build.gradle

buildscript {...}

allprojects {...}

// This block encapsulates custom properties and makes them available to all
// modules in the project.
ext {
    // The following are only a few examples of the types of properties you can define.
    compileSdkVersion = 25
    buildToolsVersion = "25.0.0"
    // You can also create properties to specify versions for dependencies.
    // Having consistent versions between modules can avoid conflicts with behavior.
    supportLibraryVersion = "25.1.1"
    ...
}
...