ListView 和 其它能觸發點擊事件的widget無法一起正常工作的原因是加入其它widget后,ListView的itemclick事件將無法觸發,被其它widget的click事件屏蔽。
- 首先,說明一下,ListView中每一行包括以下三項:
一個ImageView, 一個TextView,一個ImageButton,依次排開。
以下是layout的內容,分為兩部分:
- 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因為繼承了ListActivity,所以ListView 的id設置為"@id/android:list"是必須的
注意:
在<RelativeLayout>中
android:descendantFocusability="blocksDescendants"
和<ImageButton>中
android:focusable="false"
這兩項的設置很關鍵,如果不設置,將導致ListView的ItemClick事件將無法觸發,該事件被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" /> <!-- 把按鈕背景設置為透明: android:background="#00000000" 把按鈕背景設置為半透明: 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,為了能處理ImageButton的click事件,我繼承了BaseAdapter類,並重新實現了getView()接口,在其中加入了Button的clicklistener,詳見lvButtonAdapter類的實現。接下來,我們看看繼承ListActivity的實現
public class lvWithButtonExt extends ListActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // 關聯Layout中的ListView ListView vncListView = (ListView)findViewById(android.R.id.list); // 生成動態數組,加入數據 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);//圖像資源的ID map.put("ItemWinName", "Window ID "+i); map.put("ItemCloseWin",android.R.drawable.ic_menu_close_clear_cancel); remoteWindowItem.add(map); } // 生成適配器的Item和動態數組對應的元素 lvButtonAdapter listItemAdapter = new lvButtonAdapter( this, remoteWindowItem,//數據源 R.layout.lvitem,//ListItem的XML實現 //動態數組與ImageItem對應的子項 new String[] {"ItemImage","ItemWinName", "ItemCloseWin"}, //ImageItem的XML文件里面的一個ImageView,兩個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); } }
為了響應按鈕的點擊事件,首先要記錄按鈕的位置,然后為按鈕設置clicklistener。接下來,我們看看lvButtonAdapter的實現
在重新實現的getView()接口中,我使用了lvButtonListener監聽類,在構造函數中,記錄行號,以便在OnClick接口中能准確的定位按鈕所在的位置,進而對相應的行進行處理。
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); } } }
點擊右邊的按鈕該行將被刪除以下是運行效果圖:
