fix WebView offset when navigation bar enabled and keyboard visible (#5931)

Task/Issue URL:
https://app.asana.com/1/137249556945/project/1208671518894266/task/1210010551182684?focus=true

### Description
Fixes an issue where navigation bar, even when gone when keyboard is
inflated, would still retain the offset applied to the web view content.

The fix is to notify the coordinator layout that navigation bar changed,
when its visibility changes, which doesn't happen by default.

We already have handling of that available in the behavior that adjusts
browsers padding:


https://github.com/duckduckgo/Android/blob/c0e22478de53029ceb4f6f80188c97782a74562a/app/src/main/java/com/duckduckgo/app/browser/webview/BrowserContainerLayoutBehavior.kt#L53-L78

Furthermore I'm fixing the issue where `browserLayout` wasn't observing the bottom omnibar directly. Instead, it synced its offset with transitions in `BottomAppBarBehavior`, which only responds to web view scrolls. As a result, changes to the omnibar triggered by other sources were ignored.

The bottom omnibar includes the bottom navigation bar, which we hide when the keyboard appears. This alters the omnibar's size, but since `BottomAppBarBehavior` only reacted to scroll events, it didn’t update the web view's padding/margin accordingly.

I removed the hardcoded `browserLayout` adjustments tied to `BottomAppBarBehavior`. Instead, I updated `BrowserContainerLayoutBehavior` to apply correct padding for all bottom omnibar changes, whether triggered by scroll or size adjustments.

Author: LukasPaczos

app/src/main/java/com/duckduckgo/app/browser/navigation/bar/BrowserNavigationBarViewIntegration.kt

@@ -29,6 +29,7 @@ import com.duckduckgo.common.ui.view.show
 import com.duckduckgo.common.utils.keyboardVisibilityFlow
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.launch
 
 /**
@@ -88,11 +89,14 @@ class BrowserNavigationBarViewIntegration(
         // we're hiding the navigation bar when keyboard is shown,
         // to prevent it from being "pushed up" within the coordinator layout
         keyboardVisibilityJob = lifecycleScope.launch {
-            omnibar.textInputRootView.keyboardVisibilityFlow().collect { keyboardVisible ->
+            omnibar.textInputRootView.keyboardVisibilityFlow().distinctUntilChanged().collect { keyboardVisible ->
                 if (keyboardVisible) {
                     navigationBarView.gone()
                 } else {
-                    navigationBarView.show()
+                    navigationBarView.postDelayed(
+                        { navigationBarView.show() },
+                        BrowserTabFragment.KEYBOARD_DELAY,
+                    )
                 }
             }
         }

app/src/main/java/com/duckduckgo/app/browser/navigation/bar/view/BrowserNavigationBarView.kt

@@ -45,6 +45,7 @@ import com.duckduckgo.app.browser.navigation.bar.view.BrowserNavigationBarViewMo
 import com.duckduckgo.app.browser.navigation.bar.view.BrowserNavigationBarViewModel.ViewState
 import com.duckduckgo.app.browser.omnibar.experiments.FadeOmnibarLayout
 import com.duckduckgo.app.browser.omnibar.model.OmnibarPosition
+import com.duckduckgo.app.browser.webview.BrowserContainerLayoutBehavior
 import com.duckduckgo.common.ui.viewbinding.viewBinding
 import com.duckduckgo.common.utils.ConflatedJob
 import com.duckduckgo.common.utils.ViewViewModelFactory
@@ -62,6 +63,22 @@ class BrowserNavigationBarView @JvmOverloads constructor(
     defStyle: Int = 0,
 ) : FrameLayout(context, attrs, defStyle), AttachedBehavior {
 
+    override fun setVisibility(visibility: Int) {
+        val isVisibilityUpdated = this.visibility != visibility
+
+        super.setVisibility(visibility)
+
+        /**
+         * This notifies all view behaviors that depend on the [BrowserNavigationBarView] to recalculate whenever the bar's visibility changes,
+         * for example, we require that in [BrowserContainerLayoutBehavior] to remove the bottom inset when navigation bar disappears.
+         * The base coordinator behavior doesn't notify dependent views when visibility changes, so we need to do that manually.
+         */
+        val parent = parent
+        if (isVisibilityUpdated && parent is CoordinatorLayout) {
+            parent.dispatchDependentViewsChanged(this)
+        }
+    }
+
     @Inject
     lateinit var viewModelFactory: ViewViewModelFactory
 

app/src/main/java/com/duckduckgo/app/browser/omnibar/BottomAppBarBehavior.kt

@@ -23,7 +23,6 @@ import android.util.AttributeSet
 import android.view.Gravity
 import android.view.View
 import android.view.animation.DecelerateInterpolator
-import android.widget.RelativeLayout
 import androidx.coordinatorlayout.widget.CoordinatorLayout
 import androidx.core.view.ViewCompat
 import androidx.core.view.ViewCompat.NestedScrollType
@@ -46,17 +45,13 @@ class BottomAppBarBehavior<V : View>(
     private var lastStartedType: Int = 0
     private var offsetAnimator: ValueAnimator? = null
 
-    private var browserLayout: RelativeLayout? = null
-
     @SuppressLint("RestrictedApi")
     override fun layoutDependsOn(parent: CoordinatorLayout, child: V, dependency: View): Boolean {
         if (dependency is Snackbar.SnackbarLayout) {
             updateSnackbar(child, dependency)
         }
 
-        if (dependency.id == R.id.browserLayout) {
-            browserLayout = dependency as RelativeLayout
-        } else if (dependency.id != R.id.webViewFullScreenContainer) {
+        if (dependency.id != R.id.webViewFullScreenContainer) {
             offsetBottomByToolbar(dependency)
         }
 
@@ -95,7 +90,6 @@ class BottomAppBarBehavior<V : View>(
             // only hide the app bar in the browser layout
             if (target.id == R.id.browserWebView) {
                 toolbar.translationY = max(0f, min(toolbar.height.toFloat(), toolbar.translationY + dy))
-                offsetBottomByToolbar(browserLayout)
             }
         }
     }
@@ -132,7 +126,6 @@ class BottomAppBarBehavior<V : View>(
         } else {
             val targetTranslation = if (expanded) 0f else omnibar.height().toFloat()
             omnibar.setTranslation(targetTranslation)
-            offsetBottomByToolbar(browserLayout)
         }
     }
 
@@ -149,7 +142,6 @@ class BottomAppBarBehavior<V : View>(
         offsetAnimator?.addUpdateListener { animation ->
             val animatedValue = animation.animatedValue as Float
             omnibar.setTranslation(animatedValue)
-            offsetBottomByToolbar(browserLayout)
         }
 
         val targetTranslation = if (isVisible) 0f else omnibar.height().toFloat()

app/src/main/java/com/duckduckgo/app/browser/webview/BrowserContainerLayoutBehavior.kt

@@ -20,18 +20,21 @@ import android.content.Context
 import android.util.AttributeSet
 import android.view.View
 import androidx.coordinatorlayout.widget.CoordinatorLayout
-import androidx.core.view.isVisible
+import androidx.core.view.isGone
 import com.duckduckgo.app.browser.navigation.bar.view.BrowserNavigationBarView
+import com.duckduckgo.app.browser.omnibar.OmnibarLayout
+import com.duckduckgo.app.browser.omnibar.model.OmnibarPosition
 import com.google.android.material.appbar.AppBarLayout.ScrollingViewBehavior
 
 /**
- * A [ScrollingViewBehavior] that additionally observes the position of [BrowserNavigationBarView], if present,
- * and applies bottom padding to the target view equal to the visible height of the navigation bar.
+ * A [ScrollingViewBehavior] that additionally observes the position of [BrowserNavigationBarView] or bottom [OmnibarLayout], if present,
+ * and applies bottom padding to the target view equal to the visible height of the bottom element.
  *
- * This prevents the navigation bar from overlapping with, for example, content found in the web view.
+ * This prevents the bottom element from overlapping with, for example, content found in the web view.
  *
- * Note: This behavior is intended for use with the top omnibar. When the bottom omnibar is used,
- * it already includes the navigation bar, so no additional coordination is required.
+ * Note: [BrowserNavigationBarView] or bottom [OmnibarLayout] will never be children of the coordinator layout at the same time, so they won't be competing for updates:
+ * - When top [OmnibarLayout] is used, [BrowserNavigationBarView] is added directly to the coordinator layout.
+ * - When bottom [OmnibarLayout] is used, it comes embedded with the [BrowserNavigationBarView].
  */
 class BrowserContainerLayoutBehavior(
     context: Context,
@@ -43,23 +46,19 @@ class BrowserContainerLayoutBehavior(
         child: View,
         dependency: View,
     ): Boolean {
-        return if (dependency is BrowserNavigationBarView) {
-            true
-        } else {
-            super.layoutDependsOn(parent, child, dependency)
-        }
+        return dependency.isBrowserNavigationBar() || dependency.isBottomOmnibar() || super.layoutDependsOn(parent, child, dependency)
     }
 
     override fun onDependentViewChanged(
         parent: CoordinatorLayout,
         child: View,
         dependency: View,
     ): Boolean {
-        return if (dependency is BrowserNavigationBarView) {
-            val newBottomPadding = if (dependency.isVisible) {
-                dependency.measuredHeight - dependency.translationY.toInt()
-            } else {
+        return if (dependency.isBrowserNavigationBar() || dependency.isBottomOmnibar()) {
+            val newBottomPadding = if (dependency.isGone) {
                 0
+            } else {
+                dependency.measuredHeight - dependency.translationY.toInt()
             }
             if (child.paddingBottom != newBottomPadding) {
                 child.setPadding(
@@ -76,4 +75,7 @@ class BrowserContainerLayoutBehavior(
             super.onDependentViewChanged(parent, child, dependency)
         }
     }
+
+    private fun View.isBrowserNavigationBar(): Boolean = this is BrowserNavigationBarView
+    private fun View.isBottomOmnibar(): Boolean = this is OmnibarLayout && this.omnibarPosition == OmnibarPosition.BOTTOM
 }