Android Childactivity getParent问题？

Question

基本上我在我的应用程序中使用 ActivityGroup。我有这种情况：

我有带有活动 A 的 Tabhost。

Activity A 创建 childActivity B。

A  --->  B

startChildActivity("CollectionList", new Intent(this,MyCollectionList.class));

活动 B 创建 3 个子活动 C、D。

B  ---> C (childActivity of B)
startChildActivity("Recommended", new Intent(MyCollectionList.this,Recommended.class));


B  ---> D (childActivity of B)
startChildActivity("ExpectSoon", new Intent(MyCollectionList.this,ExpectSoon.class));

B 也创建了另一个 childActivity，将其命名为 E。

B  ---> E
Intent previewMessage = new Intent(getParent(), MyCollectionId.class);
TabGroupActivity parentActivity = (TabGroupActivity)getParent();
parentActivity.startChildActivity("MyCollectionId", previewMessage);

所以基本上活动 C 和 D 也可以启动活动 E，使用：

            Intent previewMessage = new Intent(getParent(), MyCollectionId.class);
            TabGroupActivity parentActivity = (TabGroupActivity)getParent();
            parentActivity.startChildActivity("MyCollectionId", previewMessage);

我已经重写了 onBackPressed 方法，所以我可以控制后退按钮。它看起来像这样：

    private ArrayList<String> mIdList;

@Override
  public void  onBackPressed  () {
      int length = mIdList.size();
      if ( length >=1) {
          Activity current = getLocalActivityManager().getActivity(mIdList.get(length-1));
          current.finish();
      }
  }

所以我的问题是，当我在活动 E 中并按下后退按钮时，我的应用程序关闭。我遇到的另一个问题是活动 E 中的警报对话框。

Button deactivate = (Button) findViewById(R.id.deactivate);
        deactivate.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                new AlertDialog.Builder( getParent() )
                .setTitle( "Warning" )
                .setMessage( "The collection will be removed completely from the device.You can reactivate it later again.This operation requires internet connection." )
                .setPositiveButton( "Go ahead", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        Log.d("AlertDialog", "Positive");
                    }
                })
                .setNegativeButton( "Cancel", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        Log.d("AlertDialog","Negative");
                    }
                })
                .show();    

            }

    });

当我从 A 启动活动 E 时，当我单击按钮时，将显示警报对话框，一切正常。但是当我从 C 或 D 启动活动 E 时，它会抛出异常：

08-15 15:48:22.819: ERROR/AndroidRuntime(32440): FATAL EXCEPTION: main
08-15 15:48:22.819: ERROR/AndroidRuntime(32440): android.view.WindowManager$BadTokenException: Unable to add window -- token android.app.LocalActivityManager$LocalActivityRecord@4630ea20 is not valid; is your activity running?
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at android.view.ViewRoot.setView(ViewRoot.java:509)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at android.view.Window$LocalWindowManager.addView(Window.java:424)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at android.app.Dialog.show(Dialog.java:241)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at android.app.AlertDialog$Builder.show(AlertDialog.java:802)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at com.stampii.stampii.mystampii.MyCollectionId$4.onClick(MyCollectionId.java:75)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at android.view.View.performClick(View.java:2408)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at android.view.View$PerformClick.run(View.java:8817)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at android.os.Handler.handleCallback(Handler.java:587)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at android.os.Handler.dispatchMessage(Handler.java:92)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at android.os.Looper.loop(Looper.java:144)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at android.app.ActivityThread.main(ActivityThread.java:4937)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at java.lang.reflect.Method.invokeNative(Native Method)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at java.lang.reflect.Method.invoke(Method.java:521)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-15 15:48:22.819: ERROR/AndroidRuntime(32440):     at dalvik.system.NativeStart.main(Native Method)

编辑：

我的 startChildActivity 看起来像这样：

public void startChildActivity(String Id, Intent intent) {     
      Window window = getLocalActivityManager().startActivity(Id,intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP));
      if (window != null) {
          mIdList.add(Id);
          setContentView(window.getDecorView()); 
      } 

}

最新的LogCat，在ActivityE中使用Recommended.parentActivity时：

        new AlertDialog.Builder( Recommended.parentActivity )


08-15 16:33:53.509: ERROR/AndroidRuntime(1967): FATAL EXCEPTION: main
08-15 16:33:53.509: ERROR/AndroidRuntime(1967): java.lang.NullPointerException
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at com.android.internal.app.AlertController$AlertParams.<init>(AlertController.java:743)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at android.app.AlertDialog$Builder.<init>(AlertDialog.java:273)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at com.stampii.stampii.mystampii.MyCollectionId$4.onClick(MyCollectionId.java:62)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at android.view.View.performClick(View.java:2408)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at android.view.View$PerformClick.run(View.java:8817)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at android.os.Handler.handleCallback(Handler.java:587)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at android.os.Handler.dispatchMessage(Handler.java:92)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at android.os.Looper.loop(Looper.java:144)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at android.app.ActivityThread.main(ActivityThread.java:4937)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at java.lang.reflect.Method.invokeNative(Native Method)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at java.lang.reflect.Method.invoke(Method.java:521)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-15 16:33:53.509: ERROR/AndroidRuntime(1967):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

你可以做一件事 在ActivityA.java中

public static Activity parentActivity;

onCreate()
{
     parentActivity=this;
} 
// start your child activity ie(E)

ActivityE.java

Button deactivate = (Button) findViewById(R.id.deactivate);
        deactivate.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                new AlertDialog.Builder( ActivityA.parentActivity.this )
                .setTitle( "Warning" )
                .setMessage( "The collection will be removed completely from the device.You can reactivate it later again.This operation requires internet connection." )
                .setPositiveButton( "Go ahead", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        Log.d("AlertDialog", "Positive");
                    }
                })
                .setNegativeButton( "Cancel", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        Log.d("AlertDialog","Negative");
                    }
                })
                .show();    

            }

    });