入门篇ExpandableListAdapter（简易树形组件）

package org.lxh.demo;

/*实现简单的树形组件

*可以以我的代码为参考进行优化得到更好看的

*/

import android.content.Context;

import android.view.Gravity;

import android.view.View;

import android.view.ViewGroup;

import android.widget.AbsListView;

import android.widget.BaseExpandableListAdapter;

import android.widget.TextView;

public class MyExpandableListAdapter extends BaseExpandableListAdapter {

// 一个组下肯定会有多个子选项

private String[] groups = new String[] { "我的好友", "家人", "同事", "黑名单" };
// 组名称

private String[][] children = new String[][] {

{ "李兴华", "张三", "李四", "MLDN" }, { "父亲", "母亲" },

{ "王五", "赵六", "王八" }, { "票贩子", "造假商" } };
// 这里面定义的子选项

private Context context = null ;

public MyExpandableListAdapter(Context context) {

this.context = context ;

}

@Override

public Object getChild(int groupPosition, int childPosition) {
// 取得指定的子选项

return this.children[groupPosition][childPosition];

}

@Override

public long getChildId(int groupPosition, int childPosition) {

return childPosition;

}

private TextView buildTextView() {

AbsListView.LayoutParams params = new AbsListView.LayoutParams(

ViewGroup.LayoutParams.FILL_PARENT, 35);

TextView textView = new TextView(this.context) ;

textView.setLayoutParams(params) ;

textView.setTextSize(15.0f) ;

textView.setGravity(Gravity.LEFT) ;

textView.setPadding(40, 8, 3, 3) ;

return textView ;

}

@Override

public View getChildView(int groupPosition, int childPosition,

boolean isLastChild, View convertView, ViewGroup parent) {

TextView textView = this.buildTextView() ;

textView.setText(this.getChild(groupPosition, childPosition).toString()) ;

return textView;

}

@Override

public int getChildrenCount(int groupPosition) {

return this.children[groupPosition].length ;

}

@Override

public Object getGroup(int groupPosition) {

return this.groups[groupPosition];

}

@Override

public int getGroupCount() {

return this.groups.length;

}

@Override

public long getGroupId(int groupPosition) {

return groupPosition;

}

@Override

public View getGroupView(int groupPosition, boolean isExpanded,

View convertView, ViewGroup parent) {

TextView textView = this.buildTextView() ;

textView.setText(this.getGroup(groupPosition).toString()) ;

return textView;

}

@Override

public boolean hasStableIds() {

return true;

}

@Override

public boolean isChildSelectable(int groupPosition, int childPosition) {

return true;

}

}

package org.lxh.demo;

import android.app.Activity;

import android.os.Bundle;

import android.view.ContextMenu;

import android.view.ContextMenu.ContextMenuInfo;

import android.view.View;

import android.widget.ExpandableListAdapter;

import android.widget.ExpandableListView;

import android.widget.ExpandableListView.OnChildClickListener;

import android.widget.ExpandableListView.OnGroupClickListener;

import android.widget.ExpandableListView.OnGroupCollapseListener;

import android.widget.ExpandableListView.OnGroupExpandListener;

import android.widget.Toast;

public class MyExpandableListViewDemo extends Activity {

private ExpandableListView elistview = null;

private ExpandableListAdapter adapter = null;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

super.setContentView(R.layout.main);

this.elistview = (ExpandableListView) super

.findViewById(R.id.elistview);

this.adapter = new MyExpandableListAdapter(this);

this.elistview.setAdapter(this.adapter);

super.registerForContextMenu(this.elistview);

this.elistview.setOnChildClickListener(new OnChildClickListenerImpl());

this.elistview.setOnGroupClickListener(new OnGroupClickListenerImpl());

this.elistview

.setOnGroupExpandListener(new OnGroupExpandListenerImpl());

this.elistview

.setOnGroupCollapseListener(new OnGroupCollapseListenerImpl());

}

private class OnChildClickListenerImpl implements OnChildClickListener {

@Override

public boolean onChildClick(ExpandableListView parent, View v,

int groupPosition, int childPosition, long id) {

Toast.makeText(

MyExpandableListViewDemo.this,

"子选项被选中，groupPosition = " + groupPosition

+ "，childPosition = " + childPosition,

Toast.LENGTH_SHORT).show();

return false;

}

}

private class OnGroupClickListenerImpl implements OnGroupClickListener {

@Override

public boolean onGroupClick(ExpandableListView parent, View v,

int groupPosition, long id) {

Toast.makeText(MyExpandableListViewDemo.this,

"分组被选中，groupPosition = " + groupPosition,

Toast.LENGTH_SHORT).show();

return false;

}

}

private class OnGroupExpandListenerImpl implements OnGroupExpandListener {

@Override

public void onGroupExpand(int groupPosition) {

Toast.makeText(MyExpandableListViewDemo.this,

"打开分组，groupPosition = " + groupPosition, Toast.LENGTH_SHORT)

.show();

}

}

private class OnGroupCollapseListenerImpl implements

OnGroupCollapseListener {

@Override

public void onGroupCollapse(int groupPosition) {

Toast.makeText(MyExpandableListViewDemo.this,

"关闭分组，groupPosition = " + groupPosition, Toast.LENGTH_SHORT)

.show();

}

}

@Override

public void onCreateContextMenu(ContextMenu menu, View v,

ContextMenuInfo menuInfo) {

super.onCreateContextMenu(menu, v, menuInfo);

ExpandableListView.ExpandableListContextMenuInfo info = (ExpandableListView.ExpandableListContextMenuInfo) menuInfo;

int type = ExpandableListView

.getPackedPositionType(info.packedPosition); // 取得菜单项

int group = ExpandableListView

.getPackedPositionGroup(info.packedPosition); // 取得所在组的索引

int child = ExpandableListView

.getPackedPositionChild(info.packedPosition); // 取得子菜单项的索引

Toast.makeText(MyExpandableListViewDemo.this,

"type = " + type + "，group = " + group + "，child = " + child,

Toast.LENGTH_SHORT).show();

}

}

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

>

<ExpandableListView

android:id="@+id/elistview"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

/>

</LinearLayout>