安卓開發樹形控件之ExpandableListView(一)，expandablelistview

安卓開發樹形控件之ExpandableListView(一)，expandablelistview

　　這個例子非常簡單，簡單到一個初學者都能隨便開發出來，今天的目的僅僅只是為了將效果實現出來，如果想深入這裡有幾篇非常不錯的博客：

Android 之ExpandableListView幾個特殊的屬性

http://blog.csdn.net/t12x3456/article/details/7828620

ExpandableListView講解
http://www.apkbus.com/thread-124715-1-1.html

和使用listview一樣，我們這裡需要繼承一個適配器，叫做BaseExpandListAdapter;然後重寫幾個父類的方法

package com.example.uitest;

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

public class TreeAdapter extends BaseExpandableListAdapter{

Context context;


public TreeAdapter(Context context) {
super();
this.context = context;
}

@Override
public Object getChild(int arg0, int arg1) {
return 0;
}

@Override
public long getChildId(int arg0, int arg1) {
// TODO Auto-generated method stub
return 0;
}

@Override
public View getChildView(int arg0, int arg1, boolean arg2, View v,
ViewGroup arg4) {
v = LayoutInflater.from(context).inflate(R.layout.item2, null);
return v;
}

@Override
public int getChildrenCount(int arg0) {
// TODO Auto-generated method stub
return 3;
}

@Override
public Object getGroup(int arg0) {
// TODO Auto-generated method stub
return null;
}

@Override
public int getGroupCount() {
return 3;
}

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

@Override
public View getGroupView(int arg0, boolean arg1, View v, ViewGroup vgs) {
v = LayoutInflater.from(context).inflate(R.layout.item_autocomplete, null);
return v;
}

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

@Override
public boolean isChildSelectable(int arg0, int arg1) {
// TODO Auto-generated method stub
return false;
}

}

這裡我們只操作了四個函數，分別是：

public int getChildrenCount(int arg0) ;//獲取二級列表的子布局總記錄，也就是行數

public int getGroupCount();//獲取一級列表的行數

public View getChildView(int arg0, int arg1, boolean arg2, View v,
ViewGroup arg4);//獲取二級列表的資源布局

public View getGroupView(int arg0, boolean arg1, View v, ViewGroup vgs);//獲取一級列表的行數

最後將適配器加載至ExpandableListView中：

ExpandableListView view = (ExpandableListView)findViewById(R.id.elv);
TreeAdapter adapter = new TreeAdapter(getApplicationContext());
view.setAdapter(adapter);

主布局xml：

<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" >

<ExpandableListView
android:id="@+id/elv"
android:layout_width="fill_parent"

 android:groupIndicator="@null"
android:layout_height="wrap_content"></ExpandableListView>

</LinearLayout>

這是最濃縮版了大家應該很快可以懂；