ContentProvider 的索引值如何理解？

Question

private String getQueryData() {
        StringBuilder sb = new StringBuilder();
        ContentResolver cr = getContentResolver();
        Cursor cursor = cr.query(ContactsContract.Contacts.CONTENT_URI, columns, null, null, null);
        // To get the index value of id

        int IdIndex = cursor.getColumnIndex(columns[0]);
        int nameIndex = cursor.getColumnIndex(columns[1]);
        for (cursor.moveToFirst();!cursor.isAfterLast();cursor.moveToNext()) {
            int id = cursor.getInt(IdIndex);
            String displayName = cursor.getString(nameIndex);
            sb.append(id + ":" + displayName + "\n");
        }

怎么理解这求索引值这几个，转来转去的.....有点乱

可以按照多维数组来理解吗？index就是相当于它的定位坐标？？

Answer 1

ColumnIndex是列序号索引，比如

id	username	password

这么一个表结构
那么id的index就是0
username为1
password为2