ActivityLifecycleCallbacks是什么？
- Application通过此接口提供了一套回调方法，用于让开发人员对Activity的生命周期事件进行集中处理。
为什么用ActivityLifecycleCallbacks？
- 以往若需监測Activity的生命周期事件代码，你可能是这样做的。重写每个Acivity的onResume()，然后作统计和处理：
@Override protected void onResume() {super.onResume();//TODO 处理和统计代码Log.v(TAG, "onResume");Logger.v(TAG, "onResume");Logging.v(TAG, "onResume");... } - ActivityLifecycleCallbacks接口回调能够简化这一繁琐过程。在一个类中作统一处理
ActivityLifecycleCallbacks怎么用？
- android.app.Application.ActivityLifecycleCallbacks
- 要求API 14+ （Android 4.0+）
- 继承Application
public class BaseApplication extends Application - 在AndroidManifest里起用自己定义Application
<application android:name=".global.BaseApplication" -
重写Application的onCreate()方法，或在Application的无參构造方法内，调用Application.registerActivityLifecycleCallbacks()方法，并实现ActivityLifecycleCallbacks接口
public void onCreate() {super.onCreate();this.registerActivityLifecycleCallbacks(new ActivityLifecycleCallbacks() {@Overridepublic void onActivityStopped(Activity activity) {Logger.v(activity, "onActivityStopped");}@Overridepublic void onActivityStarted(Activity activity) {Logger.v(activity, "onActivityStarted");}@Overridepublic void onActivitySaveInstanceState(Activity activity, Bundle outState) {Logger.v(activity, "onActivitySaveInstanceState");}@Overridepublic void onActivityResumed(Activity activity) {Logger.v(activity, "onActivityResumed");}@Overridepublic void onActivityPaused(Activity activity) {Logger.v(activity, "onActivityPaused");}@Overridepublic void onActivityDestroyed(Activity activity) {Logger.v(activity, "onActivityDestroyed");}@Overridepublic void onActivityCreated(Activity activity, Bundle savedInstanceState) {Logger.v(activity, "onActivityCreated");}}); }; -
执行结果(Logcat日志)
10-21 14:32:57.722: V/WelcomeActivity(8085): onActivityCreated 10-21 14:32:57.762: V/WelcomeActivity(8085): onActivityStarted 10-21 14:32:57.762: V/WelcomeActivity(8085): onActivityResumed 10-21 14:32:59.164: V/WelcomeActivity(8085): onActivityPaused 10-21 14:32:59.194: V/MainActivity(8085): onActivityCreated 10-21 14:32:59.224: V/MainActivity(8085): onActivityStarted 10-21 14:32:59.224: V/MainActivity(8085): onActivityResumed 10-21 14:32:59.735: V/WelcomeActivity(8085): onActivityStopped 10-21 14:32:59.735: V/WelcomeActivity(8085): onActivityDestroyed 10-21 14:33:06.502: V/MainActivity(8085): onActivityPaused 10-21 14:33:06.612: V/MainActivity(8085): onActivityStopped 10-21 14:33:06.612: V/MainActivity(8085): onActivityDestroyed
ActivityLifecycleCallbacks的拓展使用方法
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本次初探仅尝试使用Log日志工具作简要測试。如需满足较复杂的统计或调试需求时。此法可能会大大降低插入代码量，提高效率
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API仅在14+版本号上提供此接口回调，Android 4.0下面系统怎样使用？
- API仅针对上述几个Activity的生命周期事件留出了接口回调，可能已无法满足日益过渡为使用Fragment的今日需求。 怎样在更大范围内应用LifecycleCallbacks？