android 4.4.X:taskAffinity&launchmode vs. Activity生命周期

我开发了一个简单的应用程序,它解释了我注意到的Android 4.4.X设备上的一些奇怪的行为.

假设我想要进行2次"主要"活动,其中第一次活动表示"Hello"(通过启动"HelloActivity")每秒恢复一次,第二次android:launchMode="singleTask" android:taskAffinity=".MyAffinity"定义.第二个是由第一个开始的.

我的守则

清单非常简单:

MainActivity在按钮单击时启动AffinityTestActivity并记录其生命周期.它还会在每次恢复时启动HelloActivity:

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        System.out.println(this+" onCreate");
        super.onCreate(savedInstanceState);

        Button b = new Button(MainActivity.this);
        b.setText("START AFFINITY TEST ACTIVITY");
        b.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                System.out.println(this+" starts "+AffinityTestActivity.class.getSimpleName());
                Intent intent = new Intent(MainActivity.this, AffinityTestActivity.class);
                startActivity(intent);
            }
        });
        setContentView(b);
    }

    private boolean skipHello = true;

    @Override
    protected void onResume() {
        System.out.println(this+" onResume");
        super.onResume();

        if (!skipHello) {
            System.out.println(this+" starts "+HelloActivity.class.getSimpleName());
            Intent intent = new Intent(MainActivity.this, HelloActivity.class);
            startActivity(intent);
            skipHello = true;
        } else {
            skipHello = false;
        }
    }

    @Override
    protected void onPause() {
        System.out.println(this+" onPause");
        super.onPause();
    }

    @Override
    protected void onDestroy() {
        System.out.println(this+" onDestroy");
        super.onDestroy();
    }

}

AffinityTestActivity在按钮单击时调用finish()并记录其生命周期:

public class AffinityTestActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        System.out.println(this+" onCreate");
        super.onCreate(savedInstanceState);

        Button b = new Button(AffinityTestActivity.this);
        b.setText("FINISH");
        b.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                System.out.println(this+" finishes");
                finish();
            }
        });
        setContentView(b);
    }

    @Override
    protected void onResume() {
        System.out.println(this+" onResume");
        super.onResume();
    }

    @Override
    protected void onPause() {
        System.out.println(this+" onPause");
        super.onPause();
    }

    @Override
    protected void onDestroy() {
        System.out.println(this+" onDestroy");
        super.onDestroy();
    }
}

HelloActivity实际上与AffinityTestActivity相同 - 它只有按钮来调用finish()和printlns来记录它的生命周期.

测试场景

启动MainActivity.

启动AffinityTestActivity.

完成AffinityTestActivity(当AffinityTestActivity完成时,恢复MainActivity并启动HelloActivity).

分析输出.

日志

Android 4.4.2和4.4.3 :(在Nexus 7 II和三星Galaxy S5上测试)正如您所看到的,日志以HelloActivity的onPause结束,这没有意义(HelloActivity在步骤3中显示在顶部).此外,AffinityTestActivity不会被破坏,MainActivity也不会被暂停.

06-20 11:13:20.547: I/System.out(18650): com.example.affinitylaunchmodebugtest.MainActivity@41f17e50 onCreate
06-20 11:13:20.557: I/System.out(18650): com.example.affinitylaunchmodebugtest.MainActivity@41f17e50 onResume
06-20 11:13:25.371: I/System.out(18650): com.example.affinitylaunchmodebugtest.MainActivity$1@41f6e5c0 starts AffinityTestActivity
06-20 11:13:25.581: I/System.out(18650): com.example.affinitylaunchmodebugtest.MainActivity@41f17e50 onPause
06-20 11:13:25.591: I/System.out(18650): com.example.affinitylaunchmodebugtest.AffinityTestActivity@41f6a480 onCreate
06-20 11:13:25.611: I/System.out(18650): com.example.affinitylaunchmodebugtest.AffinityTestActivity@41f6a480 onResume
06-20 11:13:36.452: I/System.out(18650): com.example.affinitylaunchmodebugtest.AffinityTestActivity$1@41f1ede8 finishes
06-20 11:13:36.662: I/System.out(18650): com.example.affinitylaunchmodebugtest.AffinityTestActivity@41f6a480 onPause
06-20 11:13:36.682: I/System.out(18650): com.example.affinitylaunchmodebugtest.MainActivity@41f17e50 onResume
06-20 11:13:36.682: I/System.out(18650): com.example.affinitylaunchmodebugtest.MainActivity@41f17e50 starts HelloActivity
06-20 11:13:36.782: I/System.out(18650): com.example.affinitylaunchmodebugtest.HelloActivity@41f8dbb8 onCreate
06-20 11:13:36.802: I/System.out(18650): com.example.affinitylaunchmodebugtest.HelloActivity@41f8dbb8 onResume
06-20 11:13:36.852: I/System.out(18650): com.example.affinitylaunchmodebugtest.HelloActivity@41f8dbb8 onPause

较旧的Android版本(<4.4.2,在2.3.5.,4.1.2和4.2.1设备上测试,4.0.3模拟器)按预期工作 - 在onResume和AffinityTestActivity被销毁后,HelloActivity不会暂停:

06-20 11:16:30.867: I/System.out(3296): com.example.affinitylaunchmodebugtest.MainActivity@40f998b0 onCreate
06-20 11:16:30.907: I/System.out(3296): com.example.affinitylaunchmodebugtest.MainActivity@40f998b0 onResume
06-20 11:16:34.157: I/System.out(3296): com.example.affinitylaunchmodebugtest.MainActivity$1@40f9b350 starts AffinityTestActivity
06-20 11:16:34.277: I/System.out(3296): com.example.affinitylaunchmodebugtest.MainActivity@40f998b0 onPause
06-20 11:16:34.297: I/System.out(3296): com.example.affinitylaunchmodebugtest.AffinityTestActivity@40fab810 onCreate
06-20 11:16:34.357: I/System.out(3296): com.example.affinitylaunchmodebugtest.AffinityTestActivity@40fab810 onResume
06-20 11:16:38.687: I/System.out(3296): com.example.affinitylaunchmodebugtest.AffinityTestActivity$1@40fad640 finishes
06-20 11:16:38.707: I/System.out(3296): com.example.affinitylaunchmodebugtest.AffinityTestActivity@40fab810 onPause
06-20 11:16:38.717: I/System.out(3296): com.example.affinitylaunchmodebugtest.MainActivity@40f998b0 onResume
06-20 11:16:38.717: I/System.out(3296): com.example.affinitylaunchmodebugtest.MainActivity@40f998b0 starts HelloActivity
06-20 11:16:38.747: I/System.out(3296): com.example.affinitylaunchmodebugtest.MainActivity@40f998b0 onPause
06-20 11:16:38.777: I/System.out(3296): com.example.affinitylaunchmodebugtest.HelloActivity@40fbdd48 onCreate
06-20 11:16:38.827: I/System.out(3296): com.example.affinitylaunchmodebugtest.HelloActivity@40fbdd48 onResume
06-20 11:16:39.877: I/System.out(3296): com.example.affinitylaunchmodebugtest.AffinityTestActivity@40fab810 onDestroy

我的问题

为什么我的HelloActivity在Android 4.4.X设备上启动并在顶部显示后暂停？

我如何避免它并强制应用程序具有"正常"活动生命周期,因为较旧的Android版本(<4.4.2)会这样做？

我开发的应用程序要复杂得多,并且与其活动的生命周期一起工作,这种行为违反了我的应用程序的功能.

非常感谢你!