App bundle (.abb) size is bigger than APK (.apk), should not be the opposite?

Question

The code is practically the same, I just added one class, is it because when the Bundle is installed in a device just a part of it is going to go to that device and its size is going to be lower?

Answer 1

From the docs

Google Play’s Dynamic Delivery uses your Android App Bundle to build and serve APKs that are optimized for each device configuration. This results in a smaller app download for end-users by removing unused code and resources needed for other devices.

So basically apk will be build using Dynamic delivery which will combine only necessary resources and will ensure that the build installed on particular design is optimized. There is no mention that bundle size is smaller, but it ensures that download size for end user will be less.

Also this a good article to refer to.

Mentionig some key points mentioned in it

• Step 1: You write all your code for your app in an IDE such as Android Studio or a games engine such as Unity as you normally would.
• Step 2: Now, when you’re ready to test or release the app, you build it as an Android App Bundle, Android’s new app publishing format. You still sign the app so that Google Play can verify it’s from you.
• Step 3: If you haven’t already, you opt in to app signing by Google Play. If you’re releasing a new app, you can do this in a one-click process when you upload your app. When you opt in, Play designates the first key you used to sign your app bundle as the upload key. This is just for security identification purposes and, if you ever lose it, you can contact Google to verify your identity and reset it. For existing apps, you need to visit the app signing page in the Play Console and securely transfer your app signing key to Google Play. Why do you need to do this? Continue to step 4 to find out.
• Step 4: When you upload your app bundle to Google Play, Play processes it and generates split APKs signed with the app signing key for every possible device configuration and language that you support. Split APKs are an Android platform feature introduced in Android L. As long as each split APK is signed with the same key, the Android platform will treat them as one app. You can think of a split APK as ‘part’ of an APK: to run the app, the device treats all the parts as a single app.
• Step 5: When a user installs the app, Play delivers the base split APK (all the code that’s common for every device), the language split APKs (for the languages the user speaks), and the device
  configuration split APKs (for the device’s screen size and the CPU
  architecture). This means the device gets just what it needs without
  wasted space. For updates to be accepted by the device, every
  release’s split APKs must be signed with the same app signing key as
  the original app install.