SQLiteOpenHelper的使用范例

创建数据库

public class DBHelper extends SQLiteOpenHelper {private static final String DB_NAME = "coll.db";private static final String TBL_NAME = "CollTbl";private static final String CREATE_TBL = " create table "+ " CollTbl(_id integer primary key autoincrement,name text,url text, desc text) ";private SQLiteDatabase db;DBHelper(Context c) {super(c, DB_NAME, null, 2);}@Overridepublic void onCreate(SQLiteDatabase db) {this.db = db;db.execSQL(CREATE_TBL);}public void insert(ContentValues values) {SQLiteDatabase db = getWritableDatabase();db.insert(TBL_NAME, null, values);db.close();}public Cursor query() {SQLiteDatabase db = getWritableDatabase();Cursor c = db.query(TBL_NAME, null, null, null, null, null, null);return c;}public void del(int id) {if (db == null)db = getWritableDatabase();db.delete(TBL_NAME, "_id=?", new String[] { String.valueOf(id) });}public void close() {if (db != null)db.close();}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}}

对数据库进行增加数据

String name = et1.getText().toString();String url = et2.getText().toString();String desc = et3.getText().toString();ContentValues values = new ContentValues();values.put("name", name);values.put("url", url);values.put("desc", desc);DBHelper helper = new DBHelper(getApplicationContext());helper.insert(values);Intent intent = new Intent(AddActivity.this,QueryActivity.class);startActivity(intent);

对数据库进行查询和删除

public class QueryActivity extends ListActivity {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);this.setTitle("浏览收藏信息");final DBHelper helpter = new DBHelper(this);Cursor c = helpter.query();String[] from = { "_id", "name", "url", "desc" };int[] to = { R.id.text0, R.id.text1, R.id.text2, R.id.text3 };SimpleCursorAdapter adapter = new SimpleCursorAdapter(this,R.layout.row, c, from, to);ListView listView = getListView();listView.setAdapter(adapter);final AlertDialog.Builder builder = new AlertDialog.Builder(this);listView.setOnItemClickListener(new OnItemClickListener() {@Overridepublic void onItemClick(AdapterView<?> arg0, View arg1, int arg2,long arg3) {final long temp = arg3;builder.setMessage("真的要删除该记录吗？").setPositiveButton("是",new DialogInterface.OnClickListener() {public void onClick(DialogInterface dialog,int which) {helpter.del((int)temp);Cursor c = helpter.query();String[] from = { "_id", "name", "url", "desc" };int[] to = { R.id.text0, R.id.text1, R.id.text2, R.id.text3 };SimpleCursorAdapter adapter = new SimpleCursorAdapter(getApplicationContext(),R.layout.row, c, from, to);ListView listView = getListView();listView.setAdapter(adapter);}}).setNegativeButton("否",new DialogInterface.OnClickListener() {public void onClick(DialogInterface dialog,int which) {}});AlertDialog ad = builder.create();ad.show();}});helpter.close();}}