AAPT: error: resource android:attr/fontVariationSettings not found
摘要：
Android Studio中提示的錯誤Log:
/Users/lijiangping/.gradle/caches/transforms-1/files-1.1/appcompat-v7-27.1.1.aar/c85964a61f36e1b83cfed8dc0b27cbc1/res/va...
Android Studio中提示的錯誤Log:
/Users/lijiangping/.gradle/caches/transforms-1/files-1.1/appcompat-v7-27.1.1.aar/c85964a61f36e1b83cfed8dc0b27cbc1/res/values/values.xml:251:5-69: AAPT: error: resource android:attr/fontVariationSettings not found. /Users/lijiangping/.gradle/caches/transforms-1/files-1.1/appcompat-v7-27.1.1.aar/c85964a61f36e1b83cfed8dc0b27cbc1/res/values/values.xml:251:5-69: AAPT: error: resource android:attr/ttcIndex not found.
引起的原因：專案中引入了多個aar，每個aar對應了不同的appcompat-v7版本，為了不引起錯誤，我們會設定force某個版本，但是問題就在這邊，需要設定最高版本保證其他aar中引用的高資源內容不會因為我們設定低版本而出錯。
/Users/lijiangping/MyProject/PP/framework/build.gradle: Error: All com.android.support libraries must use the exact same version specification (mixing versions can lead to runtime crashes). Found versions 28.0.0, 27.1.1, 25.2.0 . Examples include com.android.support:collections:28.0.0 and com.android.support:animated-vector-drawable:27.1.1 [GradleCompatible]
因此我們需要將我們的appcompat-v7版本force為這些aar中最高的版本：28.0.0
在build.gradle中加入：
configurations.all {
resolutionStrategy.eachDependency { DependencyResolveDetails details ->
def requested = details.requested
if (requested.group == 'com.android.support') {
if (!requested.name.startsWith("multidex")) {
details.useVersion '28.0.0'
}
}
}
}