Android Studio 引入uiautomator 问题：Manifest merger failed : uses-sdk:minSdkVersion 15 cannot be smaller

Manifest merger failed : uses-sdk:minSdkVersion 15 cannot be smaller than version 18 declared in library [io.apptik.widget:multislider-uiautomator:1.3] C:\Users\Frank\.gradle\caches\transforms-1\files-1.1\multislider-uiautomator-1.3.aar\0ff63d1f85db697572b346fa268d09e0\AndroidManifest.xml as the library might be using APIs not available in 15
    Suggestion: use a compatible library with a minSdk of at most 15,
        or increase this project's minSdk version to at least 18,
        or use tools:overrideLibrary="io.apptik.widget.mslider.uiautomator" to force usage (may lead to runtime failures)

问题分析：
1. 建立项目是minsdkversion:15 是15，在Android studio 3.1.2 版本中引入uiautomator 最低是18，否则会造成项目运行编译错误。

解决方法：
build.grable(Module:app)

defaultConfig{
    minSdkVersion 15  修改为：18
}