在某些Android开发群里，看到有些新手问怎么实现QQ好友列表，其实网上一搜挺多的。接触Android，也才一年的时间，大部分时间花在工作上（解bug。。。），界面上开发很少参与。自己维护的系统应用里，有个ExpandableListView的界面（其实android例子APIDemo也有类似的例子）就在这里写个Demo供新手参考。 ExpandableListView的用法：难点就是重写BaseExpandableListAdapter及提供的数据源。

下面看看继承BaseExpandableListAdapter的适配器：

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<SPAN xmlns= "http://www.w3.org/1999/xhtml" > package com.xyz.expande; import java.util.List; import android.app.AlertDialog; 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; public class ExpandAdapter extends BaseExpandableListAdapter { private Context mContext; private LayoutInflater mInflater = null ; private String[] mGroupStrings = null ; private List<List<Item>> mData = null ; public ExpandAdapter(Context ctx, List<List<Item>> list) { mContext = ctx; mInflater = (LayoutInflater) mContext .getSystemService(Context.LAYOUT_INFLATER_SERVICE); mGroupStrings = mContext.getResources().getStringArray(R.array.groups); mData = list; } public void setData(List<List<Item>> list) { mData = list; } @Override public int getGroupCount() { // TODO Auto-generated method stub return mData.size(); } @Override public int getChildrenCount( int groupPosition) { // TODO Auto-generated method stub return mData.get(groupPosition).size(); } @Override public List<Item> getGroup( int groupPosition) { // TODO Auto-generated method stub return mData.get(groupPosition); } @Override public Item getChild( int groupPosition, int childPosition) { // TODO Auto-generated method stub return mData.get(groupPosition).get(childPosition); } @Override public long getGroupId( int groupPosition) { // TODO Auto-generated method stub return groupPosition; } @Override public long getChildId( int groupPosition, int childPosition) { // TODO Auto-generated method stub return childPosition; } @Override public boolean hasStableIds() { // TODO Auto-generated method stub return false ; } @Override public View getGroupView( int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) { // TODO Auto-generated method stub if (convertView == null ) { convertView = mInflater.inflate(R.layout.group_item_layout, null ); } GroupViewHolder holder = new GroupViewHolder(); holder.mGroupName = (TextView) convertView .findViewById(R.id.group_name); holder.mGroupName.setText(mGroupStrings[groupPosition]); holder.mGroupCount = (TextView) convertView .findViewById(R.id.group_count); holder.mGroupCount.setText( "[" + mData.get(groupPosition).size() + "]" ); return convertView; } @Override public View getChildView( int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) { // TODO Auto-generated method stub if (convertView == null ) { convertView = mInflater.inflate(R.layout.child_item_layout, null ); } ChildViewHolder holder = new ChildViewHolder(); holder.mIcon = (ImageView) convertView.findViewById(R.id.img); holder.mIcon.setBackgroundResource(getChild(groupPosition, childPosition).getImageId()); holder.mChildName = (TextView) convertView.findViewById(R.id.item_name); holder.mChildName.setText(getChild(groupPosition, childPosition) .getName()); holder.mDetail = (TextView) convertView.findViewById(R.id.item_detail); holder.mDetail.setText(getChild(groupPosition, childPosition) .getDetail()); return convertView; } @Override public boolean isChildSelectable( int groupPosition, int childPosition) { // TODO Auto-generated method stub <SPAN style= "COLOR: #cc0000" > /*很重要：实现ChildView点击事件，必须返回true*/ </SPAN> return true ; } private class GroupViewHolder { TextView mGroupName; TextView mGroupCount; } private class ChildViewHolder { ImageView mIcon; TextView mChildName; </LinearLayout></SPAN></SPAN>

TextView mDetail;
}

}
</SPAN>[/mw_shl_code]

里面用到的有两个布局，GroupView（子list没展开的view）如图：
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1354586842_7926.png (28.18 KB, 下载次数: 3)

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布局group_item_layout.xml如下:

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<SPAN xmlns= "http://www.w3.org/1999/xhtml" ><SPAN xmlns= "http://www.w3.org/1999/xhtml" ><?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= "?android:attr/listPreferredItemHeight" android:orientation= "horizontal" > <TextView android:id= "@+id/group_name" android:layout_width= "wrap_content" android:layout_height= "?android:attr/listPreferredItemHeight" android:textAppearance= "?android:attr/textAppearanceMedium" android:layout_marginLeft= "35dip" android:gravity= "center_vertical" android:singleLine= "true" /> <TextView android:id= "@+id/group_count" android:layout_width= "wrap_content" android:layout_height= "?android:attr/listPreferredItemHeight" android:textAppearance= "?android:attr/textAppearanceMedium" android:layout_marginLeft= "5dip" android:gravity= "center_vertical" android:singleLine= "true" /> </LinearLayout></SPAN></SPAN>

另外一个就是ChildView，本例仿QQ好友列表，如图：
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1354587095_4168.png (53.2 KB, 下载次数: 4)

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2012-12-4 17:19 上传

布局child_item_layout.xml如下：

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<SPAN xmlns= "http://www.w3.org/1999/xhtml" ><SPAN xmlns= "http://www.w3.org/1999/xhtml" ><?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:minHeight= "@dimen/min_Height" <SPAN style= "COLOR: #ff0000" >android:descendantFocusability= "blocksDescendants" </SPAN> android:orientation= "horizontal" > <ImageButton android:id= "@+id/img" android:layout_width= "@dimen/image_width" android:layout_height= "@dimen/image_width" android:layout_marginLeft= "2dip" android:layout_marginRight= "10dip" android:layout_gravity= "center_vertical" /> <LinearLayout android:layout_width= "wrap_content" android:layout_height= "match_parent" android:descendantFocusability= "blocksDescendants" android:orientation= "vertical" > <TextView android:id= "@+id/item_name" android:layout_width= "wrap_content" android:layout_height= "0.0dip" android:gravity= "center_vertical" android:layout_weight= "1" /> <TextView android:id= "@+id/item_detail" android:layout_width= "wrap_content" android:layout_height= "0.0dip" android:gravity= "center_vertical" android:singleLine= "true" android:ellipsize= "end" android:layout_weight= "1" /> </LinearLayout> </LinearLayout></SPAN></SPAN>

适配器弄好了，ExpandableListView就用系统的，现在只剩下显示的问题啦

先来几张效果图：

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1354587973_5081.png (327.25 KB, 下载次数: 7)

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2012-12-4 17:21 上传

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主Activity如下：

onChildClick

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<SPAN xmlns= "http://www.w3.org/1999/xhtml" ><SPAN xmlns= "http://www.w3.org/1999/xhtml" > package com.xyz.expande; import java.util.ArrayList; import java.util.List; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.content.DialogInterface.OnClickListener; import android.os.Bundle; import android.view.View; import android.view.ViewGroup.LayoutParams; import android.widget.ExpandableListView; import android.widget.ExpandableListView.OnChildClickListener; public class HomeActivity extends Activity implements OnChildClickListener { private ExpandableListView mListView = null ; private ExpandAdapter mAdapter = null ; private List<List<Item>> mData = new ArrayList<List<Item>>(); private int [] mGroupArrays = new int [] { R.array.tianlongbabu, R.array.shediaoyingxiongzhuan, R.array.shendiaoxialv }; private int [] mDetailIds = new int [] { R.array.tianlongbabu_detail, R.array.shediaoyingxiongzhuan_detail, R.array.shendiaoxialv_detail }; private int [][] mImageIds = new int [][] { { R.drawable.img_00, R.drawable.img_01, R.drawable.img_02 }, { R.drawable.img_10, R.drawable.img_11, R.drawable.img_12, R.drawable.img_13, R.drawable.img_14, R.drawable.img_15, R.drawable.img_16 }, { R.drawable.img_20, R.drawable.img_21 } }; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); initData(); mListView = new ExpandableListView( this ); mListView.setLayoutParams( new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT)); setContentView(mListView); mListView.setGroupIndicator(getResources().getDrawable( R.drawable.expander_floder)); mAdapter = new ExpandAdapter( this , mData); mListView.setAdapter(mAdapter); mListView .setDescendantFocusability(ExpandableListView.FOCUS_AFTER_DESCENDANTS); mListView.setOnChildClickListener( this ); } <SPAN style= "COLOR: #ff0000" > /* * ChildView 设置 布局很可能onChildClick进不来，要在 ChildView layout 里加上 * android:descendantFocusability="blocksDescendants", * 还有isChildSelectable里返回true */ </SPAN> @Override public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) { // TODO Auto-generated method stub Item item = mAdapter.getChild(groupPosition, childPosition); new AlertDialog.Builder( this ) .setTitle(item.getName()) .setMessage(item.getDetail()) .setIcon(android.R.drawable.ic_menu_more) .setNegativeButton(android.R.string.cancel, new OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub } }).create().show(); return true ; } private void initData() { for ( int i = 0 ; i < mGroupArrays.length; i++) { List<Item> list = new ArrayList<Item>(); String[] childs = getStringArray(mGroupArrays<I>); String[] details = getStringArray(mDetailIds<I>); for ( int j = 0 ; j < childs.length; j++) { Item item = new Item(mImageIds<I>[j], childs[j], details[j]); list.add(item); } mData.add(list); } } private String[] getStringArray( int resId) { return getResources().getStringArray(resId); } }</SPAN></SPAN>

这这个demo的时候，想实现ChildView的点击事件，实现接口onChildClick，发现不进来，很尴尬。。。最后还是在网上找到答案了，第一，在适配器里isChildSelectable 必须返回true，第二，ChildView布局child_item_layout.xml最外层的layout设置个属性

细心的同学会发现 Item 是啥？也贴出来吧

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package com.xyz.expande; public class Item { private int resId; private String name; private String detail; public Item( int resId, String name, String detail) { this .resId= resId; this .name = name; this .detail = detail; } public void setImageId( int resId) { this .resId= resId; } public int getImageId() { return resId; } public void setName(String name) { this .name = name; } public String getName() { return name; } public void setDetail(String detail) { this .detail = detail; } public String getDetail() { return detail; } public String toString() { return "Item[" + resId + ", " + name + ", " + detail + "]" ; } }

源码下载： <IGNORE_JS_OP> ExpandeList.zip (670.11 KB, 下载次数: 988)

2012-12-4 17:23 上传 点击文件名下载附件
下载积分: e币 -10 元

http://www.eoeandroid.com/forum.php?mod=misc&action=attachcredit&aid=81469&formhash=2f2ef89c

原文：http://blog.csdn.net/zhouyuanjing/article/details/8254421

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