Question

编辑*在Android设备上测试时发生此问题。在对emultor进行测试时，不会出现此问题。

我正在开始一个新的活动，我看到在调用onResume后立即调用onPause。如果我查看日志，它会在onResume之后进入Idle。因此，在调用onResume之后立即导致onPause。

来电者活动 - 通过意图调用onClick上的MainActivity。

public class TestActivity extends AppCompatActivity implements View.OnClickListener{

    String TAG = "acr";
    Button testBtn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test);
        testBtn = (Button) findViewById(R.id.testBtn);
        testBtn.setOnClickListener(this);
    }

    @Override
    protected void onPause() {
        super.onPause();
        Log.i(TAG, "on pause called on TestActivity ");
    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.i(TAG, "on resume called on  TestActivity ");
    }

    @Override
    public void onClick(View v) {
        switch(v.getId()){
            case R.id.testBtn:
                Intent mainIntent = new Intent(this, MainActivity.class);
                TestActivity.this.startActivity(mainIntent);
                break;
        }
    }
}

有错误的活动

public class MainActivity extends AppCompatActivity{

    public static final String TAG = "acrx";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }


    @Override
    protected void onPause() {
        super.onPause();
        Log.i(TAG, "on pause called on mainactivity");
    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.i(TAG, "on resume Called on Main activity");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.i(TAG, "on stop Called on Main activity");
    }
}

日志

12-06 23:24:19.751 22983-22983/com.example.m1alesis.smartcardreader I/acrx: on resume Called on Main activity
12-06 23:24:19.751 22983-22983/com.example.m1alesis.smartcardreader D/SecWifiDisplayUtil: Metadata value : SecSettings2
12-06 23:24:19.751 22983-22983/com.example.m1alesis.smartcardreader D/ViewRootImpl: #1 mView = com.android.internal.policy.PhoneWindow$DecorView{5ce8491 I.E...... R.....ID 0,0-0,0}
12-06 23:24:19.781 22983-23012/com.example.m1alesis.smartcardreader D/mali_winsys: EGLint new_window_surface(egl_winsys_display*, void*, EGLSurface, EGLConfig, egl_winsys_surface**, egl_color_buffer_format*, EGLBoolean) returns 0x3000,  [1440x2560]-format:1
12-06 23:24:19.811 22983-22983/com.example.m1alesis.smartcardreader W/DisplayListCanvas: DisplayListCanvas is started on unbinded RenderNode (without mOwningView)
12-06 23:24:19.831 22983-22983/com.example.m1alesis.smartcardreader D/ViewRootImpl: MSG_RESIZED_REPORT: ci=Rect(0, 96 - 0, 0) vi=Rect(0, 96 - 0, 0) or=1
12-06 23:24:19.871 22983-23012/com.example.m1alesis.smartcardreader D/OpenGLRenderer: endAllActiveAnimators on 0x7f9c17ec00 (RippleDrawable) with handle 0x7f9ccc8b60
12-06 23:24:19.871 22983-22983/com.example.m1alesis.smartcardreader I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@fa2f707 time:376798424
12-06 23:24:20.131 22983-22983/com.example.m1alesis.smartcardreader V/ActivityThread: updateVisibility : ActivityRecord{e78cff6 token=android.os.BinderProxy@a67fd36 {com.example.m1alesis.smartcardreader/com.example.m1alesis.smartcardreader.TestActivity}} show : false
12-06 23:24:31.561 22983-22983/com.example.m1alesis.smartcardreader I/acrx: on pause called on mainactivity
12-06 23:24:31.701 22983-22983/com.example.m1alesis.smartcardreader I/acrx: on resume Called on Main activity
12-06 23:24:31.721 22983-22983/com.example.m1alesis.smartcardreader I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@fa2f707 time:376810271

Answer 1

我在我的测试活动中尝试过，但我没有遇到你的问题。我的MainActivity和TestActivity上只有一个按钮。

我在这里找到了一些东西：Pausing and Resuming an Activity。

这是有趣的部分：

注意：当系统调用您的活动的onPause（）方法时，系统可能会发出活动暂停的信号，并且用户可能会将焦点返回到您的活动，或者该应用程序在多窗口中运行模式。但是，此方法调用也可能是用户离开您的活动的第一个指示。

Answer 2

我遇到了同样的问题，对我而言，它与启动的活动和屏幕没有打开有关 - 我只是在屏幕关闭后才看到它（例如，在触摸电源按钮然后回家再次恢复之后）

这是其他人也看到的行为 - 我发现这个问题和答案都有用的参考：OnPause and OnStop() called immediately after starting activity

帮助我了解行为的关键词是：

请记住，onResume不是您的活动对用户可见的最佳指标;诸如键盘锁之类的系统窗口可以在前面。使用onWindowFocusChanged（boolean）来确定您的活动对用户可见

Answer 3

就我而言，同样的问题是由 ActivityCompat.requestPermissions(this, new String[]{Manifest.permission...); 引起的。

 * This method may start an activity allowing the user to choose which permissions
 * to grant and which to reject. Hence, you should be prepared that your activity
 * may be paused and resumed. Further, granting some permissions may require
 * a restart of you application. In such a case, the system will recreate the
 * activity stack before delivering the result to your
 * {@link OnRequestPermissionsResultCallback#onRequestPermissionsResult(int, String[], int[])}.

这明显减慢了应用的启动速度。

在OnResume

3 个答案: