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http://www.eoeandroid.com/thread-198019-1-1.html
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http://www.eoeandroid.com/thread-198033-1-1.html
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>
<?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 {
...
}
}
效果图:
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!