Android 二级列表

请求网络数据二级列表的GitHub地址：点击打开链接 

https://github.com/zhouxua/Erji_liebiao

//适配器

public class MyExpandableListView extends BaseExpandableListAdapter {
    private Context context;
    private LayoutInflater inflater;

    public MyExpandableListView(Context context){
        this.context = context;
        inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }
    private String[] groups = {"A", "B", "C"};
    //注意，字符数组不要写成{{"A1,A2,A3,A4"}, {"B1,B2,B3,B4，B5"}, {"C1,C2,C3,C4"}}*/
    private String[][] childs={{"A1","A2","A3","A4"},{"A1","A2","A3", "B4"},{"A1","A2","A3","C4"}};

    //返回一级列表的个数
    @Override
    public int getGroupCount() {
        return groups.length;
    }

    //返回每个二级列表的个数
    @Override
    public int getChildrenCount(int groupPosition) { //参数groupPosition表示第几个一级列表
        Log.d("smyhvae", "-->" + groupPosition);
        return childs[groupPosition].length;
    }

    //返回一级列表的单个item（返回的是对象）
    @Override
    public Object getGroup(int groupPosition) {
        return groups[groupPosition];
    }

    //返回二级列表中的单个item（返回的是对象）
    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return childs[groupPosition][childPosition];  //不要误写成groups[groupPosition][childPosition]
    }

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

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

    //每个item的id是否是固定？一般为true
    @Override
    public boolean hasStableIds() {
        return true;
    }

    //【重要】填充一级列表
    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {

        if (convertView == null) {
            convertView = inflater.inflate(R.layout.item_group, null);
        }
        TextView tv_group = (TextView) convertView.findViewById(R.id.tv_group);
        tv_group.setText(groups[groupPosition]);
        return convertView;
    }

    //【重要】填充二级列表
    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {

        if (convertView == null) {
            convertView = inflater.inflate(R.layout.item_child, null);
        }

        ImageView iv_child = (ImageView) convertView.findViewById(R.id.iv_child);
        TextView tv_child = (TextView) convertView.findViewById(R.id.tv_child);

        //iv_child.setImageResource(resId);
        tv_child.setText(childs[groupPosition][childPosition]);

        return convertView;
    }

    //二级列表中的item是否能够被选中？可以改为true
    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }
}

//mainactivity中

public class MainActivity extends AppCompatActivity {
    //View
    private ExpandableListView expandableListView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        expandableListView = (ExpandableListView) findViewById(R.id.expandableListView);

        expandableListView.setAdapter(new MyExpandableListView(MainActivity.this));

    }
}