Tokinonagare

Android Cursor 和 Query 问题处理 Android Studio 学习笔记

Andriod Andriod_studio Sqlite
02 Sep 2015
  • Demo: https://github.com/tokinonagare/AndroidStudioSQLiteSample

/app/src/main/java/com/tokinonagare/sqlitesample/MyDBHandler.java

Cursor

//Move to the first row in your results
cursor.moveToFirst();

while(!cursor.isAfterLast()) {
    if(cursor.getString(cursor.getColumnIndex("productname"))!= null) {
        sqLiteDatabaseString += cursor.getString(cursor.getColumnIndex("productname"));
        sqLiteDatabaseString += "\n";
    }
}

在这一段涉及Cursor取数据的代码中, 会出现点击addButton时, app卡死的情况, 内存似乎一直在益处, 感觉缺少终止代码.

研究了一下Cursor的方法后使用了如下代码替换, 解决了问题

while (cursor.moveToNext()){
    if(cursor.getString(cursor.getColumnIndex("productname"))!= null) {
        sqLiteDatabaseString += cursor.getString(cursor.getColumnIndex("productname"));
        sqLiteDatabaseString += "\n";
    }
}

cursor.close();

Query

  @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        String query = "CREATE TABLE " + TABLE_PRODUCTS + " ( " +
                COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                COLUMN_PRODUCTNAME + " TEXT " +
                ");";
        sqLiteDatabase.execSQL(query);
    }

AUTOINCREMENT, 这个逗号是为了避免出现 near的 Error 问题添加的.

转载请注明出处： Android cursor 和 query 问题处理 - Android Studio 学习笔记