这两天在捣鼓ListView widget,为了在ListView中加入Button这类的有 “点击” 事件的widget,请教了不少高手,感谢LandMark对我的认真讲解,下面把解决过程描述一下。
ListView 和 其它能触发点击事件的widget无法一起正常工作的原因是加入其它widget后,ListView的itemclick事件将无法触发,被其它widget的click事件屏蔽。
- 首先,说明一下,ListView中每一行包括以下三项:
一个ImageView, 一个TextView,一个ImageButton,依次排开。
以下是layout的内容,分为两部分:
<?xmlversion="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:padding="10dip" android:orientation="vertical">
<ListView android:id="@id/android:list" android:layout_width="fill_parent"
android:layout_height="fill_parent"/> </LinearLayout>
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因为继承了ListActivity,所以ListView 的id设置为"@id/android:list"是必须的
注意:
在<RelativeLayout>中
android:descendantFocusability="blocksDescendants"
和<ImageButton>中
android:focusable="false"
这两项的设置很关键,如果不设置,将导致ListView的ItemClick事件将无法触发,该事件被ImageButton的click事件屏蔽了。
<?xmlversion="1.0"encoding="utf-8"?> <RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:padding="5dip"
android:descendantFocusability="blocksDescendants">
<ImageView
android:id="@+id/ItemImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="5dip"
/>
<!--
把按钮背景设置为透明: android:background="#00000000"
把按钮背景设置为半透明: android:background="#e0000000"
-->
<ImageButton
android:id="@+id/ItemCloseWin"
android:layout_alignParentRight="true"
android:layout_alignTop="@+id/ItemWinName"
android:layout_alignBottom="@+id/ItemWinName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#e0000000"
android:gravity="left|center_vertical"
android:focusable="false"
android:src="@android:drawable/ic_menu_close_clear_cancel"
/>
<TextView
android:id="@+id/ItemWinName"
android:layout_toRightOf="@+id/ItemImage"
android:layout_toLeftOf="@+id/ItemCloseWin"
android:layout_alignTop="@+id/ItemImage"
android:layout_alignBottom="@+id/ItemImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="left|center_vertical"
android:textSize="20dip"
android:text="title"
/>
</RelativeLayout>
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- 接下来,我们看看继承ListActivity的实现
在lvWithButtonExt中,为了能处理ImageButton的click事件,我继承了BaseAdapter类,并重新实现了getView()接口,在其中加入了Button的clicklistener,详见lvButtonAdapter类的实现。
publicclass lvWithButtonExt
extends ListActivity
{
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 关联Layout中的ListView
ListView vncListView
= (ListView)findViewById(android.R.id.list);
// 生成动态数组,加入数据
ArrayList<HashMap<String,Object>>
remoteWindowItem=
new ArrayList<HashMap<String,Object>>();
for(int i=0;i<10;i++)
{
HashMap<String,Object>
map =
newHashMap<String,Object>();
map.put("ItemImage", R.drawable.firefox);//图像资源的ID
map.put("ItemWinName","Window
ID "+i);
map.put("ItemCloseWin", android.R.drawable.ic_menu_close_clear_cancel);
remoteWindowItem.add(map);
}
// 生成适配器的Item和动态数组对应的元素
lvButtonAdapter listItemAdapter =
new lvButtonAdapter(
this,
remoteWindowItem,//数据源
R.layout.lvitem,//ListItem的XML实现
//动态数组与ImageItem对应的子项
new String[]{"ItemImage","ItemWinName","ItemCloseWin"},
//ImageItem的XML文件里面的一个ImageView,两个TextView ID
new int[]{R.id.ItemImage,R.id.ItemWinName,R.id.ItemCloseWin}
);
vncListView.setAdapter(listItemAdapter);
}
@Override
protected void onListItemClick(ListView l,View
v, int
position,long
id){
// TODO Auto-generated method stub
super.onListItemClick(l, v,position,
id);
l.getItemAtPosition(position);
} }
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- 接下来,我们看看lvButtonAdapter的实现
为了响应按钮的点击事件,首先要记录按钮的位置,然后为按钮设置clicklistener。
在重新实现的getView()接口中,我使用了lvButtonListener监听类,在构造函数中,记录行号,以便在OnClick接口中能准确的定位按钮所在的位置,进而对相应的行进行处理。
publicclass lvButtonAdapter
extends BaseAdapter
{
private class buttonViewHolder{
ImageView appIcon;
TextView appName;
ImageButton buttonClose;
}
private ArrayList<HashMap<String,Object>>
mAppList;
private LayoutInflater mInflater;
private Context mContext;
private String[] keyString;
private int[] valueViewID;
private buttonViewHolder holder;
public lvButtonAdapter(Context c,ArrayList<HashMap<String,Object>>
appList,int resource,
String[]from,
int[] to){
mAppList = appList;
mContext = c;
mInflater =
(LayoutInflater)mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
keyString =
new String[from.length];
valueViewID =
new int[to.length];
System.arraycopy(from, 0,
keyString, 0,from.length);
System.arraycopy(to, 0, valueViewID,
0, to.length);
}
@Override
public intgetCount(){
return mAppList.size();
}
@Override
public ObjectgetItem(intposition)
{
return mAppList.get(position);
}
@Override
public long getItemId(intposition)
{
return position;
}
public voidremoveItem(intposition){
mAppList.remove(position);
this.notifyDataSetChanged();
}
@Override
public ViewgetView(intposition,
View convertView, ViewGroup
parent)
{
if (convertView!=
null)
{
holder =
(buttonViewHolder) convertView.getTag();
} else{
convertView = mInflater.inflate(R.layout.lvitem,null);
holder =
new buttonViewHolder();
holder.appIcon
= (ImageView)convertView.findViewById(valueViewID[0]);
holder.appName
= (TextView)convertView.findViewById(valueViewID[1]);
holder.buttonClose
= (ImageButton)convertView.findViewById(valueViewID[2]);
convertView.setTag(holder);
}
HashMap<String,Object> appInfo=
mAppList.get(position);
if (appInfo!=
null)
{
String aname
= (String) appInfo.get(keyString[1]);
int mid
= (Integer)appInfo.get(keyString[0]);
int bid
= (Integer)appInfo.get(keyString[2]);
holder.appName.setText(aname);
holder.appIcon.setImageDrawable(holder.appIcon.getResources().getDrawable(mid));
holder.buttonClose.setImageDrawable(holder.buttonClose.getResources().getDrawable(bid));
holder.buttonClose.setOnClickListener(new lvButtonListener(position));
}
return convertView;
}
class lvButtonListener
implements OnClickListener {
private intposition;
lvButtonListener(int pos){
position
= pos;
}
@Override
public void onClick(View v){
int vid=v.getId();
if (vid== holder.buttonClose.getId())
removeItem(position);
}
} }
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以下是运行效果图:
点击右边的按钮该行将被删除
出处:http://blog.chinaunix.net/u3/111168/showart_2418981.html
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