出自UXGuide.net

停止

Stopping

iPhone applications stop when users open a different application or use a device feature, such as the phone. In particular, note that users don’t tap an application close button or select Quit from a menu. iPhone applications should:

当用户打开另外一个应用程序或设备级功能，如电话时，当前的 iPhone 应用程序将停止。特别一点的是：用户无需通过点击关闭按钮，或从菜单中选择退出。 iPhone应用程序应：

• Be prepared to receive an exit or terminate notification at any time. Therefore, save user data as soon as possible and as often as reasonable.

随时准备好接收退出或结束的通知。因此，尽快和尽可能频繁地合理保存用户的数据。

• 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.

在停止时应尽可能全面的保存当前状态。例如，若你的应用程序正在显示滚动的数据，（在停止时，）保存当前滚动的位置。

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:

iPhone应用程式永不应该程序化的退出，因为这样用户会以为是程序崩溃了。但有的时侯，外部环境阻止您的应用程序的发挥预定的功能。最好的处理办法是，显示一个有吸引力的屏幕，描述问题，并建议用户应当如何纠正它。这对用户有两个好处：

• It provides feedback that reassures users that there’s nothing wrong with your application

它提供的反馈，能让用户放心地知道你的应用程序并没有出错。

• 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

它把控制权交予用户，让他们决定是采取纠正措施，并继续使用你的应用程序还是按下主页按钮，并打开另外一个应用程序。

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:

若在某些特定情况下应用程序的部分功能无法工作，当用户触动该功能时, 你可以提供显示一个屏幕或警告。尽管在警告在设计上缺乏灵活性，但你若按下面的方法,不失为一个好的的选择：

• Describe the situation very succinctly

简洁的描述一下当前情况。

• Supply a button that performs a corrective action

提供一个可以执行纠正操作的按钮。

• Display the alert only when users try to access the feature that isn’t functioning

仅当用户尝试使用那些无法运行的功能时，才显示警告。

As with all alerts, the less users see them, the more effective they are. See “Using Alerts” for more information about creating alerts.

对于所有的警告, 越少显示他们，他们也就越有效。有关创建警告的更多信息, 请参阅“使用警告”。