【安卓9】SimpleCursorAdapter、在列表中展示数据

 1 public MySQLiteOpenHelper(Context context) {
 2      super(context,"person.db",null,1);
 3 }
 4 public void onCreate(SQLiteDatabase db) {
 5     db.execSQL("create table if not exists person(" 
 6         +"_id integer primary key autoincrement,"
 7         +"name varchar(20)");
 8 }
 9 /**    查询方法
10   * @return Cursor对象
11   */
12  public  Cursor  query(){
13     SQLiteDatabase  db=getWritableDatabase();
14     Cursor cursor=db.query("person", new String[]{"id _id ","name"}, null, null, null, null, null);
15     return cursor;
16  }
17 /**向数据库插入数据*/
18     public void insert(String [] args){
19         SQLiteDatabase db=this.getWritableDatabase();
20         //该对象可操作键-值对数据
21         ContentValues values=new ContentValues();
22         values.put("name",args[0]);//存放数据
23         //表名,强行插入null值得数据列的列名,记录数据
24         db.insert("person",null,values);
25     } 

 1 Activity代码
 2 public class Main extends Activity implements OnClickListener{
 3 private  Button  addBtn;
 4 private  Button  findBtn;
 5 private  EditText nameEt;
 6 private  EditText phoneEt;
 7 private  ListView listView;
 8 private  SimpleCursorAdapter  adapter;
 9 private  MySQLiteOpenHelper  helper;
10     public void onCreate(Bundle savedInstanceState) {
11         super.onCreate(savedInstanceState);
12         setContentView(R.layout.main);
13         addBtn=(Button)findViewById(R.id.addBtn);
14         findBtn=(Button)findViewById(R.id.findBtn);
15         nameEt=(EditText)findViewById(R.id.nameEt);
16         phoneEt=(EditText)findViewById(R.id.phoneEt);
17         listView=(ListView)findViewById(R.id.lv);
18         addBtn.setOnClickListener(this);
19         findBtn.setOnClickListener(this);
20 
21         helper=new MySQLiteOpenHelper(this);
22         Cursor  cursor=helper.query();
23         adapter=new SimpleCursorAdapter(this,R.layout.list_item, 
24         cursor,new String[]{"_id","name","phone"},
25         new int[]{R.id.idTv,R.id.nameTv,R.id.phoneTv});
26         listView.setAdapter(adapter);
27     } 
28 public void onClick(View v) {
29     MySQLiteOpenHelper  db=new MySQLiteOpenHelper(Main.this);
30     switch(v.getId()){
31     case R.id.addBtn:
32         String  name=nameEt.getText().toString();
33         String  phone=phoneEt.getText().toString();
34         db.insert(new String[]{name,phone});
35         Toast.makeText(this,"插入成功",3000).show();
36     break;
37    case R.id.findBtn:
38            Cursor  cur=helper.query();
39            adapter.changeCursor(cur);//更新游标适配器对象
40            adapter.notifyDataSetChanged();//通知列表控件数据发生改变
41     break;
42 }