Getting Error “Gradle DSL method not found: ‘compile()'” when Syncing Build.Gradle

In almost all cases, your dependencies should be put into the individual module’s build.gradle files rather than at the top most level build.gradle file. In your case, that means the dependency should be added to the app module’s build.gradle file:

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile "com.android.support:support-v4:18.0.+"
}

And you should remove the entire allprojects part of the top level build.gradle.