数据库操作简单示例

package mutou.test; import android.database.sqlite.*; import android.content.Context; import android.database.sqlite.SQLiteDatabase.CursorFactory; public class MySQLiteHelper extends SQLiteOpenHelper { public MySQLiteHelper(Context context, String name, CursorFactory factory, int version) { super(context, name, factory, version); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL("create table if not exists hero_info(" + "id integer primary key," + "name varchar," + "level integer)"); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // TODO Auto-generated method stub } }

package mutou.test; import android.app.Activity; import android.content.ContentValues; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.os.Bundle; import android.widget.TextView; public class Sample43Activity extends Activity { MySQLiteHelper myHelper; TextView tv; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); tv = (TextView)this.findViewById(R.id.tv); myHelper = new MySQLiteHelper(this, "my.db", null, 1); insertAndUpdateData(myHelper); String result = queryData(myHelper); tv.setText("名字\t登记\n" + result); } public void insertAndUpdateData(MySQLiteHelper myHelper) { SQLiteDatabase db = myHelper.getWritableDatabase(); db.execSQL("insert into hero_info(name, level) values('mutou', 1)"); ContentValues values = new ContentValues(); values.put("name", "music"); values.put("level", 2); db.insert("hero_info", "id", values); values.clear(); values.put("name", "musicvs"); values.put("level", 3); db.update("hero_info", values, "level = 2", null); } public String queryData(MySQLiteHelper myHelper) { String result = ""; SQLiteDatabase db = myHelper.getReadableDatabase(); Cursor cursor = db.query("hero_info", null, null, null, null, null, "id asc"); int nameIndex = cursor.getColumnIndex("name"); int levelIndex = cursor.getColumnIndex("level"); for(cursor.moveToFirst(); cursor.isAfterLast() != true; cursor.moveToNext()) { result += cursor.getString(nameIndex) + " "; result += cursor.getString(levelIndex) + " \n"; } cursor.close(); db.close(); return result; } @Override protected void onDestroy() { SQLiteDatabase db = myHelper.getWritableDatabase(); /* 获取数据库对象 */ //db.delete("hero_info", "1", null); super.onDestroy(); } }