按下主页按钮后关闭对话框片段时，onSavedInstanceState 后无法执行此任务

Question

我有一个处理用户注册的活动 (FragmentActivity)。当任务在活动中异步处理时，单击按钮会显示 DialogFragment。然后在处理完任务后，将关闭 FragmentDialog。一切运行顺利，即使配置更改（如改变方向），但我发现如果我在后台任务运行时按下主页按钮，应用程序在它试图关闭 FragmentDialog 并且当我重新启动应用程序时崩溃，我发现对话框仍在运行。

我搜索并找到了很多讨论、解决方案和解决方法，here、here 和 here。但我无法实施其中任何一个来解决我的问题。

这是我的工作：

为注册用户点击按钮调用的方法：

    private void startRegDialog(final String phoneNumber, String password) {
    Log.i("tag", "startregdailog called");

    verifiedUser = false;

            //start Dialog fragment here.
    final SignUpDialogFragment mDialogFragment = SignUpDialogFragment.newInstance();
    mDialogFragment.show(getSupportFragmentManager(), "dailogFragment");

    ParseUser CreateNewUser = new ParseUser();

    CreateNewUser.setUsername(phoneNumber);
    CreateNewUser.setPassword(password);
    CreateNewUser.put("userVerified", verifiedUser);
    Log.i("tag", "starting task");

    CreateNewUser.signUpInBackground(new SignUpCallback() {

        @Override
        public void done(ParseException e) {
            Log.i("tag", "task done");

               //Dismiss Dialog after receiving result

            if(mDialogFragment !=null){
            mDialogFragment.dismiss();
            }

            if(e != null){
                Log.i("Tag", "user not Created");
                String errorMessage = e.getMessage().toString();
                onError(errorMessage);

            } 
            else {
                Log.i("Tag", "userSuccessfully Created");
                Intent VerifyAccount = new Intent(context, VerifyAccount.class);
                VerifyAccount.putExtra("phoneNo", phoneNumber);
                startActivity(VerifyAccount);
            }
        }
    });
}

这里是 LOGCAT 输出

  03-17 22:12:40.070: E/AndroidRuntime(16000): FATAL EXCEPTION: main
  03-17 22:12:40.070: E/AndroidRuntime(16000): java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1343)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1361)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:595)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at android.support.v4.app.BackStackRecord.commit(BackStackRecord.java:574)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at android.support.v4.app.DialogFragment.dismissInternal(DialogFragment.java:189)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at android.support.v4.app.DialogFragment.dismiss(DialogFragment.java:155)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at com.example.razcat.CreateAccount$3.done(CreateAccount.java:273)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at com.parse.SignUpCallback.internalDone(SignUpCallback.java:39)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at com.parse.SignUpCallback.internalDone(SignUpCallback.java:1)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at com.parse.Parse$6$1.run(Parse.java:834)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at android.os.Handler.handleCallback(Handler.java:615)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at android.os.Handler.dispatchMessage(Handler.java:92)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at android.os.Looper.loop(Looper.java:155)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at android.app.ActivityThread.main(ActivityThread.java:5454)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at java.lang.reflect.Method.invokeNative(Native Method)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at java.lang.reflect.Method.invoke(Method.java:511)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1029)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:796)
  03-17 22:12:40.070: E/AndroidRuntime(16000):  at dalvik.system.NativeStart.main(Native Method)

 Please any help would be useful thanks. 

Answer 1

要删除 Dialog Fragment，您需要通过它的标签调用它，然后只有您可以关闭它。在您的情况下，您已将“dailogFragment”作为标签。

mDialogFragment.show(getSupportFragmentManager(), "dailogFragment");

所以现在要删除它，首先通过它的标签调用它，如下所示：

Fragment mDialogFragment= getSupportFragmentManager().findFragmentByTag("dailogFragment");
//then check if it's null
    if (mDialogFragment!= null) {
        DialogFragment df = (DialogFragment) mDialogFragment;
//Now dismiss.
        df.dismiss();
    }