Activity 泄露了窗口/对话框（又是这个！）

Question

是的，我已经阅读了无数关于非常相似问题的问题。

我的代码很简单：我只是在onCreate 上使用showDialog(int id)，然后旋转设备。 代码就是那个（测试用例），这足以导致问题。我的理解是showDialog 的方法会解决这个问题......对话框会消失，然后在更改后稍后会调用onCreate 并再次干净地显示对话框。但不是。 这个推理有什么问题？

我（想我）理解the cause，但我不知道如何解决。甚至 iosched 应用程序在执行 EULA 窗口时也存在同样的问题（更改 eula 对话框上的方向，您就会得到泄漏）。我已经阅读了关于在 onPause 上关闭对话框的信息，但是 1）我可能会在尚未显示时关闭对话框，并且 2）跟踪对话框似乎工作量太大。必须有更稳健的方法。

那么...处理该问题所需的更简洁的代码是什么？

谢谢。

---

日志错误输出：

01-30 00:27:18.615: E/WindowManager(20316): Activity com.test.PreSetupActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@418e0c28 that was originally added here
01-30 00:27:18.615: E/WindowManager(20316): android.view.WindowLeaked: Activity com.test.PreSetupActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@418e0c28 that was originally added here
01-30 00:27:18.615: E/WindowManager(20316):     at android.view.ViewRootImpl.<init>(ViewRootImpl.java:343)
01-30 00:27:18.615: E/WindowManager(20316):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:245)
01-30 00:27:18.615: E/WindowManager(20316):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:193)
01-30 00:27:18.615: E/WindowManager(20316):     at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:118)
01-30 00:27:18.615: E/WindowManager(20316):     at android.view.Window$LocalWindowManager.addView(Window.java:537)
01-30 00:27:18.615: E/WindowManager(20316):     at android.app.Dialog.show(Dialog.java:274)
01-30 00:27:18.615: E/WindowManager(20316):     at com.test.PreSetupActivity.onCreate(PreSetupActivity.java:88)
01-30 00:27:18.615: E/WindowManager(20316):     at android.app.Activity.performCreate(Activity.java:4465)
01-30 00:27:18.615: E/WindowManager(20316):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
01-30 00:27:18.615: E/WindowManager(20316):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1919)
01-30 00:27:18.615: E/WindowManager(20316):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
01-30 00:27:18.615: E/WindowManager(20316):     at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3347)
01-30 00:27:18.615: E/WindowManager(20316):     at android.app.ActivityThread.access$700(ActivityThread.java:122)
01-30 00:27:18.615: E/WindowManager(20316):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1150)
01-30 00:27:18.615: E/WindowManager(20316):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-30 00:27:18.615: E/WindowManager(20316):     at android.os.Looper.loop(Looper.java:137)
01-30 00:27:18.615: E/WindowManager(20316):     at android.app.ActivityThread.main(ActivityThread.java:4340)
01-30 00:27:18.615: E/WindowManager(20316):     at java.lang.reflect.Method.invokeNative(Native Method)
01-30 00:27:18.615: E/WindowManager(20316):     at java.lang.reflect.Method.invoke(Method.java:511)
01-30 00:27:18.615: E/WindowManager(20316):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
01-30 00:27:18.615: E/WindowManager(20316):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
01-30 00:27:18.615: E/WindowManager(20316):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

有一个内部类作为你的状态持有者，并有一个布尔字段指示你的对话框是否正在显示。使用onRetainNonConfigurationInstance 跟踪整个方向变化，并在onResume 上重新显示对话框

这是一些代码+伪代码：

public class ProfileActivity extends Activity {
  private StateHolder mStateHolder;
  private Dialog dialog;

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Object retained = getLastNonConfigurationInstance();
    if (retained != null && retained instanceof StateHolder) {
      mStateHolder = (StateHolder) retained;
    } else {
      mStateHolder = new StateHolder();
    }
  }

  @Override
  public Object onRetainNonConfigurationInstance() {
    return mStateHolder;
  }

  @Override
  public void onPause() {
    super.onPause();
    if(dialog != null && dialog.isShowing()) {
      dialog.dismiss();
    }
  }

  @Override
  public void onResume() {
    if(mStateHolder.mIsShowingDialog) {
      dialog.show();
    }
  }

  private void showDialog() {
    mStateHolder.mIsShowingDialog = true;
    dialog.show();
  }

  private static class StateHolder {
    boolean mIsShowingDialog;
    public StateHolder() {}
  }

}