ExpandableListView的使用

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发布于 2019-03-01 09:42:57

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发布于 2019-03-01 09:42:57

文章被收录于专栏：刘晓杰刘晓杰

ExpandableListView组件是android中一个比较常用的组件，当点击一个父item的时候可以将它的子item显示出来，像手机QQ中的好友列表就是实现的类似效果。使用ExpandableListView组件的关键就是设置它的adapter，这个adapter必须继承BaseExpandbaleListAdapter类，所以实现运用ExpandableListView的核心就是学会继承这个BaseExpanableListAdapter类。

MainActivity.java

package com.example.expandablelistview;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.TextView;

public class MainActivity extends Activity {
	private ExpandableListView listView;
	
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        listView = (ExpandableListView)findViewById(R.id.expandableListView1);
        listView.setAdapter(new MyExpandableAdapter());
    }
    
    class MyExpandableAdapter extends BaseExpandableListAdapter{
    	private String[] groups = {"好友", "扣丁学堂"};
    	private String[][] childs = {{"猪哥", "蛋蛋"}, {"威哥", "阿珂"}};

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

		@Override
		public Object getChild(int index1, int index2) {
			return childs[index1][index2];
		}

		@Override
		public long getChildId(int index1, int index2) {
			return index2;
		}

		@Override
		public View getChildView(int index1, int index2, boolean arg2, 
				View view, ViewGroup parent) {
			if(view == null){
				view = getLayoutInflater().inflate(R.layout.child, parent, false);
			}
			TextView tv = (TextView)view.findViewById(R.id.title);
			tv.setText(childs[index1][index2]);
			return view;
		}

		@Override
		public int getChildrenCount(int index) {
			return childs[index].length;
		}

		@Override
		public long getCombinedChildId(long arg0, long arg1) { return 0; }

		@Override
		public long getCombinedGroupId(long arg0) { return 0; }

		@Override
		public Object getGroup(int index) {
			return groups[index];
		}

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

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

		@Override
		public View getGroupView(int index, boolean arg1, View view, 
				ViewGroup parent) {
			if(view == null){
				view = getLayoutInflater().inflate(R.layout.group, parent, false);
			}
			TextView tv = (TextView)view.findViewById(R.id.title);
			tv.setText(groups[index]);
			return view;
		}

		@Override
		public boolean hasStableIds() {
			// TODO Auto-generated method stub
			return false;
		}

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

main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:baselineAligned="false"
    tools:context="com.example.expandablelistview.MainActivity" >

    <ExpandableListView
        android:id="@+id/expandableListView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ExpandableListView>

</LinearLayout>

group.xml

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

    <ImageView
        android:contentDescription="@null"
        android:id="@+id/icon"
        android:maxWidth="60sp"
        android:maxHeight="60sp"
        android:adjustViewBounds="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:id="@+id/title"
        android:textSize="40sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

child.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    android:gravity="left"
    android:paddingLeft="30sp"
    tools:context=".MainActivity" >

    <ImageView
        android:contentDescription="@null"
        android:id="@+id/icon"
        android:maxWidth="60sp"
        android:maxHeight="60sp"
        android:adjustViewBounds="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:id="@+id/title"
        android:textSize="40sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

效果图：