用ExpandableListView实现类似QQ好友列表

ExpandableListView是一个用来显示二级节点的listview。

qq好友列表中子列表上下移动时，父节点在顶端会始终显示，这里我们可以自定义一个view来充当这个父节点。

 

主布局文件qq_listview如下,其中当我们拖动列表时，系统默认拖动过程中列表背景是黑的，我们可以通过android:cacheColorHint="#00000000"将其设置为透明，其中前两位是透明效果参数（00-99），后六位是颜色的设置。

 

<?xml version="1.0" encoding="utf-8"?><LinearLayout  xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="fill_parent"  android:layout_height="wrap_content"  android:orientation="vertical"  android:background="@drawable/default_bg_hdpi">  <LinearLayout   android:id="@+id/gone_linear"  android:layout_width="fill_parent"  android:layout_height="wrap_content"  android:background="@drawable/expand_column_bg"  android:visibility="gone"  android:cacheColorHint="#50000000"  >  <ImageView android:id="@+id/qq_list_imageview"   android:layout_width="wrap_content"  android:layout_height="30dip"   android:src="@drawable/narrow_select" />  <TextView android:id="@+id/qq_list_textview"   android:layout_marginLeft="50dip"  android:layout_width="fill_parent" android:layout_height="wrap_content" />  </LinearLayout><FrameLayout android:layout_width="fill_parent"android:layout_height="fill_parent">  <ExpandableListView android:id="@+id/qq_listview"  android:cacheColorHint="#00000000"  android:layout_width="fill_parent" android:layout_height="wrap_content" />  </FrameLayout></LinearLayout>

如果我们想更换父节点打开和关闭时的箭头，可以先设置一个selector.xml

 

<?xml version="1.0" encoding="utf-8"?><selector xmlns:android="http://schemas.android.com/apk/res/android"><item android:state_window_focused="false" android:drawable="@drawable/expand_column_bg_over" /><item android:state_pressed="true" android:drawable="@drawable/expand_column_bg" /><item android:state_pressed="false" android:drawable="@drawable/feedlistdividerbg"></item></selector>

 然后在代码中调用

 

elistview = (ExpandableListView)findViewById(R.id.qq_listview);//替换ExpandableListView的打开关闭时的箭头图标elistview.setGroupIndicator(this.getResources().getDrawable(R.drawable.expand_list_selector));

此外，我们还要设置父节点和子节点item的布局文件

父节点qq_list_parent.xml如下

 

<?xml version="1.0" encoding="utf-8"?><LinearLayout  xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="fill_parent"  android:layout_height="fill_parent"   android:background="@drawable/expand_column_bg">  <TextView android:id="@+id/parend"  android:layout_width="wrap_content"   android:layout_height="30dip"  android:layout_marginLeft="50dip"   /></LinearLayout>

 

子节点qq_listview_child.xml

 

<?xml version="1.0" encoding="utf-8"?><LinearLayout  xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="fill_parent"  android:layout_height="fill_parent"  android:cacheColorHint="#00000000" >    <TextView android:id="@+id/child"  android:layout_width="wrap_content" android:layout_height="40dip"  android:layout_marginLeft="80dip"  /></LinearLayout>

java代码如下

 

package com.sy.android.qqlistview;import java.util.ArrayList;import java.util.HashMap;import java.util.Map;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.AbsListView;import android.widget.AbsListView.OnScrollListener;import android.widget.ExpandableListView;import android.widget.ExpandableListView.OnGroupCollapseListener;import android.widget.ExpandableListView.OnGroupExpandListener;import android.widget.LinearLayout;import android.widget.SimpleExpandableListAdapter;import android.widget.TextView;import com.sy.android.testAndroid.R;public class QQListView extends Activity   {private static ArrayList<Map<String,String>> parentData = new ArrayList<Map<String,String>>();private static ArrayList<ArrayList<Map<String,String>>> childData = new ArrayList<ArrayList<Map<String,String>>>();private ExpandableListView elistview;private TextView tv;/** *当前打开的父节点 */private int the_group_expand_position=-1;/** * 打开的父节点所与的子节点数 */private int position_child_count=0;/** * 是否有打开的父节点 */private boolean isExpanding=false;public void getData(){for(int i=0; i<20;i++){ Map<String,String> map = new HashMap<String,String>(); map.put("parend", i+""); parentData.add(map);}for(int i=0;i<20;i++){ArrayList<Map<String,String>> child = new ArrayList<Map<String,String>>();for(int j=0; j<20;j++){Map<String,String> map = new HashMap<String,String>();map.put("child", i+""+j);child.add(map);}childData.add(child);}}public void onCreate(Bundle saveBundle){super.onCreate(saveBundle);setContentView(R.layout.qq_listview);elistview = (ExpandableListView)findViewById(R.id.qq_listview);//替换ExpandableListView的打开关闭时的箭头图标elistview.setGroupIndicator(this.getResources().getDrawable(R.drawable.expand_list_selector));tv = (TextView)findViewById(R.id.qq_list_textview);/** * 滑动子列表时在上方显示父节点的view */final LinearLayout linear = (LinearLayout)findViewById(R.id.gone_linear);/** * 监听父节点打开的事件 */elistview.setOnGroupExpandListener(new OnGroupExpandListener(){@Overridepublic void onGroupExpand(int groupPosition) {the_group_expand_position=groupPosition;position_child_count=childData.get(groupPosition).size();isExpanding=true;}});/** * 监听父节点关闭的事件 */elistview.setOnGroupCollapseListener(new OnGroupCollapseListener(){@Overridepublic void onGroupCollapse(int groupPosition) {if(linear.getVisibility()==View.VISIBLE){linear.setVisibility(View.GONE);}isExpanding=false;}});linear.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View v) {linear.setVisibility(View.GONE);elistview.collapseGroup(the_group_expand_position);}});/** * 通过setOnScrollListener来监听列表上下滑动时item显示和消失的事件 */elistview.setOnScrollListener(new OnScrollListener(){@Overridepublic void onScrollStateChanged(AbsListView view, int scrollState) {}@Overridepublic void onScroll(AbsListView view, int firstVisibleItem,int visibleItemCount, int totalItemCount) {if(isExpanding){// 当当前第一个item id小于打开的父节点id 或大于打开的父节点id和它的子节点总数之和时if(firstVisibleItem<the_group_expand_position ||firstVisibleItem>(the_group_expand_position+position_child_count)){linear.setVisibility(View.GONE);}else{linear.setVisibility(View.VISIBLE);tv.setText(((Map)parentData.get(the_group_expand_position)).get("parend").toString());}}}});getData();SimpleExpandableListAdapter selAdapter = new SimpleExpandableListAdapter(this,parentData,R.layout.qq_listview_parend_item,new String[]{"parend"},new int[]{R.id.parend},childData,R.layout.qq_liatview_child_item,new String[]{"child"},new int[]{R.id.child});elistview.setAdapter(selAdapter);}}

实现的思路是通过setOnScrollListener来监听listview，从而获得显示在视图中的item的id,通过id的判断来决定显示在顶端的自定义的view是否显示

转载于：http://syab11.iteye.com/blog/987708