• 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
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  • 原文地址:https://www.cnblogs.com/a354823200/p/3918756.html
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