fix(Android): fix formSheet not adjusting for keyboard when it contains input with autofocus (#2911)

## Description

Sometimes, formSheet that contains input with autoFocus would not
account for the keyboard and would remain behind it. This is because
`SheetDelegate` is set as a `OnApplyWindowInsetsListener` when fragment
is resumed - this happens after finishing formSheet entering animations
(animators impact fragment lifecycle). Sometimes, IME insets were
applied before this handler was set. Now, we can use
`WindowInsetsAnimationCallback` added in [this
PR](#2909).
Its `onPrepare` method is called before `onApplyWindowInsets` therefore
making it possible to set `OnApplyWindowInsetsListener` in time.

## Changes

- change `insetsObserverProxy`'s `listeners` to `HashSet` (we might try
to add the same listener multiple times)
- override `onPrepare` method in `WindowInsetsAnimationCallback`
- change visibility of `SheetDelegate` to `internal`

## Test code and steps to reproduce

Open `Test2895` screen in the example app, open & close the formSheet
(multiple times).

## Checklist

- [x] Included code example that can be used to test this change
- [x] Ensured that CI passes

Author: kligarski

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

@@ -10,7 +10,7 @@ import com.facebook.react.bridge.ReactApplicationContext
 import java.lang.ref.WeakReference
 
 object InsetsObserverProxy : OnApplyWindowInsetsListener, LifecycleEventListener {
-    private val listeners: ArrayList<OnApplyWindowInsetsListener> = arrayListOf()
+    private val listeners: HashSet<OnApplyWindowInsetsListener> = hashSetOf()
     private var eventSourceView: WeakReference<View> = WeakReference(null)
 
     // Please note semantics of this property. This is not `isRegistered`, because somebody, could unregister

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

@@ -31,6 +31,7 @@ import com.swmansion.rnscreens.bottomsheet.useSingleDetent
 import com.swmansion.rnscreens.bottomsheet.usesFormSheetPresentation
 import com.swmansion.rnscreens.events.HeaderHeightChangeEvent
 import com.swmansion.rnscreens.events.SheetDetentChangedEvent
+import com.swmansion.rnscreens.ext.asScreenStackFragment
 import com.swmansion.rnscreens.ext.parentAsViewGroup
 
 @SuppressLint("ViewConstructor") // Only we construct this view, it is never inflated.
@@ -541,6 +542,22 @@ class Screen(
         }
     }
 
+    override fun onAttachedToWindow() {
+        super.onAttachedToWindow()
+
+        // Insets handler for formSheet is added onResume but it is often too late if we use input
+        // with autofocus - onResume is called after finishing animator animation.
+        // onAttachedToWindow is called before onApplyWindowInsets so we use it to set the handler
+        // earlier. More details: https://github.com/software-mansion/react-native-screens/pull/2911
+        if (usesFormSheetPresentation()) {
+            fragment?.asScreenStackFragment()?.sheetDelegate?.let {
+                InsetsObserverProxy.addOnApplyWindowInsetsListener(
+                    it,
+                )
+            }
+        }
+    }
+
     private fun dispatchSheetDetentChanged(
         detentIndex: Int,
         isStable: Boolean,

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

@@ -74,7 +74,7 @@ class ScreenStackFragment :
 
     private var dimmingDelegate: DimmingViewManager? = null
 
-    private var sheetDelegate: SheetDelegate? = null
+    internal var sheetDelegate: SheetDelegate? = null
 
     @SuppressLint("ValidFragment")
     constructor(screenView: Screen) : super(screenView)

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

@@ -175,24 +175,16 @@ class SheetDelegate(
             }
 
             is KeyboardVisible -> {
-                val newMaxHeight =
-                    if (behavior.maxHeight - keyboardState.height > 1) {
-                        behavior.maxHeight - keyboardState.height
-                    } else {
-                        behavior.maxHeight
-                    }
                 when (screen.sheetDetents.count()) {
                     1 ->
                         behavior.apply {
-                            useSingleDetent(height = newMaxHeight)
                             addBottomSheetCallback(keyboardHandlerCallback)
                         }
 
                     2 ->
                         behavior.apply {
                             useTwoDetents(
                                 state = BottomSheetBehavior.STATE_EXPANDED,
-                                secondHeight = newMaxHeight,
                             )
                             addBottomSheetCallback(keyboardHandlerCallback)
                         }
@@ -202,7 +194,6 @@ class SheetDelegate(
                             useThreeDetents(
                                 state = BottomSheetBehavior.STATE_EXPANDED,
                             )
-                            maxHeight = newMaxHeight
                             addBottomSheetCallback(keyboardHandlerCallback)
                         }
 

android/src/main/java/com/swmansion/rnscreens/ext/FragmentExt.kt

@@ -0,0 +1,6 @@
+package com.swmansion.rnscreens.ext
+
+import androidx.fragment.app.Fragment
+import com.swmansion.rnscreens.ScreenStackFragment
+
+internal fun Fragment.asScreenStackFragment() = this as ScreenStackFragment