java - 内容提供商 ListView 限制

Question

我想限制我的应用中显示的联系人数量。目前，它正在查询我的 Contactscontract.Contacts DB 并返回每个具有电话号码的主要显示名称。有没有一种简单的方法可以将其减少到数字量(例如仅显示 5 个联系人)或某些指定的 ID？

这是我到目前为止所拥有的:

    public Loader<Cursor> onCreateLoader(int id, Bundle args) {

    // load from the "Contacts table"
    Uri contentUri = ContactsContract.Contacts.CONTENT_URI;

    // no sub-selection, no sort order, simply every row
    // projection says we want just the _id and the name column
    return new CursorLoader(getActivity(),
            contentUri,
            PROJECTION,
            ContactsContract.Contacts.HAS_PHONE_NUMBER + " =?", // This is selection string, were looking for records that HAS_PHONE_NUMER is 1
            new String[]{"1"}, // 1 means that contact has a phone number
            ContactsContract.Contacts._COUNT,
            new String[] {"5"},
            null);
}

每当我尝试在返回部分添加新参数时，Android Studio 都会立即变为红色，表示无法解析构造函数。这是因为 CursorLoader 没有定义为接收更多参数吗？

我之前在代码中将其定义为:

mAdapter = new SimpleCursorAdapter(context, layout, c, FROM, TO, flags);

干杯，夏姆

Answer 1

要实现查询结果的限制，请在您的查询中添加(字符串连接)“LIMIT 5”:

...
ContactsContract.Contacts.HAS_PHONE_NUMBER + "=? LIMIT 5" //This is selection string, were looking for records that HAS_PHONE_NUMER is 1 AND 
// the result set is limited to 5 rows
new String[]{"1"},
null);
...