default, launch in portrait orientation. However, if your application runs only in landscape orientation, your application should launch in landscape regardless of the current device orientation. This signals users to rotate the device to landscape orientation if necessary. ■ Restore state from the last time your application ran. People should not have to remember the steps they took to reach their previous location in your application. Comments: That's why almost all mobile phones have a Starting animation to hide the fact that the phone does take some time for the process of starting up. Stopping People quit an iPhone application by opening a different application. In particular, note that people don't tap an application close button or choose Quit from a menu. In iOS 4.0 and later, and on certain devices, the quitting application moves to a suspended state in the background. All iPhone applications should: ■ Be prepared to quit at any time. Therefore, save user data as soon as possible and as often as reasonable. ■ Save the current state when stopping, at the finest level of detail possible. For example, if your application displays scrolling data, save the current scroll position. Comments: Auto saving of data at appropriate frequency is important. iPhone applications should never quit programmatically because doing so looks like a crash to the user. There may be times, however, when external circumstances prevent your application from functioning as intended. The best way to handle this is to display an attractive screen that describes the problem and suggests how users can correct it. This helps users in two ways: ■ It provides feedback that reassures users that there's nothing wrong with your application ■ It puts users in control, letting them decide whether they want to take corrective action and continue using your application or press the Home button and open a different application If certain circumstances prevent only some of your application's features from working, you can display either a screen or an alert when users activate the feature. Although an alert doesn't allow much flexibility in design, it can be a good choice if you can: ■ Describe the situation very succinctly ■ Supply a button that performs a corrective action ■ Display the alert only when users try to access the feature that isn't functioning Comments: Three types of stopping: (1) User exits the application; (2) Application quits due to certain reasons; (3) Certain features of the application does not functions. Accommodating Multitasking Thriving in a multitasking environment hinges on achieving a harmonious coexistence with other applications on the device. At a high level, this means that all applications should: ■ Handle interruptions or audio from other applications gracefully ■ Stop and restart (that is, transition to and from the background) quickly and smoothly ■ Behave responsibly when not in the foreground The following specific guidelines help your application succeed in the multitasking environment introduced in iOS 4.0: ■ Be prepared for interruptions, and be ready to resume. Multitasking increases the probability that a background application will interrupt your application. Other features, such as the presence of ads and faster application-switching, can also cause more frequent interruptions. The more quickly and precisely you can save the current state of your application, the faster people can relaunch it and continue from where they left off. ■ Make sure your UI can handle the double-high status bar. The double-high status bar appears during events such as in-progress phone calls, audio recording, and tethering. In unprepared applications the extra height of this bar can cause layout problems. For example, the UI can become pushed down or covered. In a multitasking environment, it's especially important to be able to handle the double-high status bar properly because there are likely to be more applications that can cause it to appear. ■ Be ready to pause activities that require people's attention or active participation. For example, if your application is a game or a media-viewing application, make sure your users don't miss any content or events when they switch away from your application. When people switch back to a game or media viewer, they want to continue the experience as if they'd never left it. ■ Ensure that your audio behaves appropriately. Multitasking makes it more likely that other media activity is occurring while your application is running. It also makes it more likely that your audio will have to pause and resume to handle interruptions. ■ Use local notifications sparingly. An application can arrange for local notifications to be sent at specific times, whether the application is suspended, running in the background, or not running at all. For the best user experience, avoid pestering people with too many notifications. ■ When appropriate, finish user-initiated tasks in the background. When people initiate a task, they usually expect it to finish even if they switch away from your application. If your application is in the middle of performing a user-initiated task that does not require additional user interaction, you should complete it in the background before suspending. Source: Apple Inc (2001). iPhone Human Interface Guidelines: User Experience. Apple Inc, Cupertino, California.