Question

image 我想得到整行我使用此代码来获取我想要的数据，但它在temp_address1给我空指针异常这里是代码

如上所述，我希望得到整行匹配的电话号码。我怎么能得到这个结果？电话号码是这里的主要关键公共类SqliteHelpers扩展了SQLiteOpenHelper {

public static final String DATABASE_NAME = "NotesDatabase.db";
public static final int DATABASE_VERSION = 1;
public static final String TABLE_NAME = "notesDb";
public static final String NUMBER = "PhoneNumber";
public static final String NOTES = "Note";
public static final String PICTURE = "Picture";

public static final String TABLE_CREATE =
        "CREATE TABLE " +
                TABLE_NAME + "(" +
                NUMBER + " TEXT PRIMAY KEY , " +
                NOTES + " TEXT UNIQUE , " +
                PICTURE + " TEXT  " + " ) ";

public SqliteHelpers(Context context) {
    super(context, DATABASE_NAME, null, 1);
    getReadableDatabase();
    getWritableDatabase();
}

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL(TABLE_CREATE);
    Log.i("DBHelpers", "table created");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS" + TABLE_NAME);

}

和第二堂课是

公共类DataBaseHelpers {

private SQLiteDatabase mDbHelper;
private SqliteHelpers mSqliteHelper;
private Cursor mCursor;

public DataBaseHelpers(Context context) {
    mSqliteHelper = new SqliteHelpers(context);
}


void createNewEntry(String column, String value) {
    ContentValues values = new ContentValues();
    values.put(column, value);
    mDbHelper.insert(SqliteHelpers.TABLE_NAME, null, values);
    Log.i("Sqlite", "create entry");
}

void deleteItem(String column, String value) {
    mDbHelper.delete(SqliteHelpers.TABLE_NAME, column + " = ?", new String[]{value});
    Log.i("sqlite", "Entry deleted");
}

void closeDatabase() {
    mSqliteHelper.close();
    Log.i("sqlite", "close database");
}

void retrieveDate(String value) {

    String query = "SELECT * FROM notesDb WHERE PhoneNumber ="
            + value;
    mCursor = mDbHelper.rawQuery(query, null);
    if (mCursor.moveToFirst()) {
        do {
            String temp_address = mCursor.getString(mCursor.getColumnIndex(SqliteHelpers.NUMBER));
            String temp_address1 = mCursor.getString(mCursor.getColumnIndex(SqliteHelpers.NOTES));
            System.out.println(temp_address);
            System.out.println(temp_address1);

        } while (cursor.moveToNext());
    }
    mDbHelper.close();

}

Answer 1

你可以像下面的代码

那样做

public void rec(int _id){
  String query = "SELECT * FROM notesDb WHERE PhoneNumber ="
        + _id;
  SQLiteDatabase db = this.getWritableDatabase();
  Cursor cursor = db.rawQuery(query, null);
  if (cursor.moveToFirst()) {
    do {
        String temp_address = c.getString(0);

        String temp_address1 = c.getString(1);
        System.out.println(temp_address);
        System.out.println(temp_address1);

    } while (cursor.moveToNext());
}
db.close();
}

根据Sqlite中的Row选择数据

1 个答案: