• 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

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  • 原文地址:https://www.cnblogs.com/andgoo/p/2690349.html
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