fix(Android, Stack v4): fix keyboard navigation focus for form sheet

android/src/main/java/com/swmansion/rnscreens/Screen.kt

@@ -3,6 +3,7 @@ package com.swmansion.rnscreens
 import android.annotation.SuppressLint
 import android.content.pm.ActivityInfo
 import android.graphics.Paint
+import android.os.Build
 import android.os.Parcelable
 import android.util.SparseArray
 import android.view.MotionEvent
@@ -11,6 +12,7 @@ import android.view.ViewGroup
 import android.view.WindowManager
 import android.webkit.WebView
 import android.widget.ImageView
+import androidx.annotation.RequiresApi
 import androidx.coordinatorlayout.widget.CoordinatorLayout
 import androidx.core.view.children
 import androidx.fragment.app.Fragment
@@ -345,6 +347,35 @@ class Screen(
         this.headerConfig?.toolbar?.importantForAccessibility = mode
     }
 
+    // Accepts one of 3 focusable flags and one of 3 descendantFocusability flags.
+    // https://developer.android.com/reference/android/view/View#setFocusable(int)
+    // https://developer.android.com/reference/android/view/ViewGroup#setDescendantFocusability(int)
+    @RequiresApi(Build.VERSION_CODES.O)
+    fun changeFocusability(
+        focusable: Int,
+        descendantFocusability: Int,
+    ) {
+        this.focusable = focusable
+        this.headerConfig?.toolbar?.focusable = focusable
+
+        this.descendantFocusability = descendantFocusability
+        this.headerConfig?.toolbar?.descendantFocusability = descendantFocusability
+    }
+
+    // Accepts boolean for focusability and one of 3 descendantFocusability flags.
+    // This method is provided for compatibility reasons only (SDK_API <= 25).
+    // https://developer.android.com/reference/android/view/ViewGroup#setDescendantFocusability(int)
+    fun changeFocusabilityCompat(
+        focusable: Boolean,
+        descendantFocusability: Int,
+    ) {
+        this.setFocusable(focusable)
+        this.headerConfig?.toolbar?.setFocusable(focusable)
+
+        this.descendantFocusability = descendantFocusability
+        this.headerConfig?.toolbar?.descendantFocusability = descendantFocusability
+    }
+
     var statusBarStyle: String? = null
         set(statusBarStyle) {
             if (statusBarStyle != null) {

android/src/main/java/com/swmansion/rnscreens/ScreenStack.kt

@@ -262,6 +262,7 @@ class ScreenStack(
                 transaction.add(id, newTop.fragment)
             }
 
+            val previousTopScreen: Screen? = topScreenWrapper?.screen
             topScreenWrapper = newTop as? ScreenStackFragmentWrapper
             stack.clear()
             stack.addAll(screenWrappers.asSequence().map { it as ScreenStackFragmentWrapper })
@@ -279,6 +280,13 @@ class ScreenStack(
                     .toList()
 
             turnOffA11yUnderTransparentScreen(visibleBottom)
+
+            // When form sheet is pushed to the top of the stack, we need to make sure that keyboard
+            // focus doesn't stay on the previous screen. We don't use requestFocus on newTop's
+            // screen because if there is an input field in the form sheet, it works as if autoFocus
+            // was enabled on the input field instead of focusing e.g. button above the input.
+            previousTopScreen?.clearFocus()
+
             transaction.commitNowAllowingStateLoss()
         }
     }
@@ -296,6 +304,20 @@ class ScreenStack(
                             IMPORTANT_FOR_ACCESSIBILITY_NO_HIDE_DESCENDANTS,
                         )
 
+                        // Keyboard navigation focus is separate from screen reader focus, that's
+                        // why we need to use focusable and descendantFocusability.
+                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+                            fragmentWrapper.screen.changeFocusability(
+                                NOT_FOCUSABLE,
+                                FOCUS_BLOCK_DESCENDANTS,
+                            )
+                        } else {
+                            fragmentWrapper.screen.changeFocusabilityCompat(
+                                false,
+                                FOCUS_BLOCK_DESCENDANTS,
+                            )
+                        }
+
                         // don't change a11y below non-transparent screens
                         if (fragmentWrapper == visibleBottom) {
                             break
@@ -306,6 +328,11 @@ class ScreenStack(
         }
 
         topScreen?.changeAccessibilityMode(IMPORTANT_FOR_ACCESSIBILITY_AUTO)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            topScreen?.changeFocusability(FOCUSABLE_AUTO, FOCUS_BEFORE_DESCENDANTS)
+        } else {
+            topScreen?.changeFocusabilityCompat(true, FOCUS_BEFORE_DESCENDANTS)
+        }
     }
 
     override fun notifyContainerUpdate() {

android/src/main/java/com/swmansion/rnscreens/bottomsheet/DimmingView.kt

@@ -31,6 +31,7 @@ internal class DimmingView(
 
     init {
         pointerEventsProxy.pointerEventsImpl = DimmingViewPointerEventsImpl(this)
+        setFocusable(false)
     }
 
     internal val blockGestures