手把手教你实现GridView中Checkbox全选

简介: 手把手教你实现GridView中Checkbox全选

image.png

全选效果图

这节讲得相对比较基础的东西,高手请忽略。

首先新建一个GridviewAdapter继承BaseAdapter

public class GridviewAdapter extends BaseAdapter{  
    private ArrayList<Person> list;  
    private static HashMap<Integer,Boolean> isSelected;  
    private Context context;  
    private LayoutInflater inflater = null;  
    public GridviewAdapter(ArrayList<Person> list, Context context) {  
        this.context = context;  
        this.list = list;  
        inflater = LayoutInflater.from(context);  
        isSelected = new HashMap<Integer, Boolean>();  
        initDate();  
    }  
    private void initDate(){  
        for(int i=0; i<list.size();i++) {  
            getIsSelected().put(i,false);  
        }  
    }  
    @Override  
    public int getCount() {  
        return list.size();  
    }  
    @Override  
    public Object getItem(int position) {  
        return list.get(position);  
    }  
    @Override  
    public long getItemId(int position) {  
        return position;  
    }  
    @Override  
    public View getView(final int position, View convertView, ViewGroup parent) {  
        ViewHolder holder = null;  
            if (convertView == null) {  
            holder = new ViewHolder();  
            convertView = inflater.inflate(R.layout.gridviewitem, null);  
            holder.name = (TextView) convertView.findViewById(R.id.item_name);  
            holder.ID = (TextView) convertView.findViewById(R.id.item_ID);  
            holder.cb = (CheckBox) convertView.findViewById(R.id.item_cb);  
            convertView.setTag(holder);  
        } else {  
            holder = (ViewHolder) convertView.getTag();  
            }  
        holder.ID.setText(list.get(position).getId());  
        holder.name.setText(list.get(position).getName());  
        holder.cb.setChecked(getIsSelected().get(position));  
        return convertView;  
    }  
    static class ViewHolder{    
        CheckBox cb;    
        TextView name;    
        TextView ID;    
    }  
    public static HashMap<Integer,Boolean> getIsSelected() {  
        return isSelected;  
    }  
    public static void setIsSelected(HashMap<Integer,Boolean> isSelected) {  
        GridviewAdapter.isSelected = isSelected;  
    }  
}  

下面我们新建一个Activity来看看效果:

public class MainActivity extends Activity implements OnClickListener {  
    private GridView gd;  
    private GridviewAdapter mAdapter;  
    private ArrayList<Person> persons;  
    private Button bt_selectall;  
    private Button bt_cancel;  
    private Button bt_deselectall;  
    private Button bt_sumit;  
    private int checkNum; // 记录选中的条目数量  
    private TextView tv_show;// 用于显示选中的条目数量  
    List<String> selectID = new ArrayList<String>(); //选中的ID  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
        initView();  
        initData();  
        gd.setOnItemClickListener(new OnItemClickListener() {  
            @Override  
            public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,  
                    long arg3) {  
                ViewHolder holder = (ViewHolder) arg1.getTag();  
                holder.cb.toggle();  
                GridviewAdapter.getIsSelected().put(arg2, holder.cb.isChecked());  
                if (holder.cb.isChecked() == true) {  
                    checkNum++;  
                } else {  
                    checkNum--;  
                }  
                tv_show.setText("已选中" + checkNum + "项");  
            }  
        });  
    }  
    /** 
     * 初始化数据 
     */  
    private void initData() {  
        Person mPerson;  
        for (int i = 1; i <= 40; i++) {  
            mPerson = new Person();  
            mPerson.setName("aikaifa" + i);  
            // mPerson.setId(Character.valueOf((char)(i+65))+" ");  
            mPerson.setId(i + "");  
            persons.add(mPerson);  
        }  
        mAdapter = new GridviewAdapter(persons, this);  
        gd.setAdapter(mAdapter);  
    }  
    /** 
     * 刷新 
     */  
    private void dataChanged() {  
        mAdapter.notifyDataSetChanged();  
        tv_show.setText("已选中" + checkNum + "项");  
    }  
    /** 
     * 初始化控件 
     */  
    private void initView() {  
        gd = (GridView) findViewById(R.id.gd);  
        bt_selectall = (Button) findViewById(R.id.bt_selectall);  
        bt_cancel = (Button) findViewById(R.id.bt_cancelselectall);  
        bt_deselectall = (Button) findViewById(R.id.bt_deselectall);  
        bt_sumit = (Button) findViewById(R.id.bt_submit);  
        tv_show = (TextView) findViewById(R.id.tv);  
        persons = new ArrayList<Person>();  
        bt_selectall.setOnClickListener(this);  
        bt_cancel.setOnClickListener(this);  
        bt_deselectall.setOnClickListener(this);  
        bt_sumit.setOnClickListener(this);  
    }  
    /** 
     * 全选 
     */  
    private void selectAll() {  
        for (int i = 0; i < persons.size(); i++) {  
            GridviewAdapter.getIsSelected().put(i, true);  
        }  
        // 数量设为list的长度  
        checkNum = persons.size();  
        dataChanged();  
    }  
    /** 
     * 全不选 
     */  
    private void cancelselectall() {  
        // 遍历list的长度,将已选的按钮设为未选  
        for (int i = 0; i < persons.size(); i++) {  
            if (GridviewAdapter.getIsSelected().get(i)) {  
                GridviewAdapter.getIsSelected().put(i, false);  
                checkNum--;// 数量减1  
            }  
        }  
        dataChanged();  
    }  
    /** 
     * 反选 
     */  
    private void deselectall() {  
        // 遍历list的长度,将已选的设为未选,未选的设为已选  
        for (int i = 0; i < persons.size(); i++) {  
            if (GridviewAdapter.getIsSelected().get(i)) {  
                GridviewAdapter.getIsSelected().put(i, false);  
                checkNum--;  
            } else {  
                GridviewAdapter.getIsSelected().put(i, true);  
                checkNum++;  
            }  
        }  
        dataChanged();  
    }  
    /** 
     * 提交 
     */  
    private void submit() {  
        selectID.clear();  
        for (int i = 0; i < mAdapter.getIsSelected().size(); i++) {  
            if (mAdapter.getIsSelected().get(i)) {  
                selectID.add(persons.get(i).getId());  
            }  
        }  
        if (selectID.size() == 0) {  
            AlertDialog.Builder builder1 = new AlertDialog.Builder(  
                    MainActivity.this);  
            builder1.setMessage("没有选中任何记录");  
            builder1.show();  
        } else {  
            StringBuilder sb = new StringBuilder();  
            for (int i = 0; i < selectID.size(); i++) {  
                sb.append("ID=" + selectID.get(i) + "  ");  
            }  
            AlertDialog.Builder builder2 = new AlertDialog.Builder(MainActivity.this);  
            builder2.setMessage(sb.toString());  
            builder2.show();  
        }  
    }  
    @Override  
    public void onClick(View v) {  
        switch (v.getId()) {  
        case R.id.bt_selectall:  
            selectAll();  
            break;  
        case R.id.bt_cancelselectall:  
            cancelselectall();  
            break;  
        case R.id.bt_deselectall:  
            deselectall();  
            break;  
        case R.id.bt_submit:  
            submit();  
            break;  
        }  
    }  
}  

对应的activity_main.xml布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    xmlns:tools="http://schemas.android.com/tools"  
    android:id="@+id/LinearLayout1"  
    android:layout_width="match_parent"  
    android:layout_height="match_parent"  
    android:orientation="vertical"  
>  
 <LinearLayout  
        android:layout_width="match_parent"  
        android:layout_height="wrap_content"  
        android:orientation="horizontal"  
        >  
        <Button  
            android:id="@+id/bt_selectall"  
            android:layout_width="wrap_content"  
            android:layout_height="wrap_content"  
            android:text="全选" />  
        <Button  
            android:id="@+id/bt_cancelselectall"  
            android:layout_width="wrap_content"  
            android:layout_height="wrap_content"  
            android:text="全不选" />  
        <Button  
            android:id="@+id/bt_deselectall"  
            android:layout_width="wrap_content"  
            android:layout_height="wrap_content"  
            android:text="反选" />  
        <Button  
            android:id="@+id/bt_submit"  
            android:layout_width="wrap_content"  
            android:layout_height="wrap_content"  
            android:text="提交" />  
    </LinearLayout>  
    <TextView  
        android:id="@+id/tv"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:text="TextView" />  
    <GridView  
        android:id="@+id/gd"  
        android:layout_width="fill_parent"  
        android:layout_height="fill_parent"  
        android:numColumns="2" />  
</LinearLayout>  

其中有个实体类

public class Person {  
    private String name;  
    private String Id;  
    public String getName() {  
        return name;  
    }  
    public void setName(String name) {  
        this.name = name;  
    }  
    public String getId() {  
        return Id;  
    }  
    public void setId(String id) {  
        Id = id;  
    }     
}  

gridviewitem.xml布局

<?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="fill_parent"  
    android:orientation="horizontal" >  
    <TextView  
        android:id="@+id/item_ID"  
        android:layout_width="0dp"  
        android:layout_height="wrap_content"  
        android:layout_weight="1"  
        android:gravity="center_vertical"  
        android:visibility="gone" />  
    <TextView  
        android:id="@+id/item_name"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:gravity="center_vertical" />  
    <CheckBox  
        android:id="@+id/item_cb"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:clickable="false"  
        android:focusable="false"  
        android:focusableInTouchMode="false"  
        android:gravity="center_vertical" />  
</LinearLayout>  


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