java - 未知警告图标-Android Studio

这是我的simple_selector.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="false">
        <shape android:shape="rectangle">
            <solid android:color="@android:color/white" />
        </shape>
    </item>
    <item android:state_pressed="true">
        <shape android:shape="rectangle">
            <solid android:color="@android:color/darker_gray" />
        </shape>
    </item>
</selector>

出现警告图标背后的原因是什么，我在做什么错？

我正在使用 Android Studio v1.4.1 。

最佳答案

您应该有一个无状态项:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="false">
        <shape android:shape="rectangle">
            <solid android:color="@android:color/white" />
        </shape>
    </item>
    <item android:state_pressed="true">
        <shape android:shape="rectangle">
            <solid android:color="@android:color/darker_gray" />
        </shape>
    </item>

    <item>
        <shape android:shape="rectangle">
            <solid android:color="@android:color/darker_gray" />
        </shape>
    </item>
</selector>