Implementation principle and code of adding checkbox to listview by Android

The main interface CheckBoxinListViewActivity. java code is as follows:: Copy codeThe Code is as follows: public class CheckBoxinListViewActivity extends Activity {
/** Called when the activity is first created .*/
Private MyAdapter adapter;
Private ListView listview;
Private Button checkAll;
Private Button noCheckAll;
@ Override
Public void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. main );
Listview = (ListView) findViewById (R. id. listview );
CheckAll = (Button) findViewById (R. id. button1 );
NoCheckAll = (Button) findViewById (R. id. button2 );
Adapter = new MyAdapter ();
Listview. setAdapter (adapter );
CheckAll. setOnClickListener (new OnClickListener (){
@ Override
Public void onClick (View v ){
Adapter. checkAll ();
}
});
NoCheckAll. setOnClickListener (new OnClickListener (){
@ Override
Public void onClick (View v ){
Adapter. noCheckAll ();
}
});
}
Private class MyAdapter extends BaseAdapter {
Private ArrayList <Message> list = new ArrayList <Message> ();
Public MyAdapter (){
For (int I = 1; I <= 100; I ++ ){
List. add (new Message ("item _" + I ));
}
}
Public void checkAll (){
For (Message msg: list ){
Msg. isCheck = true;
}
NotifyDataSetChanged ();
}
Public void noCheckAll (){
For (Message msg: list ){
Msg. isCheck = false;
}
NotifyDataSetChanged ();
}
@ Override
Public int getCount (){
Return list. size ();
}
@ Override
Public Object getItem (int position ){
Return null;
}
@ Override
Public long getItemId (int position ){
Return 0;
}
@ Override
Public View getView (int position, View convertView, ViewGroup parent ){
ViewHolder viewHolder;
If (convertView = null ){
LayoutInflater inflater = LayoutInflater. from (CheckBoxinListViewActivity. this );
ConvertView = inflater. inflate (R. layout. listview_item, null );
ViewHolder = new ViewHolder ();
ViewHolder. checkBox = (CheckBox) convertView. findViewById (R. id. checkBox1 );
ConvertView. setTag (viewHolder );
} Else {
ViewHolder = (ViewHolder) convertView. getTag ();
}
Final Message msg = list. get (position );
ViewHolder. checkBox. setText (msg. str );
ViewHolder. checkBox. setChecked (msg. isCheck );
// Note that onCheckedChangListener is not set here, so it is worth thinking about.
ViewHolder. checkBox. setOnClickListener (new OnClickListener (){
@ Override
Public void onClick (View v ){
If (msg. isCheck ){
Msg. isCheck = false;
} Else {
Msg. isCheck = true;
}
}
});
Return convertView;
}
}
Private class ViewHolder {
CheckBox checkBox;
}
}

The Message. java applicable to the adapter is as follows:Copy codeThe Code is as follows: public class Message {
Public boolean isCheck;
Public String str;
Public Message (String str ){
This. str = str;
}
}

The main. xml Code is as follows:Copy codeThe Code is as follows: <? Xml version = "1.0" encoding = "UTF-8"?>
<LinearLayout xmlns: android = "http://schemas.android.com/apk/res/android"
Android: orientation = "vertical" android: layout_width = "fill_parent"
Android: layout_height = "fill_parent">
<LinearLayout
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content">
<Button android: text = "select all" android: id = "@ + id/button1"
Android: layout_width = "wrap_content" android: layout_height = "wrap_content"> </Button>
<Button android: text = "undo" android: id = "@ + id/button2"
Android: layout_width = "wrap_content" android: layout_height = "wrap_content"> </Button>
</LinearLayout>
<ListView android: id = "@ + id/listview" android: layout_height = "fill_parent"
Android: layout_width = "fill_parent"/>
</LinearLayout>

The listview_item.xml code is as follows:Copy codeThe Code is as follows: <? 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: descendantFocusability = "blocksDescendants"
>
<LinearLayout
Android: layout_width = "fill_parent"
Android: layout_height = "wrap_content"
Android: gravity = "center">
<CheckBox
Android: text = "CheckBox"
Android: id = "@ + id/checkBox1"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"/>
</LinearLayout>
</LinearLayout>

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