public class BaseActivity extends AppCompatActivity {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
 ActivityContainer.getInstance().addActivity(this);
   }

 

  @Override
  protected void onDestroy() {
    super.onDestroy();
    ActivityContainer.getInstance().removeActivity(this);
  }
}

class ActivityContainer {
  private ActivityContainer(){

  }

  private static ActivityContainer instance = new ActivityContainer();
  private static List<AppCompatActivity> activityStack = new LinkedList<>();


  public static ActivityContainer getInstance(){
    return instance;
  }

  public void addActivity(AppCompatActivity aty) {
    activityStack.add(aty);
  }

  public void removeActivity(AppCompatActivity aty) {
    activityStack.remove(aty);
  }


  /**
   * 结束所有的Activity
   */
  public void finishAllActivity(){
    for (int i = 0 , size = activityStack.size(); i < size;i++) {
      if (null != activityStack.get(i)) {
        activityStack.get(i).finish();
      }
    }
    activityStack.clear();
  }
}

ActivityContainer.getInstance().finishAllActivity();

public class BaseActivity extends AppCompatActivity {

  protected static final String EXITACTION = "action.exit";

  private ExitReceiver mExitReceiver = new ExitReceiver();

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    IntentFilter intentFilter = new IntentFilter();
    intentFilter.addAction(EXITACTION);
    registerReceiver(mExitReceiver, intentFilter);
  }

 

  @Override
  protected void onDestroy() {
    super.onDestroy();
    unregisterReceiver(mExitReceiver);
  }

  class ExitReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
      BaseActivity.this.finish();
    }
  }

}

@Override
  protected void onNewIntent(Intent intent) {
    super.onNewIntent(intent);
    Log.e("main", "onNewIntent调用");
    if (intent != null) {
      boolean isExit = intent.getBooleanExtra(ACTION, false);
      if (isExit) {
        this.finish();
      }
    }
  }

 @Override
  public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
      if (isExit) {
        this.finish();
      }else {
        Toast.makeText(this, "再按一次退出", Toast.LENGTH_SHORT).show();
        isExit = true;
        new Handler().postDelayed(new Runnable() {
          @Override
          public void run() {
            isExit = false;
          }
        },2000);
        return true;
      }
    }
    return super.onKeyDown(keyCode, event);
  }

new Timer().schedule(new TimerTask() {
          @Override
          public void run() {
           isExit = false;
          }
        },2000);