如何将不同的点击从 DialogFragment 回调到 Activity？

Question

我有一个带有 RecyclerView 的 DialogFragment，我可以在其中单击一些项目，这些项目必须从 Activity 添加到“父”项目，并且我还有其他 4 个按钮在该对话框中执行不同的操作。

如何管理来自 RecyclerView 和 Activity 中按钮的点击？

就像我的对话框是这样的：

@NonNull
@Override
public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
    AlertDialog.Builder builder = new AlertDialog.Builder(requireActivity());

    final Comanda prodotto = (Comanda) getArguments().getSerializable("PRODOTTO");
    final int menuSelezionato = getArguments().getInt("ACTIVE_MENU");

    List<Varianti> variantiAggiunte = prodotto.getVarianti();


    DataBaseHandler dbContext = DataBaseHandler.getInstance(requireActivity());
    ArrayList<VariantiBinding> variantiList = dbContext.getVarianti();
    ArrayList<VariantiBinding> variantiFilteredList = selectVariantiByMenu(variantiList, menuSelezionato);

    AdapterVariantiAggiunte adapterVariantiAggiunte = aggiunteRecycler(recyclerVariantiAdded, variantiAggiunte);
    AdapterVarianti adapterVarianti = variantiRecycler(recyclerVarianti, variantiFilteredList);

    title.setText(prodotto.getDescrizione());

    builder.setView(view);

    adapterVarianti.setOnItemClickListener(positionVariante -> {
        search.clearFocus();
        VariantiBinding varianteSelezionata = adapterVarianti.getList().get(positionVariante);
        Varianti variante = getVariante(varianteSelezionata);
        if (variante != null) {
            //adapterComanda.addVariante(variante); adapterComanda is in Activity
            adapterVariantiAggiunte.notifyItemInserted(adapterVariantiAggiunte.getItemCount() - 1);
            recyclerVariantiAdded.scrollToPosition(adapterVariantiAggiunte.getItemCount() - 1);
        }
    });
    
    return builder.create();
}

我必须在 VariantiDialog 和 My Activity 中处理adapterVarianti 点击，现在只处理 Dialog 中的点击，但就像我需要在我的 Activity 中获得回调之类的东西并调用：

adapterComanda.addVariante(variante);

在所有这些都处于同一级别之前，但我的所有 AlertDialogs 都在我的 Activity 中，我正在将它们移动到 DialogFragment。

Answer 1

您可以使用接口来提供回调，一个用于对话框片段到活动，一个从回收器视图到对话框片段

1接口（用于从对话片段回调到活动）

public interface OnDialogCountryChangeListener {
    public void onDialogCountryChange(String country);
}

2 Activity.java（开始对话片段的类）

public class MyActivity extends AppCompactActivity implements OnDialogCountryChangeListener {
    
    ...

    private void showDialog() {
        FragmentManager fm = getSupportFragmentManager();
        CountryDialogFragment countryDialog = new CountryDialogFragment();
        countryDialog.setTargetFragment(this, 0); // set target fragment for callback listener
        countryDialog.show(fm, "add_dialog");
    }

    @Override
    public void onDialogCountryChange(String country) {
        // Your callback from dialog fragment to activity
        // Do your stuff
    }
}

3 CountryDialogFragment.java

 @Override
public void onAttach(@NonNull Context context) {
    super.onAttach(context);

       try {
            countryActivitycallback = (OnDialogCountryChangeListener) getTargetFragment(); // callback instance 
        } catch (ClassCastException e) {
            throw new ClassCastException("Calling Fragment must implement OnDialogCountryChangeListener"); 
        }
 }

---

用于从 recyclerview 回调到对话框片段

1创建界面（您也可以使用相同的界面，但我认为最好使用新的不同的界面来解释，因为它可能会变得混乱）

public interface OnItemClickListener {
     void onItemClick(String countryItem);
 }

2接下来修改您的 Adapter 类，在您的情况下为 RecycleView Adapter

i) 在构造函数中将侦听器作为参数发送

private final OnItemClickListener listener;
public RecycleViewCountryAdapter(OnItemClickListener listener) {
         this.listener = listener;
     }

ii) 在 ViewHolder 类中的某个视图上设置 onCLick 监听器

public MyViewHolder(View itemView) {
         super(itemView);
         imageOnCard = (ImageView) itemView.findViewById(R.id.image_on_cardview);
         // change your listener on any other view if you want
         imageOnCard..setOnClickListener(new View.OnClickListener() {
                 @Override public void onClick(View v) {
                       listener.onItemClick(worldDataModelArrayList.get(getAdapterPosition()));
                 }
        });

     }

3现在修改你的DialogFragment类来监听你的接口回调，

 recyclerView.setLayoutManager(new LinearLayoutManager(this.getContext()));
 RecycleViewCountryAdapter adapter = new RecycleViewCountryAdapter(new OnItemClickListener() {
     @Override public void onItemClick(String countryItem) {
        // implement click listener as per your requirement

       // handle your work in dialog fragment and also give callback to activity
     if(countryActivitycallback!=null) // callback for activity
       {
                countryActivitycallback.onDialogCountryChange(countryItem);
        }

     });
 recyclerView.setAdapter(adapter);

编辑： setTargetFragment 现已弃用。作为一种替代方式，您可以使用共享 ViewModel 或使用新 API FragmentResultListener 执行相同操作。