Android -- CursorAdapter
CursorAdapter
CursorAdapter继承于BaseAdapter,它是个虚类,它为cursor和ListView提供了连接的桥梁。
public abstract class CursorAdapter extends BaseAdapter
注意cursor的必须要有个命名为"_id"的列。比如Contacts._ID就为"_id"
必须实现以下函数：
abstract View newView(Context context, Cursor cursor, ViewGroup parent) abstract void bindView(View view, Context context, Cursor cursor)
newView该函数第一次回调用后，如果数据增加后也会再调用，但是重绘是不会调用的。
数据增加后,回调用该函数来生成与新增数据相对应的view。
bindView函数第一次回调用后，如果数据更新也会再调用，但重绘会再次调用的。
总的来说应该是在调用bindView如果发现view为空会先调用newView来生成view。
Code
public class MySqliteOpenhelper extends SQLiteOpenHelper { public MySqliteOpenhelper(Context context, int version) { super(context, "dianhuaben.db", null, version); } @Override public void onCreate(SQLiteDatabase db) {//注意：使用CursorAdapter时，创建表必须有以_id为列名的列 String sql = "CREATE TABLE dhb (_id INTEGER PRIMARY KEY AUTOINCREMENT,name VARCHAR(20),phone VARCHAR(20))"; db.execSQL(sql); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { } }
public void createCursorAdapter(Cursor cursor) { //游标适配器,构造方法，传入cursor mAdapter = new CursorAdapter(this, cursor) {//重写两个方法 @Override public View newView(Context context, Cursor cursor, ViewGroup parent) {//找到布局和控件 ViewHolder holder = new ViewHolder(); LayoutInflater inflater = getLayoutInflater(); View inflate = inflater.inflate(R.layout.listview_item, null); holder.item_tv_name = (TextView) inflate.findViewById(R.id.item_tv_name); holder.item_tv_phone = (TextView) inflate.findViewById(R.id.item_tv_phone); inflate.setTag(holder); return inflate;//返回的view传给bindView。 } @Override public void bindView(View view, Context context, Cursor cursor) { // 把数据设置到界面上 ViewHolder holder = (ViewHolder) view.getTag(); String name = cursor.getString(cursor.getColumnIndex("name")); String phone = cursor.getString(cursor.getColumnIndex("phone")); holder.item_tv_name.setText(name); holder.item_tv_phone.setText(phone); } }; };
SimpleCursorAdapter
简单提及一下
public void createSimpleCursorAdapter(Cursor cursor) {// SimpleCursorAdapter继承了CursorAdapter继承了BaseAdapter String[] from = {TABLE_NAME_NAME,TABLE_NAME_PHONE};//列名与控件id一一对应 int[] to = {R.id.item_tv_name,R.id.item_tv_phone}; //用的是SimpleCursorAdapter，用法和simpleAdapter相似 mAdapter = new SimpleCursorAdapter(MainActivity.this, R.layout.listview_item, cursor, from, to); }
使用SimpleCursorAdapter，时，创建表必须有以_id为列名的列
