[移动开发]Android ActivityLifecycleCallbacks

android-30

????ActivityLifecycleCallbacks 是 Application 的一个接口；

????Activity 的生命周期，对应 ActivityLifecycleCallbacks 中的方法；

????当实现ActivityLifecycleCallbacks 接口后，系统会在在调用 Activity 的方法后，再调用实现的ActivityLifecycleCallbacks 的实现方法。

    public interface ActivityLifecycleCallbacks {
        /**
         * Called when the Activity calls {@link Activity#onCreate super.onCreate()}.
         */
        void onActivityCreated(@NonNull Activity activity, @Nullable Bundle savedInstanceState);

        /**
         * Called when the Activity calls {@link Activity#onStart super.onStart()}.
         */
        void onActivityStarted(@NonNull Activity activity);

        /**
         * Called when the Activity calls {@link Activity#onResume super.onResume()}.
         */
        void onActivityResumed(@NonNull Activity activity);

        /**
         * Called when the Activity calls {@link Activity#onPause super.onPause()}.
         */
        void onActivityPaused(@NonNull Activity activity);

        /**
         * Called when the Activity calls {@link Activity#onStop super.onStop()}.
         */
        void onActivityStopped(@NonNull Activity activity);

        /**
         * Called when the Activity calls
         * {@link Activity#onSaveInstanceState super.onSaveInstanceState()}.
         */
        void onActivitySaveInstanceState(@NonNull Activity activity, @NonNull Bundle outState);

        /**
         * Called when the Activity calls {@link Activity#onDestroy super.onDestroy()}.
         */
        void onActivityDestroyed(@NonNull Activity activity);
    }

创建MyApplication

public class MyApplication extends Application implements Application.ActivityLifecycleCallbacks {
    public static final String TAG = "MyApplication";

    @Override
    public void onCreate() {
        super.onCreate();

        registerActivityLifecycleCallbacks(this);
    }

    @Override
    public void onActivityCreated(@NonNull Activity activity, @Nullable Bundle savedInstanceState) {
        Log.d(TAG, "onActivityCreated: " + activity);
    }
    @Override
    public void onActivityStarted(@NonNull Activity activity) {
        Log.d(TAG, "onActivityStarted: " + activity);
    }
    @Override
    public void onActivityResumed(@NonNull Activity activity) {
        Log.d(TAG, "onActivityResumed: " + activity);
    }
    @Override
    public void onActivityPaused(@NonNull Activity activity) {
        Log.d(TAG, "onActivityPaused: " + activity);
    }
    @Override
    public void onActivityStopped(@NonNull Activity activity) {
        Log.d(TAG, "onActivityStopped: " + activity);
    }
    @Override
    public void onActivitySaveInstanceState(@NonNull Activity activity, @NonNull Bundle outState) {
        Log.d(TAG, "onActivitySaveInstanceState: " + activity);
    }
    @Override
    public void onActivityDestroyed(@NonNull Activity activity) {
        Log.d(TAG, "onActivityDestroyed: " + activity);
    }
}

修改 AndroidManifest.xml

增加：
android:name=".MyApplication"

效果

D/MyApplication: onActivityCreated: com.example.testlifecycle.MainActivity@e9f5a06
D/MyApplication: onActivityStarted: com.example.testlifecycle.MainActivity@e9f5a06
D/MyApplication: onActivityResumed: com.example.testlifecycle.MainActivity@e9f5a06
D/MyApplication: onActivityPaused: com.example.testlifecycle.MainActivity@e9f5a06
D/MyApplication: onActivityStopped: com.example.testlifecycle.MainActivity@e9f5a06
D/MyApplication: onActivityDestroyed: com.example.testlifecycle.MainActivity@e9f5a06

好记性不如烂笔头！