Question

为什么不在这个代码工作 SQLiteOpenHelper

Answer 1

请尝试通过这种方式

private static final int DB_VERSION = 2; UPDATE HERE

public int getContactsCount() {
String countQuery = "SELECT * FROM " + TABLE_SOURCES;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
int count = cursor.getCount();
cursor.close();

// return count
return count;
}

private Database db = new Database(this);
Toast.makeText(this, String.valueOf(db.getContactsCount()),
Toast.LENGTH_LONG).show();