fix(SystemBars): respect windowSoftInputMode="adjustNothing"

[piotrblasiak]

Description

Supersedes #8612 (I deleted the fork that PR was opened from, so it can no longer be updated). Reworked after the discussion there: no new config option, the behavior is keyed off the manifest instead.

When the activity declares android:windowSoftInputMode="adjustNothing", SystemBars now treats the keyboard as not there:

• the webview is not padded by the IME inset, so the keyboard overlays it
• the IME insets handed to the WebView are set to 0 (not consumed, see https://issues.chromium.org/issues/461332423)

The mode is read from the window's softInputMode on every insets pass, so a later setSoftInputMode() is respected as well. Nothing changes for adjustResize, adjustPan or an unset mode.

Why the IME insets are zeroed and not passed through

WebView >= 139 shrinks its visual viewport for the IME insets it receives (docs), which makes the whole page pannable above the keyboard. In Chrome a page can opt out of that with navigator.virtualKeyboard.overlaysContent = true or interactive-widget=overlays-content, but WebView ignores both: Chrome implements the opt-out in its own embedder code (ApplicationViewportInsetTracker), while the WebView path (AwDisplayCutoutController / AwViewAndroidDelegate.getViewportInsetBottom()) applies the inset unconditionally and never looks at the keyboard mode. So the only opt-out in a WebView is the native one from the Android guide: not handing it the IME insets.

The keyboard height stays available to the app through @capacitor/keyboard, which reads the root window insets.

Change Type

• Fix
• Feature
• Refactor
• Breaking Change
• Documentation

Rationale / Problems Fixed

closes #8611

Since #8384 (8.3.0) the webview is always resized for the keyboard, even when the activity declares android:windowSoftInputMode="adjustNothing". Apps that keep content clear of the keyboard themselves, using the height from @capacitor/keyboard as they do on iOS with resize: "none", then account for the keyboard twice.

Tests or Reproductions

Reproduction: see #8611.

On a Zebra TC58 (Android 15, Android System WebView 151.0.7922.199):

• Skipping only the padding and passing the IME insets through, with navigator.virtualKeyboard.overlaysContent = true set in the page: the page still pans above the keyboard. The same page in Chrome on the same device does not.
• Skipping the padding and zeroing the IME insets (the inset handling of feat(SystemBars): add keyboardInsetsHandling option to let the keyboard overlay the webview #8612, which is unchanged here): window.innerHeight and visualViewport.height stay unchanged, the page cannot be panned, and keyboardWillShow / keyboardWillHide still fire with the correct height.

The softInputMode detection that replaces the config option has not been run on a device yet, I will confirm here once it has.

Platforms Affected

• Android
• iOS
• Web