bug: Android banner safe-area issues with Capacitor 8.5.2+ and different WebView versions

[luisbytes]

Describe the bug

After upgrading to Capacitor 8.5.2, the AdMob banner can have incorrect safe-area behavior depending on the Android version and Android System WebView version.

The issue can be reproduced with the standard adaptive banner configuration:

await AdMob.showBanner({
  adId: BANNER_AD_UNIT_ID,
  adSize: BannerAdSize.ADAPTIVE_BANNER,
  position: BannerAdPosition.BOTTOM_CENTER,
  isTesting: true,
});

This appears to be related to the safe-area / edge-to-edge changes introduced in Capacitor 8.5.2.

Capacitor 8.5.2 requirement

With Capacitor 8.5.2, EdgeToEdge.enable(this) also needs to be added to MainActivity:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    EdgeToEdge.enable(this);
}

Without this configuration, the application can have unexpected safe-area behavior.

The reproduction project already includes the required configuration and is ready to run:

https://github.com/luisbytes/admob-safearea-community

Capacitor 9

This is also relevant for Capacitor 9.

The Capacitor 9 changes that make edge-to-edge the default in the Android starter template and update the migration path for existing projects are already merged into next:

• feat(SystemBars): set default insets handling to 'native' ionic-team/capacitor#8599
• feat(cli): add android edge-to-edge settings to migrator ionic-team/capacitor#8604

These changes make EdgeToEdge.enable(this) part of the Android MainActivity template and update existing projects to the new edge-to-edge configuration.

However, this issue should also be patched for Capacitor 8.5.2+ and not be deferred until Capacitor 9. Projects using Capacitor 8.5.2 or later are already affected by this behavior today.

Because of this, it would be useful for @capacitor-community/admob to provide a fix for the current Capacitor 8.5.2+ behavior while also ensuring compatibility with the Capacitor 9 changes.

To Reproduce

1. Open the reproduction project:
   https://github.com/luisbytes/admob-safearea-community
2. Install the dependencies and run the Android application.
3. The project is already configured with Capacitor 8.5.2 and the required EdgeToEdge.enable(this) configuration.
4. Test the application using different Android System WebView versions.
5. Observe the position of the bottom adaptive AdMob banner.

The following behavior can be reproduced:

Android	WebView	Result	Screenshot
Android <= 14	WebView < 140	Works
Android <= 14	WebView >= 140	Banner is behind the navigation bar
Android >= 15	WebView < 140	Double safe-area padding
Android >= 15	WebView >= 140	Works

Expected behavior

The banner should always be positioned correctly above the Android navigation/gesture area without being covered or receiving the safe-area inset twice, regardless of the Android System WebView version.

Smartphone

• OS: Android 14 / Android 16
• WebView: 113 / 134 / 153
• Capacitor: 8.5.2
• AdMob: @capacitor-community/admob
• Ad size: BannerAdSize.ADAPTIVE_BANNER
• Position: BannerAdPosition.BOTTOM_CENTER
• Testing: true

Additional context

The important factor appears to be the Android System WebView version, rather than Android version alone.

The issue appears to be related to the safe-area / edge-to-edge refactor introduced in Capacitor 8.5.2 (ionic-team/capacitor#8535).

It would be good to address this in the current Capacitor 8 line rather than waiting for Capacitor 9, because applications using Capacitor 8.5.2+ can already encounter this issue depending on their Android System WebView version.

[luisbytes]

@rdlabo I don't see a way to fix this without dropping support for version 8.5.1 and earlier.

The safe area has been a headache in Capacitor since the introduction of target API level 35.

It wasn't until version 8.5.2 that we finally got something decent.

Would it be possible to release a new version of the plugin that supports the banner safe area only for version 8.5.2 and up?

I'm still trying to find a workaround.

[luisbytes]

@rdlabo Done, I created PR #469.

I tested it with Capacitor v8.5.1 and v8.5.2, across multiple Android and WebView versions. I also included evidence of the behavior.

The change was actually very simple: the insets are now applied directly to the native banner, without modifying the WebView or depending on its version.

Capacitor v8.5.1

Android	WebView < 140	WebView >= 140
Android 16
Android 14

Capacitor v8.5.2

Android	WebView < 140	WebView >= 140
Android 16
Android 14