如何禁用第二个底部工作表对话框上的后退按钮？

Question

我正在创建一个 MainActivity。此活动有一个按钮可以打开 Fragment，而 Fragment 有一个按钮可以打开底部工作表对话框。

当我在 Fragment 上时，我可以按 Back 按钮返回 MainActivity。但是，当我已经打开底部对话框时，我想禁用后退按钮，以便用户在显示底部对话框时无法按后退按钮。那么我该怎么做呢？谢谢你。

主要活动

public class MainActivity extends SdwBaseActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}

public void startAction(View view){
    LoadCashTutorialScreen loadCashTutorialScreen = LoadCashTutorialScreen.newInstance();
 getSupportFragmentManager().beginTransaction().replace(R.id.container, loadCashTutorialScreen, "LoadCashTutorialScreen").addToBackStack("LoadCashTutorialScreen").commit();
}

@Override
public void onBackPressed(){
      super.onBackPressed()
      //do something so that the back button is disable when the Bottom Dialog is showing
}
}

分段：

public class LoadCashTutorialScreen extends Fragment{
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = initView(inflater, container, R.layout.load_cash_tutorial_screen);
        Button startDialog = view.findViewById(R.id.dialogButton);
        startDialog.setOnClickListener(view1 -> {
            MyBottomDialog dialog = new MyBottomDialog();
            dialog.show(activity.getSupportFragmentManager(), "BottomDialog");
        });

        return view;
    }
}

对话：

public class MyBottomDialog extends BottomSheetDialogFragment {
    @Override
    public void setupDialog(@NonNull Dialog dialog, int style) {
        super.setupDialog(dialog, style);
        View contentView = View.inflate(getContext(), R.layout.load_cash_bottom_dialog, null);
        dialog.setContentView(contentView);
        dialog.setCanceledOnTouchOutside(false);
        dialog.setCancelable(false);
    }
}

注意：我曾经在 onBackPressed() 上写了一些方法来防止对话框消失，但是，按 Back 时对话框总是消失。调试后，我意识到显示底部对话框时未达到 onBackPressed() 。我不知道为什么。

Answer 1

由于您的底部表是Fragment，因此您必须以单独的方式收听它。用这个：

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    // ...
    setupBackPressListener()
}

private fun setupBackPressListener() {
    this.view?.isFocusableInTouchMode = true
    this.view?.requestFocus()
    this.view?.setOnKeyListener { _, keyCode, _ ->
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            // Do what you want to do on back press
            true
        } else
            false
    }
}

Answer 2

这将覆盖底部工作表片段的默认 onbackpress，因此，如果您将其添加到底部工作表片段并将其留空，则当您按后退按钮时不会发生任何情况。

override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
    return object : BottomSheetDialog(requireContext(), theme) {
        override fun onBackPressed() {
            // Handle backpress in here
        }
    }
}