Android在listview添加checkbox實現單選多選操作問題

在 android 某些開發需求當中，有時候需要在listveiw中加入checkbox實現單選，多選操作。表面上看上去只是改變checkbox那麼簡單，然而實際開發中，實現起來並不是那麼得心應手。尤其當listview比較多(比如屏幕最多隻能顯示10個item，但總共有12個item，也就是說listview的item數大於屏幕能夠顯示的item數)滑動屏幕的時候，由於適配器中getview()會重複使用被移除屏幕的item，所以會造成checkbox選擇狀態不正常的現象。自己在開發中碰到這樣的問題很是苦惱，查了下資料，發現網上很少沒有針對這類批量操作並沒有一個完整的例子。搜了很多篇帖子才完美的實現這一常用的操作。所以在這裏把這個Demo貼出來，供大家參考，希望能對大家有所幫助。

主界面的佈局main.xml 這個就不多說什麼

<?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>

ListView每個item的佈局,listviewitem.xml：

這裏需要注意的是，由於checkbox的點擊事件優先級比listview的高，所以要添加android:focusable="false"屬性，使得checkbox初始的時候沒有獲取焦點。

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，所以需要加上android:focusableInTouchMode="false"這一屬性。

<?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類

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

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; // 記錄每個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 設置所有checkbox都爲未選擇 
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; 
} 
 
} 

最後，最重要的就是MainActivity.java中一些事件響應的處理

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(); 
 
//全選 
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();//注意這一句必須加上，否則checkbox無法正常更新狀態 
tv.setText("已選中"+listStr.size()+"項"); 
} 
}); 
 
//反選 
 
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("已選中"+listStr.size()+"項"); 
}
 
}); 
//取消已選 
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("已選中"+listStr.size()+"項"); 
 
} 
 
}); 
} 
 
// 顯示帶有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();// 在每次獲取點擊的item時改變checkbox的狀態 
MyAdapter.isSelected.put(position, holder.cb.isChecked()); // 同時修改map的值保存狀態 
if (holder.cb.isChecked() == true) { 
listStr.add(name[position]); 
} else { 
listStr.remove(name[position]); 
} 
tv.setText("已選中"+listStr.size()+"項"); 
} 
 
}); 
} 
} 
 
//爲listview自定義適配器內部類 
 
public static class MyAdapter extends BaseAdapter { 
... 
} 
}

選擇了G2、G3、G11三項，現在屏幕滑動到底部，看以看到狀態保存的很好，TextView顯示已選中3項。全選、反選、取消全選功能正常，多選操作完美解決！