Activitylifecyclecallbacks使用

Application通过ActivityLifecycleCallbacks使用接口提供了一套回调方法，用于让开发者对Activity的生命周期事件进行集中处理。 ActivityLifecycleCallbacks接口回调可以简化监测Activity的生命周期事件，在一个类中作统一处理。 ActivityLifecycleCallbacks使用要求API 14+ （Android 4.0+）。

使用方法

重写Application的onCreate()方法，或在Application的无参构造方法内，调用Application.registerActivityLifecycleCallbacks()方法 ，并实现ActivityLifecycleCallbacks接口。

public class BaseApplication extends Application {     public void onCreate() {         super.onCreate();         this.registerActivityLifecycleCallbacks(new ActivityLifecycleCallbacks() {  @Override  public void onActivityStopped(Activity activity) {      Log.e("====", activity+"onActivityStopped");  }  @Override  public void onActivityStarted(Activity activity) {      Log.e("====", activity+"onActivityStarted");  }  @Override  public void onActivitySaveInstanceState(Activity activity, Bundle outState) {      Log.e("====", activity + "onActivitySaveInstanceState");  }  @Override  public void onActivityResumed(Activity activity) {      Log.e("====", activity + "onActivityResumed");  }  @Override  public void onActivityPaused(Activity activity) {      Log.e("====", activity + "onActivityPaused");  }  @Override  public void onActivityDestroyed(Activity activity) {      Log.e("====", activity + "onActivityDestroyed");  }  @Override  public void onActivityCreated(Activity activity, Bundle savedInstanceState) {      Log.e("====", activity + "onActivityCreated");  }         });     }; } 

为了测试，再新建两个activity：MainActivity和SecondActivity，点击MainActivity里面的按钮可以跳转到SecondActivity。 MainActivity代码如下：

public class MainActivity extends ActionBarActivity {  private Button btn = null;  @Override  protected void onCreate(Bundle savedInstanceState) {   super.onCreate(savedInstanceState);   setContentView(R.layout.activity_main);   btn = (Button) findViewById(R.id.btn);   btn.setOnClickListener(new View.OnClickListener() {    @Override    public void onClick(View v) {     Intent i = new Intent(MainActivity.this,SecondActivity.class);     startActivity(i);    }   });   Log.e("====", "MainActivity  onCreate");  }  @Override  protected void onResume() {   super.onResume();   Log.e("====", "MainActivity  onResume");  }  @Override  protected void onPause() {   super.onPause();   Log.e("====", "MainActivity  onPause");  }  @Override  protected void onStart() {   super.onStart();   Log.e("====", "MainActivity  onStart");  } } 

SecondActivity代码类似，不再贴出来。运行app，输出如下

11-25 16:45:24.043 2829-2829/com.mxn.soul.demo E/====: com.mxn.soul.demo.MainActivity@2300e06conActivityCreated     11-25 16:45:24.179 2829-2829/com.mxn.soul.demo E/====: MainActivity  onCreate     11-25 16:45:24.238 2829-2829/com.mxn.soul.demo E/====: com.mxn.soul.demo.MainActivity@2300e06conActivityStarted     11-25 16:45:24.240 2829-2829/com.mxn.soul.demo E/====: MainActivity  onStart     11-25 16:45:24.242 2829-2829/com.mxn.soul.demo E/====: com.mxn.soul.demo.MainActivity@2300e06conActivityResumed     11-25 16:45:24.242 2829-2829/com.mxn.soul.demo E/====: MainActivity  onResume     11-25 16:45:36.768 2829-2829/com.mxn.soul.demo E/====: com.mxn.soul.demo.MainActivity@2300e06conActivityPaused     11-25 16:45:36.768 2829-2829/com.mxn.soul.demo E/====: MainActivity  onPause     11-25 16:45:36.820 2829-2829/com.mxn.soul.demo E/====: com.mxn.soul.demo.SecondActivity@13adc62aonActivityCreated     11-25 16:45:36.856 2829-2829/com.mxn.soul.demo E/====: SecondActivity  onCreate     11-25 16:45:36.858 2829-2829/com.mxn.soul.demo E/====: com.mxn.soul.demo.SecondActivity@13adc62aonActivityStarted     11-25 16:45:36.858 2829-2829/com.mxn.soul.demo E/====: SecondActivity onStart     11-25 16:45:36.859 2829-2829/com.mxn.soul.demo E/====: com.mxn.soul.demo.SecondActivity@13adc62aonActivityResumed     11-25 16:45:36.859 2829-2829/com.mxn.soul.demo E/====: SecondActivity onResume     11-25 16:45:37.321 2829-2829/com.mxn.soul.demo E/====: com.mxn.soul.demo.MainActivity@2300e06conActivitySaveInstanceState     11-25 16:45:37.321 2829-2829/com.mxn.soul.demo E/====: com.mxn.soul.demo.MainActivity@2300e06conActivityStopped

可以看到ActivityLifecycleCallbacks的回调在activity生命周期方法之前，这是因为我的log信息写在super之后：

@Override     protected void onResume() {         super.onResume();          Log.e("====", "MainActivity  onResume");     }

如果把log写在super之前，那么结果就是相反的了。

@Override     protected void onResume() {         Log.e("====", "MainActivity  onResume");         super.onResume();     }

输出如下：

11-25 17:28:15.652 27469-27469/? E/====: MainActivity  onResume     11-25 17:28:15.653 27469-27469/? E/====: com.mxn.soul.demo.MainActivity@2300e06conActivityResumed

用ActivityLifecycleCallbacks管理Activity堆栈

可以用ActivityLifecycleCallbacks和LinkedList来管理所有的Activity，可以实现完全退出一个应用。

public class BaseApplication extends Application  implements Application.ActivityLifecycleCallbacks {  private LinkedList<ActivityInfo> mExistedActivitys = new LinkedList<>();  private static BaseApplication mInstance;  public static  synchronized BaseApplication getInstance() {   return mInstance;  }  public void onCreate() {   super.onCreate();   registerActivityLifecycleCallbacks(this);    mInstance = this;  }  @Override  public void onActivityCreated(Activity activity, Bundle savedInstanceState) {   if (null != mExistedActivitys && null != activity) {    // 把新的 activity 添加到最前面，和系统的 activity 堆栈保持一致    mExistedActivitys.offerFirst(new ActivityInfo(activity,ActivityInfo.STATE_CREATE));   }  }  @Override  public void onActivityStarted(Activity activity) {  }  @Override  public void onActivityResumed(Activity activity) {  }  @Override  public void onActivityPaused(Activity activity) {  }  @Override  public void onActivityStopped(Activity activity) {  }  @Override  public void onActivitySaveInstanceState(Activity activity, Bundle outState) {  }  @Override  public void onActivityDestroyed(Activity activity) {   if (null != mExistedActivitys && null != activity) {    ActivityInfo info = findActivityInfo(activity);    if (null != info) {     mExistedActivitys.remove(info);    }   }  }  class ActivityInfo {   private final static int STATE_NONE = 0;   private final static int STATE_CREATE = 1;   Activity mActivity;   int mState;   ActivityInfo() {    mActivity = null;    mState = STATE_NONE;   }   ActivityInfo(Activity activity, int state) {    mActivity = activity;    mState = state;   }  }  public void exitAllActivity() {   if (null != mExistedActivitys) {    // 先暂停监听（省得同时在2个地方操作列表）    unregisterActivityLifecycleCallbacks( this );    // 弹出的时候从头开始弹，和系统的 activity 堆栈保持一致    for (ActivityInfo info : mExistedActivitys) {     if (null == info || null == info.mActivity) {      continue;     }     try {      info.mActivity.finish();     } catch (Exception e) {      e.printStackTrace();     }    }    mExistedActivitys.clear();    // 退出完之后再添加监听    registerActivityLifecycleCallbacks( this );   }  }  private ActivityInfo findActivityInfo(Activity activity) {   if (null == activity || null == mExistedActivitys) {    return null;   }   for (ActivityInfo info : mExistedActivitys) {    if (null == info) {     continue;    }    if (activity.equals(info.mActivity)) {     return info;    }   }   return null;  } } 

结束程序时调用：

BaseApplication.getInstance().exitAllActivity() ;

但是如果应用内有多个进程，每创建一个进程就会跑一次Application的onCreate方法，每个进程内存都是独立的， 所以通过这种方式无法实现将应用的Activity放在同一个LinkedList中，不能实现完全退出一个应用。