问题

根据标题所述，我想从手机联系人中选择以给定字母开头的联系人列表。
例如：如果我只想选择以字母"A"开头的联系人，我尝试的当前代码如下：

val selecteContactsList: ArrayList<SelectedContactItem> = arrayListOf()
val cursor = context.contentResolver.query(
        ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
        arrayOf(
            ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME,
            ContactsContract.CommonDataKinds.Phone.NUMBER
        ),
        ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME + " LIKE ?",
        arrayOf("A%"),
        ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME
    )

while (cursor!!.moveToNext()) {
    val contactName =
        cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME))
    val contactNumber =
        cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER))
    val contactItem = SelectedContactItem(contactNumber, contactName)
    selecteContactsList.add(contactItem)
}
cursor.close()

但是这不会产生任何输出。总选择的联系人计数为0。
如有帮助，将不胜感激。提前谢谢。

val selecteContactsList: ArrayList<SelectedContactItem> = arrayListOf()
val cursor = context.contentResolver.query(
        ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
        arrayOf(
            ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME,
            ContactsContract.CommonDataKinds.Phone.NUMBER
        ),
        ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME + " = ?",
        arrayOf("A"),
        ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME
    )

    while (cursor!!.moveToNext()) {
        val contactName =
            cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME))
        val contactNumber =
            cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER))
        val contactItem = SelectedContactItem(contactNumber, contactName)
        selecteContactsList.add(contactItem)
    }
    cursor.close()

答案1

得分: 1

Phone.DISPLAY_NAME + " = ?",
arrayOf("A"),

意味着 '返回所有姓名为A的联系人'。我认为你想要询问 '返回所有姓名以字母A开头的联系人'，这是一个不同的查询。

要实现这个目标，你可以将代码更改为：

Phone.DISPLAY_NAME + " LIKE 'A%'"

如果你想要不区分大小写的查询（即包括以小写字母'a'开头的姓名），可以尝试：

Phone.DISPLAY_NAME + " LIKE 'A%' COLLATE NOCASE"

但是，如果你的目标是显示所有联系人的列表，并且有一个滚动侧边栏，用户可以触摸字母"C"并跳转到以该字母开头的联系人姓名，我不建议使用这样的查询，而是应该查询设备上的所有联系人，并将它们全部显示在一个可滚动的大列表中，然后当用户触摸字母按钮时，滚动到列表中的某个位置。

这样的用户体验会更出色。

<details>
<summary>英文:</summary>

the part:

Phone.DISPLAY_NAME + " = ?",
arrayOf("A"),

means 'return all contacts with name A'. 

I think you want to ask 'return all contacts with name starting with the letter A' which is a different query.

To do that you can change the code to:

Phone.DISPLAY_NAME + " LIKE 'A%'"

If you want a case insensitive query (i.e. include names that begin with small 'a'), try:

Phone.DISPLAY_NAME + " LIKE 'A%' COLLATE NOCASE"

However, if your goal is to show a list of all contacts, and have a scroller sidebar where the user can touch the letter "C" and jump to contact names beginning with that letter I would not suggest to have such queries, instead query for **all** contacts on the device, and show them all in one big scrollable list, and have those letters buttons scroll to a certain position in the list when touched.

The user experience would be far superior.


</details>