解决appcompat冲突问题 All com.android.support libraries must use the exact same version specification (mix

All com.android.support libraries must use the exact same version specification (mixing versions can lead to runtime crashes). Found versions 26.1.0, 25.0.0. Examples include com.android.support:animated-vector-drawable:26.1.0 and com.android.support:support-v13:25.0.0 less... (Ctrl+F1) 
There are some combinations of libraries, or tools and libraries, that are incompatible, or can lead to bugs. One such incompatibility is compiling with a version of the Android support libraries that is not the latest version (or in particular, a version lower than your targetSdkVersion.)

app下的build.gradle加入以下代码，根据自己项目同步

configurations.all {
    resolutionStrategy.eachDependency { DependencyResolveDetails details ->
        def requested = details.requested
        if (requested.group == 'com.android.') {
            if (!requested.name.startsWith("multidex")) {
                details.useVersion '26.1.0'
            }
        }
    }
}