Android 访问 XML 中的 SDK 属性

Question

我正在尝试扩展 Android 的 simple_list_item_2，所以我复制了它的 XML，即:

<TwoLineListItem xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="?attr/listPreferredItemHeight"
    android:mode="twoLine"
    android:paddingStart="?attr/listPreferredItemPaddingStart"
    android:paddingEnd="?attr/listPreferredItemPaddingEnd">

    <TextView android:id="@id/text1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:textAppearance="?attr/textAppearanceListItem" />

    <TextView android:id="@id/text2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/text1"
        android:layout_alignStart="@id/text1"
        android:textAppearance="?attr/textAppearanceListItemSecondary" />

</TwoLineListItem>

问题是，在我的实现中，这条线

    android:textAppearance="?attr/textAppearanceListItemSecondary"/>

给出错误:

无法解析符号 ?attr/textAppearanceListItemSecondary

我试过类似的东西:

android:textAppearance="android:?attr/textAppearanceListItemSecondary"

和

android:textAppearance="@android?attr/textAppearanceListItemSecondary"但它不起作用

所以我的问题是，如何访问 Android SDK 资源中的布局可以访问的相同符号/属性？我是否需要将符号复制到我的应用程序目录，或者我可以简单地访问 simple_list_item_2 所做的那个？

此外，原始的 simple_list_item_2 位于 C:\Android\sdk\platforms\android-23\data\res\layout\ 而我对它的实现是位于 \app\src\main\res\layout 如果有帮助的话

Answer 1

android:textAppearance="?android:attr/textAppearanceListItemSecondary"

Documentation

您需要放置 ?在包名称之前，而不是之后:?[<package_name>:][<resource_type>/]<resource_name>

Referencing style attributes
A style attribute resource allows you to reference the value of an attribute in the currently-applied theme. Referencing a style attribute allows you to customize the look of UI elements by styling them to match standard variations supplied by the current theme, instead of supplying a hard-coded value. Referencing a style attribute essentially says, "use the style that is defined by this attribute, in the current theme."

To reference a style attribute, the name syntax is almost identical to the normal resource format, but instead of the at-symbol (@), use a question-mark (?), and the resource type portion is optional. For instance:

?[<package_name>:][<resource_type>/]<resource_name>