Android--ListView中添加控件的点击

时间:2021-10-09 19:38:35

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:

res/layout/main.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:padding="10dip" android:orientation="vertical">


<ListView android:id="@id/android:list" android:layout_width="fill_parent"
android:layout_height="fill_parent" />

</LinearLayout>

因为继承了ListActivity,所以ListView 的id设置为”@id/android:list”是必须的res/layout/lvitem.xml
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。

<?xml version="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>

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。

public class 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 = newArrayList<HashMap<String, Object>>();
for(int i=0;i<10;i++)
{
HashMap<String, Object> map = new HashMap<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);
}
}

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。

public class 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 int getCount() {
return mAppList.size();
}

@Override
public Object getItem(int position) {
return mAppList.get(position);
}

@Override
public long getItemId(int position) {
return position;
}

public void removeItem(int position){
mAppList.remove(position);
this.notifyDataSetChanged();
}

@Override
public View getView(int position, 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 int position;

lvButtonListener(int pos) {
position = pos;
}

@Override
public void onClick(View v) {
int vid=v.getId();
if (vid == holder.buttonClose.getId())
removeItem(position);
}
}
}