安卓学习第15课——ExpandableListView

AbsListView.LayoutParams lp=new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,64);
这句话的意思是 创建一个布局（LayoutParams）的实例 lp。
AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,64) 指定了该布局的宽和高；
-1代表LayoutParams.MATCH_PARENT，即该布局的尺寸将填满它的父控件；
-2代表LayoutParams.WRAP_CONTENT，即该布局的尺寸将为其自身内容的尺寸；
下面是BaseExpandableListAdapter的用法

<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="vertical">
   <ExpandableListView
    android:id="@+id/list"
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:childIndicator="@drawable/ic_launcher"
    />

</LinearLayout>

package com.example.expandablelistview;


import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.content.Context;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.os.Build;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //创建一个BaseExpandableListAdapter对象
        ExpandableListAdapter adapter=new BaseExpandableListAdapter(){

            int[] logos=new int[]{
                    R.drawable.p,R.drawable.z,R.drawable.t
            };
            private String[] armTypes=new String[]{
                "神族兵种","虫族兵种","人族兵种"    
            };
            private String[][] arms=new String[][]{
                    {"狂战士","龙骑士","黑暗圣堂","点兵"},
                    {"小狗","刺蛇","飞龙","自爆飞机"},
                    {"机枪兵","护士mm","幽灵"}
            };
            @Override
            public int getGroupCount() {
                return arms.length;
            }

            @Override
            public int getChildrenCount(int groupPosition) {
                
                return arms[groupPosition].length;
            }

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

            @Override
            public Object getChild(int groupPosition, int childPosition) {
                return arms[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 true;
            }

            @Override
            public View getGroupView(int groupPosition, boolean isExpanded,
                    View convertView, ViewGroup parent) {
                LinearLayout ll=new LinearLayout(MainActivity.this);
                ll.setOrientation(0);
                ImageView logo=new ImageView(MainActivity.this);
                logo.setImageResource(logos[groupPosition]);
                ll.addView(logo);
                TextView textView=getTextView();
                textView.setText(getGroup(groupPosition).toString());
                ll.addView(textView);
                return ll;
            }

            private TextView getTextView(){
                AbsListView.LayoutParams lp=new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,64);
                TextView textView=new TextView(MainActivity.this);
                textView.setLayoutParams(lp);
                textView.setGravity(Gravity.CENTER_VERTICAL|Gravity.LEFT);
                textView.setPadding(36, 0,0,0);
                textView.setTextSize(20);
                return textView;
            }
            @Override
            public View getChildView(int groupPosition, int childPosition,
                    boolean isLastChild, View convertView, ViewGroup parent) {
                TextView textView=getTextView();
                textView.setText(getChild(groupPosition,childPosition).toString());
                return textView;
            }

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

    ExpandableListView expandableView=(ExpandableListView) findViewById(R.id.list);
    expandableView.setAdapter(adapter);
    }

}