Android-关闭对话框片段后出现小对话框

我已经制作了这个简单的对话框片段，以显示在主屏幕上，除了在关闭片段对话框时，第二个小对话框中出现了Dialogue一词，可以正常工作。我无法终生知道它的来源。

有人有什么建议吗？可能与一连串的类被调用有关，并且其中一类正在再次启动警报但没有自定义布局视图吗？

对话框片段。

public class DialogFragmentTest extends DialogFragment implements View.OnClickListener{

private AlertDialog.Builder mBuilder;
private AlertDialog mAlertDialog;
private View mDialogView;
private Button mOkBtn, mCancelBtn;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    mDialogView = inflater.inflate(R.layout.dialog_layout, container, false);

    Log.d("DialogFrag", "onCreate");

   // mBuilder = new AlertDialog.Builder(getContext());

    mOkBtn = (Button) mDialogView.findViewById(R.id.ok);
    mCancelBtn = (Button) mDialogView.findViewById(R.id.cancel);

    mOkBtn.setOnClickListener(this);
    mCancelBtn.setOnClickListener(this);

    return mDialogView;
}


@Override
public void onClick(View view) {
    switch (view.getId()) {
        case R.id.ok:

            this.dismiss();

            break;
        case R.id.cancel:
            this.dismiss();
            break;
    }
}

}

对话框接收器类。

public class AlertDialogReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
    Intent alarmIntent = new Intent("android.intent.action.MAIN");
    alarmIntent.setClass(context, AlarmDialogClass.class);
    alarmIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    context.startActivity(alarmIntent);
}
}

实例化片段的类。

public class AlarmDialogClass extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Log.d("AlarmClass", "onCreate:");

    FragmentManager fm = getFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    DialogFragmentTest dft = new DialogFragmentTest();
    dft.show(fm, "Sample Fragment");


}

}

manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest package="com.android.shnellers.dialogue"
      xmlns:android="http://schemas.android.com/apk/res/android">

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN"/>

            <category android:name="android.intent.category.LAUNCHER"/>
        </intent-filter>
    </activity>
    <activity
        android:name=".AlarmDialogClass"
        android:theme="@android:style/Theme.Dialog"
        android:launchMode="singleInstance" />

    <receiver android:process=":remote" android:name=".AlertDialogReceiver"/>
</application>