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Android: ListView与Button的共存问题解决

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>

res/layout/lvitem.xml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。

  • <?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>

    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。接下来,我们看看继承ListActivity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);    }}

  • 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。接下来,我们看看lvButtonAdapter的实现

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);        }    }}


点击右边的按钮该行将被删除以下是运行效果图:

【Android】ListView与Button的共存问题解决