android - 如何在 fragment 构造函数中获取父 Activity 引用？

Question

我有一个 GameActivity Activity 其中一个方法是:

/** Show "Game is finished" dialog. */
public void showFinishedDlg(int bodyMsgRes) {
    GameFinishedDlgFragment.newInstance(bodyMsgRes).show(
            this.getFragmentManager(), "finished_dlg");
}

这是方法创建的对话框 fragment :

public class GameFinishedDlgFragment extends DialogFragment {

    static GameFinishedDlgFragment newInstance(int bodyMsgRes) {

        GameFinishedDlgFragment frag = new GameFinishedDlgFragment();
        Bundle bundle = new Bundle();
        bundle.putInt("body_msg", bodyMsgRes);
        frag.setArguments(bundle);
        return frag;
    }

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        Bundle args = getArguments();
        int bodyMsgRes = args.getInt("body_msg");

        // Use the Builder class for convenient dialog construction
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setMessage(bodyMsgRes)
                .setPositiveButton(R.string.new_game, new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        // PROBLEM HERE. TODO: Restart GameActivity
                        this.parentActivity.recreate();
                    }
                });

        // Create the AlertDialog object and return it
        return builder.create();
    }
}

我试图让对话框按钮的 onClick 重新启动 GameActivity，但我不知道如何获取对该 Activity 实例的引用。

如果我尝试:

this.parentActivity.recreate();

编译器告诉我:

Cannot resolve symbol 'parentActivity'

Answer 1

请覆盖 fragment 的 onAttach 方法。传入的 Activity 参数是您的父 Activity 。

fragment 的生命周期方法: http://developer.xamarin.com/guides/android/platform_features/fragments/part_1_-_creating_a_fragment/Images/fragment_lifecycle.png

官方引用: http://developer.android.com/reference/android/app/DialogFragment.html#onAttach(android.app.Activity)

或者在 onAttach 完成后，在你编写代码的任何地方调用 getActivity() !调用它，在 onAttach 之前它给出 NULL

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