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！
转: http://www.itivy.com/android/archive/2011/12/14/android-listview-checkbox-problem.html