完美解决Android在listview添加checkbox实现单选多选操作问题

在Android某些开发需求当中，有时候需要在listveiw中加入checkbox实现单选，多选操作。表面上看上去只是改变checkbox那么简单，然而实际开发中，实现起来并不是那么得心应手。尤其当listview比较多(比如屏幕最多只能显示10个item，但总共有12个item，也就是说listview的item数大于屏幕能够显示的item数)滑动屏幕的时候，由于适配器中getview()会重复使用被移除屏幕的item，所以会造成checkbox选择状态不正常的现象。自己在开发中碰到这样的问题很是苦恼，查了下资料，发现网上很少没有针对这类批量操作并没有一个完整的例子。搜了很多篇帖子才完美的实现这一常用的操作。所以在这里把这个Demo贴出来，供大家参考，希望能对大家有所帮助。

主界面的布局main.xml 这个就不多说什么

<?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="wrap_content"
    android:orientation="vertical" >
	<LinearLayout
	    android:orientation="vertical"
	    android:layout_width="fill_parent"
	    android:layout_height="wrap_content"
	     >
	    <TextView 
	        android:id="@+id/tv"
	        android:layout_width="fill_parent"
	        android:layout_height="50dip"
	        android:textColor="#FCFCFC"
	        android:textSize="11pt"
	        android:gravity="center_vertical"
	        android:layout_marginLeft="10dip"
	        /> 
	<ListView
        android:id="@+id/lv"
        android:layout_width="fill_parent"
        android:layout_height="381dip"
        android:cacheColorHint ="#00000000"
         ></ListView>
	</LinearLayout>
	<RelativeLayout 
	    android:layout_width="fill_parent"
	    android:layout_height="53dip"
	    android:orientation="horizontal"
	    >
	    <Button 
	        android:id="@+id/selectall"
	        android:layout_width="80dip"	
	        android:layout_height="50dip"
	        android:layout_marginLeft="20dip"
	        android:text="全选"
	        android:gravity="center"
	        />
	    <Button 
	        android:id="@+id/inverseselect"
	        android:layout_width="80dip"	
	        android:layout_height="50dip"
	        android:layout_marginLeft="118dip"
	        android:text="反选"
	        android:gravity="center"
	        />
	    <Button 
	        android:id="@+id/cancel"
	        android:layout_width="80dip"	
	        android:layout_height="50dip"
	        android:layout_marginLeft="213dip"
	        android:text="取消已选"
	        android:gravity="center"
	        />
	</RelativeLayout>
</LinearLayout>

ListView每个item的布局,listviewitem.xml：

这里需要注意的是，由于checkbox的点击事件优先级比listview的高，所以要添加android:focusable="false"属性，使得checkbox初始的时候没有获取焦点。

另外这里是点击ListView的item控制checkbox的状态改变，也就是让item接收clik事件，所以需要加上android:focusableInTouchMode="false"这一属性。

<?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="55dip"
    android:orientation="horizontal"
    android:layout_marginTop="20dip"
    > 
	<TextView 
	    android:id="@+id/item_tv"
	    android:layout_width="267dip"
        android:layout_height="40dip"
	    android:textSize="10pt"
	    android:gravity="center_vertical"
	    android:layout_marginLeft="10dip"
	    />
    <CheckBox 
        android:id="@+id/item_cb"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:focusable="false"    
        android:focusableInTouchMode="false"    
        android:clickable="false"  
        android:layout_toRightOf="@id/item_tv"   
        android:layout_alignParentTop="true"
        android:layout_marginRight="5dip"
       
        />
</RelativeLayout >

ViewHolder类

package simtice.test.listview.viewholder;
import android.widget.CheckBox;
import android.widget.TextView;

public class ViewHolder {
	public TextView tv = null;
	public CheckBox cb = null;
}

为listview自定义适配器，该类为主Activity类MainActivity.java的内部类

public static class MyAdapter extends BaseAdapter {
		public static HashMap<Integer, Boolean> isSelected;
		private Context context = null;
		private LayoutInflater inflater = null;
		private List<HashMap<String, Object>> list = null;
		private String keyString[] = null;
		private String itemString = null; // 记录每个item中textview的值
		private int idValue[] = null;// id值

		public MyAdapter(Context context, List<HashMap<String, Object>> list,
				int resource, String[] from, int[] to) {
			this.context = context;
			this.list = list;
			keyString = new String[from.length];
			idValue = new int[to.length];
			System.arraycopy(from, 0, keyString, 0, from.length);
			System.arraycopy(to, 0, idValue, 0, to.length);
			inflater = LayoutInflater.from(context);
			init();
		}

		// 初始化 设置所有checkbox都为未选择
		public void init() {
			isSelected = new HashMap<Integer, Boolean>();
			for (int i = 0; i < list.size(); i++) {
				isSelected.put(i, false);
			}
		}

		@Override
		public int getCount() {
			return list.size();
		}

		@Override
		public Object getItem(int arg0) {
			return list.get(arg0);
		}

		@Override
		public long getItemId(int arg0) {
			return 0;
		}

		@Override
		public View getView(int position, View view, ViewGroup arg2) {
			ViewHolder holder = null;
			if (holder == null) {
				holder = new ViewHolder();
				if (view == null) {
					view = inflater.inflate(R.layout.listviewitem, null);
				}
				holder.tv = (TextView) view.findViewById(R.id.item_tv);
				holder.cb = (CheckBox) view.findViewById(R.id.item_cb);
				view.setTag(holder);
			} else {
				holder = (ViewHolder) view.getTag();
			}
			HashMap<String, Object> map = list.get(position);
			if (map != null) {
				itemString = (String) map.get(keyString[0]);
				holder.tv.setText(itemString);
			}
			holder.cb.setChecked(isSelected.get(position));
			return view;
		}

	}

最后，最重要的就是MainActivity.java中一些事件响应的处理

public class MainActivity extends Activity {
	TextView tv = null;
	ListView lv = null;
	Button btn_selectAll = null;
	Button btn_inverseSelect = null;
	Button btn_calcel = null;
	String name[] = { "G1", "G2", "G3", "G4", "G5", "G6", "G7", "G8", "G9",
			"G10", "G11", "G12", "G13", "G14" };
	
	ArrayList<String> listStr = null;
	private List<HashMap<String, Object>> list = null;
	private MyAdapter adapter;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		tv = (TextView) this.findViewById(R.id.tv);
		lv = (ListView) this.findViewById(R.id.lv);
		btn_selectAll = (Button) this.findViewById(R.id.selectall);
		btn_inverseSelect = (Button) this.findViewById(R.id.inverseselect);
		btn_calcel = (Button) this.findViewById(R.id.cancel);
		showCheckBoxListView();
		
		//全选
		btn_selectAll.setOnClickListener(new OnClickListener(){
			@Override
			public void onClick(View arg0) {
				listStr = new ArrayList<String>();
				for(int i=0;i<list.size();i++){
					MyAdapter.isSelected.put(i,true);
					listStr.add(name[i]);
				}
				adapter.notifyDataSetChanged();//注意这一句必须加上，否则checkbox无法正常更新状态
				tv.setText("已选中"+listStr.size()+"项");
			}
		});
		
		//反选
		btn_inverseSelect.setOnClickListener(new OnClickListener(){
			@Override
			public void onClick(View v) {
				for(int i=0;i<list.size();i++){
					if(MyAdapter.isSelected.get(i)==false){
						MyAdapter.isSelected.put(i, true);
						listStr.add(name[i]);
					}
					else{
						MyAdapter.isSelected.put(i, false);
						listStr.remove(name[i]);
					}
				}
				adapter.notifyDataSetChanged();
				tv.setText("已选中"+listStr.size()+"项");
			}
			
		});
		
		//取消已选
		btn_calcel.setOnClickListener(new OnClickListener(){
			@Override
			public void onClick(View v) {
				for(int i=0;i<list.size();i++){
					if(MyAdapter.isSelected.get(i)==true){
						MyAdapter.isSelected.put(i, false);
						listStr.remove(name[i]);
					}
				}
				adapter.notifyDataSetChanged();
				tv.setText("已选中"+listStr.size()+"项");
			}
			
		});
	}

	// 显示带有checkbox的listview
	public void showCheckBoxListView() {
		list = new ArrayList<HashMap<String, Object>>();
		for (int i = 0; i < name.length; i++) {
			HashMap<String, Object> map = new HashMap<String, Object>();
			map.put("item_tv", name[i]);
			map.put("item_cb", false);
			list.add(map);

			adapter = new MyAdapter(this, list, R.layout.listviewitem,
					new String[] { "item_tv", "item_cb" }, new int[] {
							R.id.item_tv, R.id.item_cb });
			lv.setAdapter(adapter);
			listStr = new ArrayList<String>();
			lv.setOnItemClickListener(new OnItemClickListener() {

				@Override
				public void onItemClick(AdapterView<?> arg0, View view,
						int position, long arg3) {
					ViewHolder holder = (ViewHolder) view.getTag();
					holder.cb.toggle();// 在每次获取点击的item时改变checkbox的状态
					MyAdapter.isSelected.put(position, holder.cb.isChecked()); // 同时修改map的值保存状态
					if (holder.cb.isChecked() == true) {
						listStr.add(name[position]);
					} else {
						listStr.remove(name[position]);
					}
					tv.setText("已选中"+listStr.size()+"项");
				}

			});
		}
	}

	//为listview自定义适配器内部类
	public static class MyAdapter extends BaseAdapter {
		...
	}
}

好了，来看运行结果

我选择了G2、G3、G11三项，现在屏幕滑动到底部，看以看到状态保存的很好，TextView显示已选中3项。全选、反选、取消全选功能正常，多选操作完美解决！