简单的学习使用ExpandableListview

简单的学习使用ExpandableListview

一、Activity

我这里使用List<String[]>,一般使用的是List<List<String>>
实现的是二级列表展示效果

package com.ahtelit.zbv.myapplication;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ExpandableListView;

import java.util.ArrayList;
import java.util.List;

public class Main4Activity extends AppCompatActivity {

    private ExpandableListView expandableListView;
    private String[] parents={"语言","爱好"};
    private ArrayList<String[]> childs;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main4);
        expandableListView=findViewById(R.id.expandale_lv);

        childs=new ArrayList<String[]>();

        childs.add(new String[]{"java","c","javascript"});

        childs.add(new String[]{"写作","欣赏","玩游戏"});

        expandableListView.setAdapter(new ExLVAdapter(this,childs,parents));


    }
}

2、EXAdapter

需要一级层级的布局和二级层级的布局两份即可

package com.ahtelit.zbv.myapplication;

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

import java.util.ArrayList;
import java.util.List;

/**
 * Created by Administrator on 2018/4/25.
 * qzx
 */

public class ExLVAdapter extends BaseExpandableListAdapter {

    private Context mContext;
    private List<String[]> childDatas;
    private String[] parentDatas;
    public ExLVAdapter(Context context, ArrayList<String[]> childList,String[] parentList){
        mContext=context;
        childDatas=childList;
        parentDatas=parentList;
    }

    @Override
    public int getGroupCount() {
        return parentDatas.length;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return childDatas.size();
    }

    @Override
    public Object getGroup(int groupPosition) {
        return parentDatas[groupPosition];
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {

        return childDatas.get(groupPosition)[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) {

        View view= LayoutInflater.from(mContext).inflate(R.layout.left_item_layout,parent,false);

        TextView tv=(TextView) view.findViewById(R.id.tv);

        tv.setText(parentDatas[groupPosition]);

        return view;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        View view= LayoutInflater.from(mContext).inflate(R.layout.left_item_layout,parent,false);

        TextView tv=(TextView) view.findViewById(R.id.tv);

        tv.setText(childDatas.get(groupPosition)[childPosition]);
        return view;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return false;
    }
}

3、xml布局文件

1、Activity布局

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.ahtelit.zbv.myapplication.Main4Activity">

    <ExpandableListView
        android:id="@+id/expandale_lv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"></ExpandableListView>

</android.support.constraint.ConstraintLayout>

2、expandableListview布局

我一级布局和二级布局都一样的都是简单的TextView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="left">

    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="七子笑"
        />

</LinearLayout>