Fix sheets to work nicely on ios 15 (#5685)

modules/bottom-sheet/ios/SheetViewController.swift

@@ -27,29 +27,39 @@ class SheetViewController: UIViewController {
       return
     }
 
+    if #available(iOS 16.0, *) {
       if contentHeight > screenHeight - 100 {
         sheet.detents = [
           .large()
         ]
         sheet.selectedDetentIdentifier = .large
       } else {
-      if #available(iOS 16.0, *) {
         sheet.detents = [
           .custom { _ in
             return contentHeight
           }
         ]
-      } else {
-        sheet.detents = [
-          .medium()
-        ]
-      }
-
         if !preventExpansion {
           sheet.detents.append(.large())
         }
         sheet.selectedDetentIdentifier = .medium
       }
+    } else {
+      if contentHeight > screenHeight / 2 {
+        sheet.detents = [
+          .large()
+        ]
+        sheet.selectedDetentIdentifier = .large
+      } else {
+        sheet.detents = [
+          .medium()
+        ]
+        if !preventExpansion {
+          sheet.detents.append(.large())
+        }
+        sheet.selectedDetentIdentifier = .medium
+      }
+    }
   }
 
   func updateDetents(contentHeight: CGFloat, preventExpansion: Bool) {

modules/bottom-sheet/src/BottomSheetNativeComponent.tsx

@@ -23,10 +23,13 @@ const NativeView: React.ComponentType<
 
 const NativeModule = requireNativeModule('BottomSheet')
 
+const isIOS15 = Platform.OS === 'ios' && Number(Platform.Version) < 16
+
 export class BottomSheetNativeComponent extends React.Component<
   BottomSheetViewProps,
   {
     open: boolean
+    viewHeight?: number
   }
 > {
   ref = React.createRef<any>()
@@ -67,6 +70,19 @@ export class BottomSheetNativeComponent extends React.Component<
     const {children, backgroundColor, ...rest} = this.props
     const cornerRadius = rest.cornerRadius ?? 0
 
+    let extraStyles
+    if (isIOS15 && this.state.viewHeight) {
+      const {viewHeight} = this.state
+      if (viewHeight < screenHeight / 2) {
+        extraStyles = {
+          height: viewHeight,
+          marginTop: screenHeight / 2 - viewHeight,
+          borderTopLeftRadius: cornerRadius,
+          borderTopRightRadius: cornerRadius,
+        }
+      }
+    }
+
     if (!this.state.open) {
       return null
     }
@@ -92,8 +108,14 @@ export class BottomSheetNativeComponent extends React.Component<
               borderTopLeftRadius: cornerRadius,
               borderTopRightRadius: cornerRadius,
             },
+            extraStyles,
           ]}>
-          <View onLayout={this.updateLayout}>
+          <View
+            onLayout={e => {
+              const {height} = e.nativeEvent.layout
+              this.setState({viewHeight: height})
+              this.updateLayout()
+            }}>
             <BottomSheetPortalProvider>{children}</BottomSheetPortalProvider>
           </View>
         </View>