功能（以模擬音樂播放器各級文件夾目錄爲例）：
1、首先通過按鍵點擊事件生成首級列表目錄
2、通過點擊首級列表進行動態數據更新生成二級目錄
3、生成三級目錄後，最終在第三級目錄上進行條目的點擊事件
activity.xml 內容
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:orientation="vertical"
tools:context=".MainActivity">
<ExpandableListView
android:layout_width="200dp"
android:layout_height="350dp"
android:layout_weight="1"
android:id = "@+id/expand_ListView"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_weight="1">
<Button
android:id="@+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="onClick"
android:text="Button" />
<Button
android:id="@+id/button2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="onClick"
android:text="Button" />
<Button
android:id="@+id/button3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="onClick"
android:text="Button" />
</LinearLayout>
</LinearLayout>
組選項視圖（組列表的每一行的顯示格式）
groupitem_expend.xml
<?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="match_parent"
android:orientation="horizontal">
<ImageView
android:id="@+id/iv_tip"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
/>
<TextView
android:id="@+id/groupmedia_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="25sp"
android:layout_marginLeft="20dp"
android:text="TextView" />
</LinearLayout>
子選項的視圖（和組的差不多，少了一個指示箭頭的圖片）
childitem_expend.xml
<?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="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/childmedia_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="25sp"
android:text="TextView" />
</LinearLayout>
mainActivity.java
package com.thirdexpand;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class MainActivity extends AppCompatActivity {
String mFolderName = "我的音樂";
static String mMusicName = "喜刷刷";
String mSubFolderName = "青春";
static byte[] mFolderUid = {
1,2,3,4,5,6,7,8};
static byte[] mMediaUid = {
1,2,3,4,5,6,7,8};
static expandableAdapter expandableadapter;
static ExpandableListView expandableLv;
public static List<mediaGroup> mediagroupList = new ArrayList<>();
final static String TAG = "MainActivity---------";
static Handler handler = new Handler(){
@Override
public void handleMessage(@NonNull Message msg) {
switch (msg.what){
case 1:
expandableadapter.notifyDataSetChanged();
//expandableLv.setAdapter(expandableadapter);
break;
case 2:
expandableLv.setAdapter(expandableadapter);
break;
}
super.handleMessage(msg);
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
expandableadapter = new expandableAdapter(MainActivity.this,mediagroupList);
expandableLv = findViewById(R.id.expand_ListView);
expandableLv.setAdapter(expandableadapter);
expandableLv.setGroupIndicator(null);
expandableLv.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
return false;
}
});
expandableLv.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {
@Override
public boolean onGroupClick(ExpandableListView expandableListView, View view, int i, long l) {
if(expandableListView.isGroupExpanded(i)){
Log.i(TAG,"GroupExpanded-----"+expandableListView.isGroupExpanded(i));
expandableListView.collapseGroup(i);
}else{
expandableListView.expandGroup(i);
Log.i(TAG,"collapseGroup-----"+expandableListView.isGroupExpanded(i)+"----i: "+i);
for(int ii = 1; ii < 5; ii++) {
mediaChild mediachild = new mediaChild(mSubFolderName + i+"-"+ii, mFolderUid);
updateMediaChildItem(mediachild,i);
}
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
Message msg= new Message();
msg. what =1;
handler.sendMessage(msg);
}
},2000);
}
return true;
}
});
expandableLv.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
@Override
public boolean onChildClick(ExpandableListView expandableListView, View view, int i, int i1, long l) {
Log.i(TAG,"onChildClick-----**************"+"i: " + i+"i1: "+i1);
for(int iii = 1; iii < 5; iii ++){
mediaSecondChild mediasecondchild = new mediaSecondChild(mMusicName + i+"-"+i1+"-"+iii, mFolderUid);
updateMediaSecondChildItem(mediasecondchild,i,i1);
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
Message msg= new Message();
msg. what =1;
handler.sendMessage(msg);
}
},2000);
}
return true;
}
});
expandableLv.setOnGroupExpandListener(new ExpandableListView.OnGroupExpandListener() {
@Override
public void onGroupExpand(int i) {
Log.i(TAG,"onGroupExpand-------"+"i: "+i);
}
});
expandableLv.setOnGroupCollapseListener(new ExpandableListView.OnGroupCollapseListener() {
@Override
public void onGroupCollapse(int i) {
Log.i(TAG,"onGroupCollapse--------"+"i: "+i);
}
});
}
public static void updateMediaGroupItem(mediaGroup item){
List<mediaChild> tmpList = new ArrayList<mediaChild>();
item.childList = tmpList;
mediagroupList.add(item);
return;
}
public static void updateMediaChildItem(mediaChild item,int i ){
item.secondChildList = new ArrayList<mediaSecondChild>();
mediagroupList.get(i).childList.add(item);
}
public static void updateMediaSecondChildItem(mediaSecondChild secondChildItem, int i, int ii){
mediagroupList.get(i).childList.get(ii).secondChildList.add(secondChildItem);
}
public void onClick(View view) {
switch(view.getId()){
case R.id.button:
for(int i = 1; i < 5; i++) {
mediaGroup mediagroup = new mediaGroup(mFolderName+i, mFolderUid);
updateMediaGroupItem(mediagroup);
}
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
Message msg = new Message();
msg.what = 1;
handler.sendMessage(msg);
}
},2000);
break;
case R.id.button2:
break;
case R.id.button3:
break;
}
}
}
expandableAdapter.java
package com.thirdexpand;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Color;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.List;
public class expandableAdapter extends BaseExpandableListAdapter {
Context context;
List<mediaGroup> group;
final String TAG = "MainActivity--------expandableAdapter";
int groupId;
public expandableAdapter(Context context, List<mediaGroup> group){
this.context = context;
this.group = group;
}
@Override
public int getGroupCount() {
//return group.size();
return group!=null:group.size():0; // 此處加入判斷不爲空時返回
}
@Override
public int getChildrenCount(int groupPosition) {
return 1;
}
@Override
public Object getGroup(int groupPosition) {
return group.get(groupPosition);
}
@Override
public Object getChild(int groupPosition, int childPosition) {
return group.get(groupPosition).childList.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) {
mediaGroup mediagroup = (mediaGroup) getGroup(groupPosition);
View view = LayoutInflater.from(context).inflate(R.layout.groupitem_expend,null);
ImageView iv_tip = view.findViewById(R.id.iv_tip);
if(isExpanded){
iv_tip.setImageResource(R.drawable.down);
}else{
iv_tip.setImageResource(R.drawable.right);
}
TextView name = view.findViewById(R.id.groupmedia_name);
name.setText(mediagroup.getName());
return view;
}
private TextView getGenericView(String string) {
AbsListView.LayoutParams layoutParams = new AbsListView.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
TextView textView = new TextView(context);
textView.setLayoutParams(layoutParams);
textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
textView.setPadding(40, 20, 0, 20);
textView.setText(string);
textView.setTextColor(Color.RED);
return textView;
}
@SuppressLint("LongLogTag")
@Override
public View getChildView(final int groupPosition, final int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
final CustomExpandableListView view = new CustomExpandableListView(context);
final SecondexpandableAdapter adapter = new SecondexpandableAdapter(context,group.get(groupPosition).childList);
Log.i(TAG,"getChildView---"+"groupPosition--"+groupPosition+", childPosition: "+childPosition);
//groupId = groupPosition;
view.setAdapter(adapter);
view.setGroupIndicator(null);
view.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {
@SuppressLint("LongLogTag")
@Override
public boolean onGroupClick(ExpandableListView parent, View v, int i, long id) {
if(parent.isGroupExpanded(i)){
Log.i(TAG,"GroupExpanded-----"+parent.isGroupExpanded(i));
parent.collapseGroup(i);
}else{
parent.expandGroup(i);
Log.i(TAG,"collapseGroup-----"+parent.isGroupExpanded(i)+"----i: "+i);
for(int iii = 1; iii < 5; iii ++){
mediaSecondChild mediasecondchild = new mediaSecondChild(MainActivity.mMusicName + i+"-"+"-"+iii, MainActivity.mFolderUid);
//MainActivity.updateMediaSecondChildItem(mediasecondchild,groupId,groupPosition);
MainActivity.updateMediaSecondChildItem(mediasecondchild,groupPosition,i);
}
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
adapter.notifyDataSetChanged();
}
},2000);
}
return true;
}
});
view.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
@SuppressLint("LongLogTag")
@Override
public boolean onChildClick(ExpandableListView expandableListView, View view, int i, int i1, long l) {
Log.i(TAG,"setOnChildClickListener--------"+"i: "+i+"--i1: "+i1+"-----"+MainActivity.mediagroupList.get(groupPosition).childList.get(i).secondChildList.get(i1));
return true;
}
});
view.setOnGroupExpandListener(new ExpandableListView.OnGroupExpandListener() {
@SuppressLint("LongLogTag")
@Override
public void onGroupExpand(int i) {
Log.i(TAG,"onGroupExpand--------"+"i: "+i+"childposition: "+childPosition);
AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
(group.get(groupPosition).childList.get(i).secondChildList.size() + 1)* (int) 20);
view.setLayoutParams(lp);
// adapter.notifyDataSetChanged();
}
});
view.setOnGroupCollapseListener(new ExpandableListView.OnGroupCollapseListener() {
@SuppressLint("LongLogTag")
@Override
public void onGroupCollapse(int i) {
Log.i(TAG,"onGroupCollapse-------"+"i: "+groupPosition);
AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
(int) 20);
view.setLayoutParams(lp);
//adapter.notifyDataSetChanged();
}
});
view.setPadding(20,0,0,0);
return view;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
}
SecondexpandableAdapter.java
package com.thirdexpand;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.List;
public class SecondexpandableAdapter extends BaseExpandableListAdapter {
Context context;
List<mediaChild> child;
public SecondexpandableAdapter(Context context, List<mediaChild> child){
this.context = context;
this.child = child;
}
@Override
public int getGroupCount() {
//return child.size();
return child!=null?child.size():0;//避免出現數據空 導致奔潰的問題
}
@Override
public int getChildrenCount(int groupPosition) {
//return child.get(groupPosition).secondChildList.size();
return (child!=null && child.get(groupPosition).secondChildList!=null)?child.get(groupPosition).secondChildList.size():0;
}
@Override
public Object getGroup(int groupPosition) {
return child.get(groupPosition);
}
@Override
public Object getChild(int groupPosition, int childPosition) {
return child.get(groupPosition).secondChildList.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) {
// mediaGroup mediagroup = (mediaGroup) getGroup(groupPosition);
mediaChild mediaChild = (mediaChild) getGroup(groupPosition);
View view = LayoutInflater.from(context).inflate(R.layout.groupitem_expend,null);
ImageView iv_tip = view.findViewById(R.id.iv_tip);
if(isExpanded){
iv_tip.setImageResource(R.drawable.down);
}else{
iv_tip.setImageResource(R.drawable.right);
}
TextView name = view.findViewById(R.id.groupmedia_name);
name.setText(mediaChild.getName());
return view;
}
@Override
public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
mediaSecondChild mediasecondchild = (mediaSecondChild) getChild(groupPosition,childPosition);
View view = LayoutInflater.from(context).inflate(R.layout.childitem_expend,null);
TextView name = view.findViewById(R.id.childmedia_name);
name.setText(mediasecondchild.getName());
return view;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
}
customExpandableListview.java
package com.thirdexpand;
import android.content.Context;
import android.util.AttributeSet;
import android.widget.ExpandableListView;
public class CustomExpandableListView extends ExpandableListView {
public CustomExpandableListView(Context context) {
super(context);
}
public CustomExpandableListView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
public CustomExpandableListView(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// 解決顯示不全的問題
int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2
, MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}
}
另外三個數據類
mediaGroup.java
package com.thirdexpand;
import java.util.ArrayList;
import java.util.List;
public class mediaGroup {
private String name;
private String uid;
private byte[] Uid;
public List<mediaChild> childList;
public mediaGroup(String name, String uid, byte[] Uid){
this.name = name;
this.uid = uid;
this.Uid = Uid;
}
public mediaGroup(String name, byte[] Uid){
this.name = name;
this.Uid = Uid;
}
public String getUid() {
return uid;
}
public byte[] getUUid(){
return Uid;
}
public String getName() {
return name;
}
}
mediaChild.java
package com.thirdexpand;
import java.util.ArrayList;
import java.util.List;
public class mediaChild {
private String name;
private String uid;
private byte[] Uid;
public List<mediaSecondChild> secondChildList;
public mediaChild(String name, String uid){
this.uid = uid;
this.name = name;
}
public mediaChild(String name, byte[] Uid){
this.Uid = Uid;
this.name = name;
}
public String getUid() {
return uid;
}
public byte[] getUUid(){
return Uid;
}
public String getName() {
return name;
}
}
mediaSecondChild.java
package com.thirdexpand;
public class mediaSecondChild {
private String name;
private byte[] uid;
public mediaSecondChild(String name, byte[] uid){
this.uid = uid;
this.name = name;
}
public byte[] getUid() {
return uid;
}
public String getName() {
return name;
}
}