kelvin.dart

Started using React Native two days ago and immediately fell down a tab-bar rabbit hole. I’d seen Instagram and Revolut collapse their tab bars on scroll while keeping every icon visible. I wanted that without giving up real iOS Liquid Glass. Turns out iOS 26’s public API can’t express that state. UITabBarMinimizeBehavior is an enum of when, not what. With onScrollDown, UIKit minimizes the bar to the active tab alone. There’s no parameter controlling what survives. So most implementations rebuild the visible bar as a custom component. Some use genuine glass materials, but the real UITabBar is gone and with it, the native selection capsule: that little blob that moves like a drop of water between tabs. You can reproduce it with separate springs on the leading and trailing edges. I didn’t want a reproduction. I wanted UIKit’s. Then I remembered a Flutter app i built some months back which uses cupertino_native. Flutter runs the app while a platform-view bridge renders a real UIKit UITabBar. Finding expo-glass-tabs clarified the compact geometry I wanted. The two ideas clicked: why not bridge a real UITabBar into React Native? Here’s the trick: a standalone UITabBar has no UITabBarController managing it, so Apple’s minimization rule never applies. That means I can control its frame and items myself. Expo Router still owns navigation and screen lifecycle. React Native detects scroll direction. Swift removes and restores the real item labels, recentres the icons and animates the native bar’s size. All five icons remain visible. The result keeps Apple’s Liquid Glass, water-drop capsule, hit testing and accessibility, while adding a compact state its public API doesn’t provide. One gotcha tho: detaching the bar means reimplementing everything the controller previously gave you for free. Active-tab reselect scrolling was one example

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