Question

我需要使用其唯一的_ID将光标加载到多个联系人。我可以获得所有联系人的列表，但是我遇到了CursorLoader的SELECTION参数问题。

到目前为止我所拥有的是：

private static final String SELECTION = Contacts._ID + " IN (?)";

public Loader<Cursor> onCreateLoader(int arg0, Bundle arg1) {

    Uri contentUri = Contacts.CONTENT_URI;

    String selection[] = new String[1]; 
    selection[0] = "8,50";

    return new CursorLoader(getActivity(), contentUri, PROJECTION,
            SELECTION, selection, null);
}

这返回没有行。如果我将选择数组更改为

selection[0] = "8"

然后它正确地返回_ID为8的联系人。

任何人对如何使用_ID检索多个联系人有什么想法？

提前致谢。

Answer 1

您需要使用id in (?,?)来选择2个项目，如果您选择了多个IDs，则必须将(?,?,..)与选择项目的数量相同。然后在IDs数组中列出selectionArgs[]列表，如下所示：

String[] projection =...
String selectionArgs[] = {"8","50"};

String selection = Contacts._ID + " in (";
for (int i = 0; i < selectionArgs.length; i++) {
selection += "?, ";
}
selection = selection.substring(0, selection.length() - 2) + ")";
return new CursorLoader(getActivity(), contentUri, projection,
            selection, selectionArgs, null);

Answer 2

我做了一个快速测试，发现这个sql语句对我有用：

String select = "((" + Contacts.DISPLAY_NAME + " NOTNULL) AND ("
                + Contacts.HAS_PHONE_NUMBER + "=1) AND ("
                + Contacts.DISPLAY_NAME + " != '' ) AND ("
                + Contacts._ID + " in (369, 330)))";

此处的代码段：

    public Loader<Cursor> onCreateLoader(int id, Bundle args) {
        // This is called when a new Loader needs to be created.  This
        // sample only has one Loader, so we don't care about the ID.
        // First, pick the base URI to use depending on whether we are
        // currently filtering.
        Uri baseUri;
        if (mCurFilter != null) {
            baseUri = Uri.withAppendedPath(Contacts.CONTENT_FILTER_URI,
                    Uri.encode(mCurFilter));
        } else {
            baseUri = Contacts.CONTENT_URI;
        }

        // Now create and return a CursorLoader that will take care of
        // creating a Cursor for the data being displayed.
        String select = "((" + Contacts.DISPLAY_NAME + " NOTNULL) AND ("
                + Contacts.HAS_PHONE_NUMBER + "=1) AND ("
                + Contacts.DISPLAY_NAME + " != '' ) AND (" 
                + Contacts._ID + " in (369, 330)))";
        return new CursorLoader(getActivity(), baseUri,
                CONTACTS_SUMMARY_PROJECTION, select, null,
                Contacts.DISPLAY_NAME + " COLLATE LOCALIZED ASC");
    }

对于您正在使用的其他选项，我也对其进行了测试。如果您确实想使用selectParameters，请以这种方式使用它：

        // Now create and return a CursorLoader that will take care of
        // creating a Cursor for the data being displayed.
        String select = "((" + Contacts.DISPLAY_NAME + " NOTNULL) AND ("
                + Contacts.HAS_PHONE_NUMBER + "=1) AND ("
                + Contacts.DISPLAY_NAME + " != '' ) AND (" 
                + Contacts._ID + " in (?,?)))";

        String selectionParams[] = new String[2]; 
        selectionParams[0] = "369";
        selectionParams[1] = "330";

        return new CursorLoader(getActivity(), baseUri,
                CONTACTS_SUMMARY_PROJECTION, select, selectionParams,
                Contacts.DISPLAY_NAME + " COLLATE LOCALIZED ASC");

希望这对你有帮助。

带有多个Contacts._ID的Android CursorLoader

2 个答案: