如何在 Android 中的片段内从回收器视图适配器调用自定义对话框片段

Question

我正在尝试调用我从扩展回收器视图的对话框片段适配器创建的自定义对话片段。我正在使用最新的安卓工作室和安卓x。以下代码适用于"自定义"对话框适配器

import android.app.DialogFragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import tino.varconn.com.instantecocash.R;
public class DialogSendMoneyFirst extends DialogFragment {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_send_money_first, container, false);
// Do all the stuff to initialize your custom view
return v;
}

我尝试用于调用对话框片段的以下代码

package tino.varconn.com.instantecocash;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import androidx.cardview.widget.CardView;
import androidx.fragment.app.FragmentTransaction;
import androidx.recyclerview.widget.RecyclerView;
import java.util.List;
import tino.varconn.com.instantecocash.dialogs.DialogSendMoneyFirst;
public class EcocashAdapter extends 
RecyclerView.Adapter<EcocashAdapter.MyViewHolder> {
private List<EcocashModel> itemList;
Context context;
public class MyViewHolder extends RecyclerView.ViewHolder {
public TextView title;
public ImageView img;
public CardView cardView;
public MyViewHolder(View view) {
super(view);
title = (TextView) view.findViewById(R.id.listtext);
img = (ImageView) view.findViewById(R.id.logo);
cardView = (CardView) view.findViewById(R.id.cardView);
}
}

public EcocashAdapter(List<EcocashModel> itemList) {
this.itemList = itemList;
}

@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.my_list_row, parent, false);
return new MyViewHolder(itemView);
}
@Override
public void onBindViewHolder(MyViewHolder holder, final int position) {
EcocashModel ecocashModel = itemList.get(position);
holder.title.setText(ecocashModel.getName());
holder.img.setImageResource(ecocashModel.getImage());
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (position == 0){
Toast.makeText(v.getContext(), "Send Money", Toast.LENGTH_SHORT).show();
DialogSendMoneyFirst dialog = new DialogSendMoneyFirst();
dialog.show(((AppCompatActivity)context).getFragmentManager(), "MyCustomDialog");
}
if (position == 1){
Toast.makeText(v.getContext(), "Pay Merchant", Toast.LENGTH_SHORT).show();
}
}
});

}
@Override
public int getItemCount() {
return itemList.size();
}

这是错误：

Attempt to invoke virtual method 'android.app.FragmentManagerandroidx.appcompat.app.AppCompatActivity.getFragmentManager()' on a null object reference

Answer 1

试试这个

public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.my_list_row, parent, false);
context = itemView.getContext()
return new MyViewHolder(itemView);
}

如果不工作：

1.检查您的活动是否是应用紧凑型。

2.如果要从片段调用适配器，请使用 getChildFragmentManager((

3. 如果您从 Activity 调用适配器，请使用 getSupportFragmentManager((

Answer 2

你的context是null

试试这个：

getActivity().getSupportFragmentManager()

而不是：

(AppCompatActivity)context).getFragmentManager()

Answer 3

如果你的上下文来自片段，那么你必须使用以下内容： [将上下文转换为片段活动]

dialog.show(((FragmentActivity) mContext).getSupportFragmentManager(), tag);