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 { ... } }
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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