CheckedTextView的Android checkMarkGravity属性(api 21)

Question

来自plattform源的select_dialog_singlechoice_material.xml布局使用android:checkMarkGravity ="start"属性:

<?xml version="1.0" encoding="utf-8"?>
<!--
 Copyright (C) 2014 The Android Open Source Project
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
      http://www.apache.org/licenses/LICENSE-2.0
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-->

<CheckedTextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@android:id/text1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="?android:attr/listPreferredItemHeightSmall"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textColor="?android:attr/textColorAlertDialogListItem"
android:gravity="center_vertical"
android:paddingStart="@dimen/alert_dialog_padding_material"
android:paddingEnd="@dimen/alert_dialog_padding_material"
android:checkMark="?android:attr/listChoiceIndicatorSingle"
android:checkMarkGravity="start"
android:ellipsize="marquee" />

但是我无法在项目中使用此属性,因为我收到以下错误:

错误:(15)在'android'包中找不到属性'checkMarkGravity'的资源标识符

是否可以以某种方式使用此属性？我正在为api 21编译,所以这应该没关系:

minSdkVersion 21
targetSdkVersion 21

Answer 1

我不知道这个属性是否正确，但官方文档中不存在\xc2\xb4t： http://developer.android.com/intl/es/reference/android/widget/CheckedTextView.html

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无论如何，该值出现在该文件的同一个项目中（第 2052 行）：\n https://github.com/android/platform_frameworks_base/blob/59701b9ba5c453e327bc0e6873a9f6ff87a10391/core/res/res/values/symbols.xml

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