Как удалить все записи из таблицы в sqlite с Android?

Question

Мое приложение имеет две кнопки: первая кнопка предназначена для удаления записи при вводе пользователем, а вторая кнопка предназначена для удаления всех записей.Но когда я хочу удалить данные, появляется сообщение
«Ваше приложение было принудительно остановлено».

Пожалуйста, проверьте мой код и дайте мне несколько советов.

public void deleteAll()
{
    //SQLiteDatabase db = this.getWritableDatabase();
   // db.delete(TABLE_NAME,null,null);
    //db.execSQL("delete * from"+ TABLE_NAME);
    db.execSQL("TRUNCATE table" + TABLE_NAME);
    db.close();
}

и

public void delete(String id)
{
    String[] args={id};
    getWritableDatabase().delete("texts", "_ID=?", args);
}

Но это показывает следующую ошибку Log cat.

03-07 15:57:07.143: ERROR/AndroidRuntime(287): Uncaught handler: thread main exiting due to uncaught exception
03-07 15:57:07.153: ERROR/AndroidRuntime(287): java.lang.NullPointerException
03-07 15:57:07.153: ERROR/AndroidRuntime(287):     at com.example.MySQLiteHelper.delete(MySQLiteHelper.java:163)
03-07 15:57:07.153: ERROR/AndroidRuntime(287):     at com.example.Settings$4.onClick(Settings.java:94)
-07 15:57:07.153: ERROR/AndroidRuntime(287):     at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:158)
03-07 15:57:07.153: ERROR/AndroidRuntime(287):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-07 15:57:07.153: ERROR/AndroidRuntime(287):     at android.os.Looper.loop(Looper.java:123)
03-07 15:57:07.153: ERROR/AndroidRuntime(287):     at android.app.ActivityThread.main(ActivityThread.java:4203)
03-07 15:57:07.153: ERROR/AndroidRuntime(287):     at java.lang.reflect.Method.invokeNative(Native Method)
03-07 15:57:07.153: ERROR/AndroidRuntime(287):     at java.lang.reflect.Method.invoke(Method.java:521)
03-07 15:57:07.153: ERROR/AndroidRuntime(287):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
03-07 15:57:07.153: ERROR/AndroidRuntime(287):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549)
03-07 15:57:07.153: ERROR/AndroidRuntime(287):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

//Delete all records of table
db.execSQL("DELETE FROM " + TABLE_NAME);

//Reset the auto_increment primary key if you needed
db.execSQL("UPDATE SQLITE_SEQUENCE SET SEQ=0 WHERE NAME=" + TABLE_NAME);

//For go back free space by shrinking sqlite file
db.execSQL("VACUUM");

Answer 2

    getContentResolver().delete(DB.TableName.CONTENT_URI, null, null);

Answer 3

этот метод удаляет все данные из базы данных

 public void deleteAll()
{
    SQLiteDatabase db = this.getWritableDatabase();
    db.execSQL("delete from "+ TABLE_NAME);
    db.close();
}

Answer 4

Может быть полезным.

public boolean deleteAllFood() {
            SQLiteDatabase db = dbHelper.getReadableDatabase();
            int affectedRows = db.delete(DBHelper.TABLE_NAME_FOOD, null, null);
            return affectedRows > 0;
        }



public class DBProgram {
    private static DBProgram INSTANCE;
    private Context context;
    private DBHelper dbHelper;

    private DBProgram(Context context) {
        // burda bu methodu kullanan activity ile eileştiriyoruz
        this.dbHelper = new DBHelper(context);
    }

    public static synchronized DBProgram getInstance(Context context) {
        if (INSTANCE == null) {
            INSTANCE = new DBProgram(context);
        }
        return INSTANCE;
    }

    //**********************************************
    public boolean updateById(ProgramModel program) {
        SQLiteDatabase database = dbHelper.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(DBHelper.COLUM_NAME_P, program.getProgName());
        contentValues.put(DBHelper.COLUM_DAY_P, program.getDay());
        contentValues.put(DBHelper.COLUMN_WEIGHT_P, program.getWeight());
        contentValues.put(DBHelper.COLUMN_SET_P, program.getSet());
        contentValues.put(DBHelper.COLUMN_REPETITION_P, program.getRepetition());
        int affectedRows = database.update(DBHelper.TABLE_NAME_PROGRAM, contentValues, "PROG_ID_P = ?", new String[]{String.valueOf(program.getId())});
        return affectedRows > 0;
    }
    //**********************************************


    //**********************************************
    // TODO
    public boolean deleteProgramById(int id) {
        SQLiteDatabase database = dbHelper.getReadableDatabase();
        int affectedRows = database.delete(DBHelper.TABLE_NAME_PROGRAM, DBHelper.COLUMN_ID_P + "= ?", new String[]{String.valueOf(id)});
        // return bize etkilenen sıra sayısınıını temsil eder
        return affectedRows > 0;
    }
    //**********************************************


    //***************************************************
    public boolean deleteProgramByName(String progName) {
        SQLiteDatabase database = dbHelper.getReadableDatabase();
        final String whereClause = DBHelper.COLUM_NAME_P + "=?";
        final String whereArgs[] = {progName};
        int affectedRows = database.delete(DBHelper.TABLE_NAME_PROGRAM, whereClause, whereArgs);
        return affectedRows > 0;
    }
    //***************************************************


    //************************************** get Meal
    // TODO  WEB Get All  Meals
    public List<ProgramModel> getAllProgram(String name) {
        List<ProgramModel> foodList = new ArrayList<>();
        ProgramModel food;
        SQLiteDatabase database = dbHelper.getReadableDatabase();
        final String kolonlar[] = {DBHelper.COLUMN_ID_P,
                DBHelper.COLUM_NAME_P,
                DBHelper.COLUM_DAY_P,
                DBHelper.COLUMN_WEIGHT_P,
                DBHelper.COLUMN_SET_P,
                DBHelper.COLUMN_REPETITION_P};

        final String whereClause = DBHelper.COLUM_DAY_P + "=?";
        final String whereArgs[] = {name};
        Cursor cursor = database.query(DBHelper.TABLE_NAME_PROGRAM, kolonlar, whereClause, whereArgs, null, null, null);
        while (cursor.moveToNext()) {

            food = new ProgramModel();
            food.setId(cursor.getInt(cursor.getColumnIndex(DBHelper.COLUMN_ID_P)));
            food.setProgName(cursor.getString(cursor.getColumnIndex(DBHelper.COLUM_NAME_P)));
            food.setDay(cursor.getString(cursor.getColumnIndex(DBHelper.COLUM_DAY_P)));
            food.setWeight(cursor.getInt(cursor.getColumnIndex(DBHelper.COLUMN_WEIGHT_P)));
            food.setSet(cursor.getInt(cursor.getColumnIndex(DBHelper.COLUMN_SET_P)));
            food.setRepetition(cursor.getInt(cursor.getColumnIndex(DBHelper.COLUMN_REPETITION_P)));
            foodList.add(food);
        }
        database.close();
        cursor.close();
        return foodList;
    }
    //**************************************


    //**************************************insert FOOD
    //TODO LOCAL insert Foods
    public boolean insertProgram(ProgramModel favorite) {
        boolean result = false;
        ContentValues contentValues = new ContentValues();
        contentValues.put(DBHelper.COLUM_NAME_P, favorite.getProgName());
        contentValues.put(DBHelper.COLUM_DAY_P, favorite.getDay());
        contentValues.put(DBHelper.COLUMN_WEIGHT_P, favorite.getWeight());
        contentValues.put(DBHelper.COLUMN_SET_P, favorite.getSet());
        contentValues.put(DBHelper.COLUMN_REPETITION_P, favorite.getRepetition());
        SQLiteDatabase database = dbHelper.getWritableDatabase();
        long id = database.insert(DBHelper.TABLE_NAME_PROGRAM, null, contentValues);
        if (id != 1) {
            result = true;
        }
        database.close();

        return result;
    }
    //***************************************************

    // *******************************  SQLITE HELPER CLASS ******************
    private class DBHelper extends SQLiteOpenHelper {
        private final Context context;
        private static final String DATABASE_NAME = "PROGRAM_INFO";
        private static final String TABLE_NAME_PROGRAM = "PROGRAM";
        private static final int DATABASE_VERSION = 2;

        // FOOD
        private static final String COLUMN_ID_P = "PROG_ID_P";
        private static final String COLUM_NAME_P = "PROG_NAME_P";
        private static final String COLUM_DAY_P = "PROG_DAY_P";
        private static final String COLUMN_WEIGHT_P = "PROG_WEIGHT_P";
        private static final String COLUMN_SET_P = "PROG_SET_P";
        private static final String COLUMN_REPETITION_P = "PROG_REPETITION_P";

        private final String CREATE_TABLE_PROGRAM = "CREATE TABLE " + TABLE_NAME_PROGRAM +
                " (" + COLUMN_ID_P + " INTEGER PRIMARY KEY AUTOINCREMENT, "
                + COLUM_NAME_P + " TEXT, "
                + COLUM_DAY_P + " TEXT, "
                + COLUMN_WEIGHT_P + " INTEGER, "
                + COLUMN_SET_P + " INTEGER, "
                + COLUMN_REPETITION_P + " INTEGER)";

        private static final String DROP_TABLE_PROGRAM = "DROP TABLE IF EXIST " + TABLE_NAME_PROGRAM;

        public DBHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
            this.context = context;
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL(CREATE_TABLE_PROGRAM);

            Util.showMessage(context, "Database Created");
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            db.execSQL(DROP_TABLE_PROGRAM);
            Util.showMessage(context, "Database Upgrated");
            onCreate(db);
        }

        @Override
        public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            super.onDowngrade(db, oldVersion, newVersion);
        }
    }


}