Listview和checkbox多選

   在Android某些開發需求當中,有時候須要在listveiw中加入checkbox實現單選,多選操做。表面上看上去只是改變checkbox那麼簡單,然而實際開發中,實現起來並非那麼駕輕就熟。尤爲當listview比較多(好比屏幕最多隻能顯示10個item,但總共有12個item,也就是說listview的item數大於屏幕可以顯示的item數)滑動屏幕的時候,因爲適配器中getview()會重複使用被移除屏幕的item,因此會形成checkbox選擇狀態不正常的現象。本身在開發中碰到這樣的問題非常苦惱,查了下資料,發現網上不多沒有針對這類批量操做並無一個完整的例子。搜了不少篇帖子才完美的實現這一經常使用的操做。因此在這裏把這個Demo貼出來,供你們參考,但願能對你們有所幫助。html

      主界面的佈局main.xml    這個就很少說什麼java

 

<LinearLayout
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
         >
    <TextView 
        android:layout_width="fill_parent"
        android:layout_height="100dip"
        android:text="原創:Simtice                                  QQ:512375320"
        android:layout_marginLeft="10dip"
        />
    </LinearLayout><?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="全選"
	        android:gravity="center"
	        />
	    <Button 
	        android:id="@+id/inverseselect"
	        android:layout_width="80dip"	
	        android:layout_height="50dip"
	        android:layout_marginLeft="118dip"
	        android:text="反選"
	        android:gravity="center"
	        />
	    <Button 
	        android:id="@+id/cancel"
	        android:layout_width="80dip"	
	        android:layout_height="50dip"
	        android:layout_marginLeft="213dip"
	        android:text="取消已選"
	        android:gravity="center"
	        />
	</RelativeLayout>
           <LinearLayout
                android:orientation="vertical"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
               >
             <TextView 
                 android:layout_width="fill_parent"
                 android:layout_height="100dip"
                 android:text="原創:Simtice                                  QQ:512375320"
                 android:layout_marginLeft="10dip"
               />
         </LinearLayout>
 </LinearLayout>

 

ListView每一個item的佈局,listviewitem.xml:android

這裏須要注意的是,因爲checkbox的點擊事件優先級比listview的高,因此要添加android:focusable="false"屬性,使得checkbox初始的時候沒有獲取焦點。ide

另外這裏是點擊ListView的item控制checkbox的狀態改變,也就是讓item接收clik事件,因此須要加上android:focusableInTouchMode="false"這一屬性。佈局

<?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類this

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

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


爲listview自定義適配器,該類爲主Activity類MainActivity.java的內部類spa

 

class MyAdapter extends BaseAdapter {
		@Override
		public int getCount() {
			return list.size();
		}

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

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

		@Override
		public View getView(int position, View view, ViewGroup arg2) {
			System.out.println("getView " + position + " " + view);
			ViewHolder holder;
			if (view == null || (holder = (ViewHolder) view.getTag()) == null) {
				view = View.inflate(MainActivity.this, R.layout.listviewitem,
						null);
				holder = new ViewHolder();
				holder.tv = (TextView) view.findViewById(R.id.item_tv);
				holder.cb = (CheckBox) view.findViewById(R.id.item_cb);
				view.setTag(holder);
			}
			Item item = getItem(position);
			holder.tv.setText(item.name);
			holder.cb.setChecked(item.status);
			return view;
		}

 

最後,最重要的就是MainActivity.java中一些事件響應的處理3d

public class MainActivity extends Activity implements OnClickListener {
	TextView tv = null;
	ListView lv = null;
	String name[] = { "G1", "G2", "G3", "G4", "G5", "G6", "G7", "G8", "G9",
			"G10", "G11", "G12", "G13", "G14" };

	private List<Item> list;
	private List<String> data;
	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);

		this.findViewById(R.id.selectall).setOnClickListener(this);
		this.findViewById(R.id.inverseselect).setOnClickListener(this);
		this.findViewById(R.id.cancel).setOnClickListener(this);

		lv.setOnItemClickListener(new OnItemClickListener() {
			@Override
			public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
					long arg3) {
				Item item = list.get(arg2);
				item.status = !item.status;// 取反
				initAdapter();
			}
		});

		init();

	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.selectall:
			int size1 = list.size();
			for (int i = 0; i < size1; i++) {
				list.get(i).status = true;
			}
			break;
		case R.id.inverseselect:
			int size2 = list.size();
			for (int i = 0; i < size2; i++) {
				Item item = list.get(i);
				item.status = !item.status;// 取反
			}
			break;
		case R.id.cancel:
			int size3 = list.size();
			for (int i = 0; i < size3; i++) {
				list.get(i).status = false;
			}
			break;
		}
		initAdapter();
	}

	// 數據初始化
	private void init() {
		if (list == null)
			list = new ArrayList<Item>();
		else
			list.clear();
		if (data == null)
			data = new ArrayList<String>();
		for (String s : name) {
			list.add(new Item(s, false));
		}
		initAdapter();
	}

	// 刷新適配器
	public void initAdapter() {
		if (adapter == null) {
			adapter = new MyAdapter();
			lv.setAdapter(adapter);
		} else {
			adapter.notifyDataSetChanged();
		}

		int size = list.size();
		data.clear();
		for (int i = 0; i < size; i++) {
			if (list.get(i).status)
				 /*這裏能夠處理checkbox爲true時的事件*/  
                               data.add(name[i]);  
            else                  
               /*爲false時的事件*/  
				data.remove(name[i]);
		}
		tv.setText("已選中 " + data.size() + " 項");
	}

	// 爲listview自定義適配器內部類
	class MyAdapter extends BaseAdapter {
		...
	}

	class Item {
		public String name;
		public boolean status = false;

		public Item(String name, boolean b) {
			this.name = name;
			this.status = b;
		}
	}

我選擇了G二、G三、G11三項,如今屏幕滑動到底部,看以看到狀態保存的很好,TextView顯示已選中3項。全選、反選、取消已選功能正常,多選操做完美解決!code

 

源碼:http://www.eoeandroid.com/thread-152037-1-1.htmlxml

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