在Recylerview适配器类中，我正在arraylist中添加项，并希望在另一个Recylervew适配器类中使用它

Question

我正在将数据添加到addToSepetims数组列表中，我想在另一个片段中使用它，但我无法获得此数组列表

public class productAdapter extends RecyclerView.Adapter<productAdapter.ViewHolder> {
ArrayList<product_bilgileri> product_bilgileris = new ArrayList<product_bilgileri>();
LayoutInflater layoutInflater;
Context context;
ArrayList<AddToSepetim> addToSepetims = new ArrayList<AddToSepetim>();

public productAdapter(ArrayList<product_bilgileri> product_bilgileris, Context context) {
this.product_bilgileris = product_bilgileris;
this.context = context;
}
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
holder.productName.setText(product_bilgileris.get(position).getProductname());
holder.description.setText(product_bilgileris.get(position).getDescription());
holder.imageView.setImageDrawable(context.getResources().getDrawable(product_bilgileris.get(position).getImage()));
holder.ratingBar.setRating((product_bilgileris.get(position).getRating()));
holder.button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String a =holder.productName.getText().toString();
String b =holder.description.getText().toString();
int c = R.drawable.iphone5;
//Toast.makeText(context, ""+a, Toast.LENGTH_SHORT).show();
addToSepetims.add(new AddToSepetim(a,b,c));

}
});
}

这是我想要使用addToSepetims数组列表的地方：

public class SepetimFragment extends Fragment {

RecyclerView recyclerView;
ArrayList<AddToSepetim> addToSepetims = new ArrayList<AddToSepetim>();
public SepetimFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {

// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_sepetim, container, false);
recyclerView = view.findViewById(R.id.products_recylerview);
LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
layoutManager.setReverseLayout(true);
layoutManager.setStackFromEnd(true);
recyclerView.setLayoutManager(layoutManager);
SepetimAdapter sepetimAdapter = new SepetimAdapter(addToSepetims,getActivity());
recyclerView.setAdapter(sepetimAdapter);
return view;
}
}

我还有SepetimAdapter类

public class SepetimAdapter extends RecyclerView.Adapter<SepetimAdapter.ViewHolder> {
ArrayList<AddToSepetim> addToSepetims = new ArrayList<AddToSepetim>();
LayoutInflater layoutInflater;
public SepetimAdapter(ArrayList<AddToSepetim> addToSepetims, Context context) {
this.addToSepetims = addToSepetims;
this.context = context;
}
Context context;
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
layoutInflater = LayoutInflater.from(context);
View view = layoutInflater.inflate(R.layout.row_product_sepetim,parent,false);
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
holder.productName.setText(addToSepetims.get(position).getProductname());
holder.description.setText(addToSepetims.get(position).getDescription());
holder.imageView.setImageDrawable(context.getResources().getDrawable(addToSepetims.get(position).getImage()));
holder.button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//                addToSepetims.remove(addToSepetims.get(position));
}
});
}
@Override
public int getItemCount() {
return addToSepetims.size();
}

public class ViewHolder extends RecyclerView.ViewHolder {
TextView productName,description;
ImageView imageView;
Button button;
public ViewHolder(@NonNull View itemView) {
super(itemView);
productName = itemView.findViewById(R.id.product_Name);
description = itemView.findViewById(R.id.descripton);
imageView = itemView.findViewById(R.id.product_pic);
button  = itemView.findViewById(R.id.deleteFromCard);
}
}
}

第二个问题：

onBindViewHolder类中的产品适配器类：

int c = R.drawable.iphone5;

在这一行中，我想要获得holder.imageView而不是"；R.drawable.iphone5"；我该怎么做？

Answer 1

您可以通过ViewModel:在片段之间共享数据

1. 在build.gradle(模块：应用程序(级别中添加依赖项

implementation "androidx.lifecycle:lifecycle-viewmodel:2.2.0"
implementation "android.arch.lifecycle:runtime:2.2.0"

2. 创建从AndroidViewModel扩展的自定义ViewModel类

此处添加了要在片段之间共享的列表。

public class MainViewModel extends AndroidViewModel {
private ArrayList<product_bilgileri> products;
public TempViewModel(@NonNull Application application) {
super(application);
}
public ArrayList<product_bilgileri> getProducts() {
return products;
}
public void setProducts(ArrayList<product_bilgileri> products) {
this.products = products;
}
}

3. 在活动/片段中实例化ViewModel实例

// In activity 
MainViewModel mViewModel = new ViewModelProvider(this).get(MainViewModel.class);
// In fragment
MainViewModel mViewModel = new ViewModelProvider(requireActivity()).get(MainViewModel.class);

然后用mViewModel.setProducts(myList)设置数据列表，并用mViewModel.getProducts()检索

有关更多信息，请查看文档。还要查看这篇文章。