As you know, interstitials are a great way to monetize your app while still providing a great user experience, with natural "commercial breaks" in your user flow. However, interstitials can take a while to load, and we know that this can make it tricky to implement since you must explicitly call loadAd() before calling show().

A common mistake is to call interstitial.show() in the onAdLoaded() callback. This makes the show() call not dependent on the app state, but on the asynchronous loading. Since the developer doesn't control when the onAdLoaded() callback happens, this provides a terrible user experience; the ad will show as soon as it's finished loading, which could be in the middle of another user interaction. This can result in policy violations due to accidental clicks.

Instead, we recommend loading the ad earlier in the lifecycle of the application, then polling interstitial.isLoaded() to see if the ad is ready to be shown. If it isn't ready, we recommend moving to the next state in the application.

We provide an example of proper interstitial loading in our sample "Impossible" game. When the game begins, we call loadAd() on the interstitial. When the user loses and clicks the button to try the game again, we check to see if the ad is loaded with isLoaded(). If it is, then we show an ad before starting the new round. Otherwise, we show a toast message that the ad isn't loaded and begin a new round.

This example focuses on the Android experience, but the same ideas apply to iOS. We hope our new interstitial example can help you create the best user experience as you integrate the Mobile Ads SDK into your apps. Check out this video for more on interstitial best practices. And as you're adding interstitials to your app, hit us up with technical questions on our developer forum!

 - Amy Quispe, Mobile Ads Developer Relations

Like any Android library, the Google Play services SDK impacts the final size of applications that include it. Good developers care about the size of their apps, so today we’d like to show you two ways that you can leverage the Android plugin for gradle to reduce the APK size of applications that include Google Play services.

1. Split JAR Architecture

   Beginning with Google Play services 6.5, additional maven artifacts have been added to the Google Repository that contain single domains of functionality. This means that you can include just those portions of Google Play services that your app uses. For example, here’s how to configure gradle to incorporate the JAR that contains functionality relating to ads:

   dependencies {
       compile 'com.google.android.gms:play-services-ads:6.5.+'
   }
   

   That line instructs gradle to include everything Mobile Ads developers need, with the exception of the IMA SDK JAR needed for IMA applications.

   Please note that if you currently initialize Mobile Ads SDK banner ads via XML layout files, you should continue including the full Google Play services artifact. See this blog post for more information.

2. Shrink Resources

   The Android gradle plugin supports the ability to automatically exclude unused resources during the build process via the shrinkResources gradle property. To take advantage of this in your release builds, just add “shrinkResources true” to your build.gradle file’s release configuration:

   android {
       buildTypes {
           release {
               minifyEnabled true
               shrinkResources true
           }
       }
   }
   

   Note that the shrinkResources property requires that minifyEnabled be set to true as well, though that’s already a good practice for release builds.

Both of these techniques are quick to implement, so consider giving them a try. In testing, the use of shrinkResources and the new, split JAR maven artifacts reduced the APK size of our Interstitial Example by 1.2MB -- almost 50%!

If you have questions about these techniques and how to put them to work in your applications, visit us on the Mobile Ads SDK forum or the IMA SDK forum.

 - Andrew Brogdon, Mobile Ads Developer Relations