java - android studio ExpandableListAdapter 上下文错误

Question

这是我的 ListAdapter 编码，我的错误出在 png 图像文件的上下文上。如果我没有错我的背景我必须改变一些东西？但我不知道要改变什么

/image/MhEWr.png

package com.example.user.myapplication;


import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;

import java.util.HashMap;
import java.util.List;

public class MyExpandableListAdapter extends BaseExpandableListAdapter {

    private Context context;
    private List<String> listGroup;
    private HashMap<String, List<String>> listChild;

    public MyExpandableListAdapter(Context context, List<String> listGroup,
                                   HashMap<String, List<String>> listChild) {
        this.context = context;
        this.listGroup = listGroup;
        this.listChild = listChild;
    }

    @Override
    public int getGroupCount() {
        return listGroup.size();
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return listChild.get(listGroup.get(groupPosition)).size();
    }

    @Override
    public Object getGroup(int groupPosition) {
        return listGroup.get(groupPosition);
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return listChild.get(listGroup.get(groupPosition)).get(childPosition);
    }

    @Override
    public long getGroupId(int groupPosition) {
        return groupPosition;
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    @Override
    public boolean hasStableIds() {
        return false;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
                             View convertView, ViewGroup parent) {
        if (convertView == null) {
            LayoutInflater infalInflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.group_layout, null);
        }

        String textGroup = (String) getGroup(groupPosition);

        TextView textViewGroup = (TextView) convertView
                .findViewById(R.id.group);
        textViewGroup.setText(textGroup);

        return convertView;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition,
                             boolean isLastChild, View convertView, ViewGroup parent) {
        if (convertView == null) {
            LayoutInflater infalInflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.item_layout, null);
        }

        TextView textViewItem = (TextView) convertView.findViewById(R.id.item);

        String text = (String) getChild(groupPosition, childPosition);

        textViewItem.setText(text);
        return convertView;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        // TODO Auto-generated method stub
        return false;
    }

}

Answer 1

发生错误是因为您从 fragment 启动它。使用

Hotel.this.getActivity().getApplicationContext()

像这样的一流酒店:

myExpandableListAdapter = new MyExpandableListAdapter(Hotel.this.getActivity().getApplicationContext(), groupList, childMap);