java - 监听对话框在每个 ViewPager fragment 中单击肯定按钮

Question

我正在测试监听每个 ViewPager fragment 中的 AlertDialog 按钮单击(正和中性)的功能。我现在正在使用 Interface 方法，但遇到了一些麻烦。

所以结构是这样的，我有一个由DialogFragment创建的AlertDialog，我把一个带有两个 fragment 的ViewPager放入这个DialogFragment。我的目标是，当我单击 AlertDialog 上的 Positive 按钮时，我希望调用这两个 ViewPager fragment 中的一些方法，以便我可以收集这些 fragment 上的数据.

现在的问题是，只有第二个 fragment 响应，我不知道为什么。

代码如下:

1. 我创建了一个接口(interface)文件

   public interface Communicator {
       void onConfirmClick();
   }
   

2. 我有一个 DialogFragment

   public class MainDialogFragment extends DialogFragment {
       View dialogLayout;
       Communicator communicator;
   
       @Override
       public void onAttachFragment(Fragment childFragment) {
           communicator = (Communicator) childFragment;
       }
   
       @Nullable
       @Override
       public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
           return dialogLayout;
       }
   
       @NonNull
       @Override
       public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
           AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(getActivity());
           dialogLayout = getActivity().getLayoutInflater().inflate(R.layout.dialog_main, null);
           ViewPager viewPager = dialogLayout.findViewById(R.id.main_viewPager);
   
           final MainPagerAdapter adapter = new MainPagerAdapter(getChildFragmentManager());
           viewPager.setAdapter(adapter);
   
           dialogBuilder.setView(dialogLayout);
           dialogBuilder.setPositiveButton("Confirm", null);
           dialogBuilder.setNegativeButton("Cancel", null);
           dialogBuilder.setNeutralButton("Change", null);
   
           final AlertDialog dialog = dialogBuilder.create();
   
           dialog.setOnShowListener(new DialogInterface.OnShowListener() {
               @Override
               public void onShow(DialogInterface dialogInterface) {
                   dialog.getButton(DialogInterface.BUTTON_POSITIVE).setOnClickListener(new View.OnClickListener() {
                       @Override
                       public void onClick(View view) {
                           communicator.onConfirmClick();
                       }
                   });
   
           dialog.getButton(DialogInterface.BUTTON_NEUTRAL).setOnClickListener(new View.OnClickListener() {
                       @Override
                       public void onClick(View view) {
                           Toast.makeText(view.getContext(), "Change click!!", Toast.LENGTH_SHORT).show();
                       }
                   });
               }
           });
   
           return dialog;
       }
   }
   

3. 我的 fragment A

   public class MainFragmentA extends Fragment implements Communicator{
       View rootView;
   
       @Nullable
       @Override
       public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
           rootView = inflater.inflate(R.layout.fragment_a, container, false);
   
           return rootView;
       }
   
       @Override
       public void onConfirmClick() {
           Toast.makeText(getContext(), "Fragment A!!", Toast.LENGTH_SHORT).show();
       }
   }
   

4. 我的 fragment B

   public class MainFragmentB extends Fragment implements Communicator{
       View rootView;
   
       @Nullable
       @Override
       public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
           rootView = inflater.inflate(R.layout.fragment_b, container, false);
   
           return rootView;
       }
   
       @Override
       public void onConfirmClick() {
           Toast.makeText(getContext(), "Fragment B!!", Toast.LENGTH_SHORT).show();
       }
   }
   

5. 我的 ViewPager 适配器在 DialogFragment 中使用

   public class MainPagerAdapter extends FragmentPagerAdapter {
       public MainPagerAdapter(FragmentManager fragmentManager) {
           super(fragmentManager);
       }
   
       @Override
       public Fragment getItem(int position) {
           switch (position) {
               case 0:
                   return new MainFragmentA();
   
               case 1:
                   return new MainFragmentB();
   
               default:
                   throw new IllegalArgumentException("Wrong position!!");
           }
       }
   
       @Override
       public int getCount() {
           return 2;
       }
   }
   

6. 我的主要 Activity

   public class MainActivity extends AppCompatActivity{
       Button showDialogButton;
   
       @Override
       protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.activity_main);
   
           showDialogButton = findViewById(R.id.main_show_dialog_button);
   
           showDialogButton.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View view) {
                   MainDialogFragment mainDialogFragment = new MainDialogFragment();
                   mainDialogFragment.show(getSupportFragmentManager(), "mainDialogFragment");
               }
           });
       }
   }
   

有人可以帮忙吗？我将非常感激!!!

Answer 1

使用某种 Communicator 接口(interface)的集合，而不是单个接口(interface)。每次附加子 fragment 时，您都会覆盖communicator。

public class MainDialogFragment extends DialogFragment {
    View dialogLayout;
    List<Communicator> communicators = new ArrayList<>();

    @Override
    public void onAttachFragment(Fragment childFragment) {
        communicators.add((Communicator) childFragment);
    }

    // all the other things from the MainDialogFragment...
}

并在 BUTTON_POSITIVE 回调中迭代列表。

dialog.getButton(DialogInterface.BUTTON_POSITIVE).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
        for (Communicator communicator : communicators) { 
            communicator.onConfirmClick();
        }
    }
});