sqlite 数据库封装类html
DatabaseUtil.java(封装的类)java
packagecom.jack.androidbase.tools;importandroid.content.ContentValues;importandroid.content.Context;importandroid.database.Cursor;importandroid.database.SQLException;importandroid.database.sqlite.SQLiteDatabase;importandroid.database.sqlite.SQLiteOpenHelper;importandroid.util.Log;/*** sqlite 数据库操做类*/
public classDatabaseUtil {private static final String TAG = "DatabaseUtil";/*** Database Name*/
private static final String DATABASE_NAME = "student_data";/*** Database Version*/
private static final int DATABASE_VERSION = 1;/*** Table Name*/
private static final String DATABASE_TABLE = "tb_student";/*** Table columns*/
public static final String KEY_NAME = "name";public static final String KEY_GRADE = "grade";public static final String KEY_ROWID = "_id";/*** Database creation sql statement*/
private static final String CREATE_TABLE =
"create table " + DATABASE_TABLE + " (" + KEY_ROWID + " integer primary key autoincrement, "
+ KEY_NAME + " text not null, " + KEY_GRADE + " text not null);";/*** Context*/
private finalContext mCtx;privateDatabaseHelper mDbHelper;privateSQLiteDatabase mDb;/*** Inner private class. Database Helper class for creating and updating database.*/
private static class DatabaseHelper extendsSQLiteOpenHelper {
DatabaseHelper(Context context) {super(context, DATABASE_NAME, null, DATABASE_VERSION);
}/*** onCreate method is called for the 1st time when database doesn't exists.*/@Overridepublic voidonCreate(SQLiteDatabase db) {
Log.i(TAG,"Creating DataBase: " +CREATE_TABLE);
db.execSQL(CREATE_TABLE);
}/*** onUpgrade method is called when database version changes.*/@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, intnewVersion) {
Log.w(TAG,"Upgrading database from version " + oldVersion + " to "
+newVersion);
}
}/*** Constructor - takes the context to allow the database to be
* opened/created
*
*@paramctx the Context within which to work*/
publicDatabaseUtil(Context ctx) {this.mCtx =ctx;
}/*** This method is used for creating/opening connection
*
*@returninstance of DatabaseUtil
*@throwsSQLException*/
public DatabaseUtil open() throwsSQLException {
mDbHelper= newDatabaseHelper(mCtx);
mDb=mDbHelper.getWritableDatabase();return this;
}/*** This method is used for closing the connection.*/
public voidclose() {
mDbHelper.close();
}/*** This method is used to create/insert new record record.
*
*@paramname
*@paramgrade
*@returnlong*/
public longinsert(String name, String grade) {
ContentValues initialValues= newContentValues();
initialValues.put(KEY_NAME, name);
initialValues.put(KEY_GRADE, grade);return mDb.insert(DATABASE_TABLE, null, initialValues);
}/*** This method will delete record.
*
*@paramrowId
*@returnboolean*/
public boolean delete(longrowId) {return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}/*** This method will deleteAll record.
*
*@return
*/
public booleandeleteAll() {return mDb.delete(DATABASE_TABLE, " 1 ", null) > 0;
}/*** This method will return Cursor holding all the records.
*
*@returnCursor*/
publicCursor fetchAll() {return mDb.query(DATABASE_TABLE, newString[]{KEY_ROWID, KEY_NAME,
KEY_GRADE},null, null, null, null, null);
}/*** This method will return Cursor holding the specific record.
*
*@paramid
*@returnCursor
*@throwsSQLException*/
public Cursor fetch(long id) throwsSQLException {
Cursor mCursor=mDb.query(true, DATABASE_TABLE, newString[]{KEY_ROWID,
KEY_NAME, KEY_GRADE}, KEY_ROWID+ "=" + id, null,null, null, null, null);if (mCursor != null) {
mCursor.moveToFirst();
}returnmCursor;
}/*** This method will update record.
*
*@paramid
*@paramname
*@paramstandard
*@returnboolean*/
public boolean update(intid, String name, String standard) {
ContentValues args= newContentValues();
args.put(KEY_NAME, name);
args.put(KEY_GRADE, standard);return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + id, null) > 0;
}
}
使用详解：android
DatabaseUtil dbUtil = new DatabaseUtil(this);
dbUtil.open();
switch (v.getId()) {
case R.id.other_btn_sqlite_list: //查询
Cursor cursor = dbUtil.fetchAll();
if (cursor != null) {
while (cursor.moveToNext()) {
Log.i("Student", "ID:" + cursor.getInt(0) + ",Student Name: " + cursor.getString(1) +
",Grade: " + cursor.getString(2));
}
}
break;
case R.id.other_btn_sqlite_add:
dbUtil.insert("Prashant Thakkar", "100");
Log.i("Student", "add over");
break;
case R.id.other_btn_sqlite_update:
dbUtil.update(1, "aa", "bb");
Log.i("Student", "update over");
break;
case R.id.other_btn_sqlite_del:
dbUtil.delete(2);
Log.i("Student", "delete over");
break;
case R.id.other_btn_sqlite_del_all:
dbUtil.deleteAll();
Log.i("Student", "delete all over");
break;
}
dbUtil.close();sql
参考网址：数据库
https://www.cnblogs.com/sowhat4999/p/4439856.htmlide
https://www.cnblogs.com/ProMonkey/p/5765616.html (有添加单例模式)fetch
本博客地址： wukong1688this
转载请著名出处！谢谢~~spa
