【安卓9】SimpleCursorAdapter、在列表中展示数据

SimpleCursorAdapter

SimpleCursorAdaper与SimpleAdapter类似，但数据来源是Cursor。

操作步骤：

在列表中展示数据

public MySQLiteOpenHelper(Context context) {
     super(context,"person.db",null,1);
}
public void onCreate(SQLiteDatabase db) {
    db.execSQL("create table if not exists person(" 
        +"_id integer primary key autoincrement,"
        +"name varchar(20)");
}
/**    查询方法
  * @return Cursor对象
  */
 public  Cursor  query(){
    SQLiteDatabase  db=getWritableDatabase();
    Cursor cursor=db.query("person", new String[]{"id _id ","name"}, null, null, null, null, null);
    return cursor;
 }
/**向数据库插入数据*/
    public void insert(String [] args){
        SQLiteDatabase db=this.getWritableDatabase();
        //该对象可操作键-值对数据
        ContentValues values=new ContentValues();
        values.put("name",args[0]);//存放数据
        //表名,强行插入null值得数据列的列名,记录数据
        db.insert("person",null,values);
    } 

Activity代码
public class Main extends Activity implements OnClickListener{
private  Button  addBtn;
private  Button  findBtn;
private  EditText nameEt;
private  EditText phoneEt;
private  ListView listView;
private  SimpleCursorAdapter  adapter;
private  MySQLiteOpenHelper  helper;
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        addBtn=(Button)findViewById(R.id.addBtn);
        findBtn=(Button)findViewById(R.id.findBtn);
        nameEt=(EditText)findViewById(R.id.nameEt);
        phoneEt=(EditText)findViewById(R.id.phoneEt);
        listView=(ListView)findViewById(R.id.lv);
        addBtn.setOnClickListener(this);
        findBtn.setOnClickListener(this);

        helper=new MySQLiteOpenHelper(this);
        Cursor  cursor=helper.query();
        adapter=new SimpleCursorAdapter(this,R.layout.list_item, 
        cursor,new String[]{"_id","name","phone"},
        new int[]{R.id.idTv,R.id.nameTv,R.id.phoneTv});
        listView.setAdapter(adapter);
    } 
public void onClick(View v) {
    MySQLiteOpenHelper  db=new MySQLiteOpenHelper(Main.this);
    switch(v.getId()){
    case R.id.addBtn:
        String  name=nameEt.getText().toString();
        String  phone=phoneEt.getText().toString();
        db.insert(new String[]{name,phone});
        Toast.makeText(this,"插入成功",3000).show();
    break;
   case R.id.findBtn:
           Cursor  cur=helper.query();
           adapter.changeCursor(cur);//更新游标适配器对象
           adapter.notifyDataSetChanged();//通知列表控件数据发生改变
    break;
}