![]() If you decide to use it in your project, let me know how it goes. I plan to integrate it into Exponent’s ExNavigation library so it’s easier to use. I still need to polish the styles to match the platform guidelines more closely. I update the release notes with breaking changes, so make sure to read them if you’re using the component. While it’s mostly stable, a few things might change in the future. Note that the project is still young, and the API not finished. The animations and gestures can be disabled, or tweaked using a custom panHandler if needed. It can be used as a top bar or a bottom bar. The TabBar is super customizable and supports icons, text, and custom indicator (the tiny line below the active tab). The README contains a simple example with Material Design themed tab bars. function isMovingHorzontally(evt, gestureState) In onMoveShouldSetResponder, which grants the gesture to our code, we check if the horizontal distance travelled and horizontal velocity are at least 3 times of the vertical distance and velocity. After some trial and error, I decided to go with the following check to determine horizontal movement. Since people often move their finger at an angle when scrolling, it’s easy to cause unintentional swipes. Using the PanResponder handlers we need to: Detect ‘mostly’ horizontal movement to trigger the swipe PanResponder is powerful and simple, but it’s really easy to make mistakes. ❤️Ĭheckout the React Native docs on Animations which covers this in detail. Animated is super-powerful and you can do so much using interpolation. The swipe, tab indicator and tab label opacity animation all track the Animated.Value, so they stay in sync.įinally, we add in the TabViewPage.StyleInterpolator to control the position of a tab based on state, using interpolation on the Animated.Value. Providing helper methods to nested components for changing and current position. ![]() Animating the position and updating tab components when navigation state changes, ensuring animation won’t stop midway due to a race condition.This value is available anywhere in the layout for controlling other animations. A single Animated.Value for everything means nothing will go out of sync. Providing an Animated.Value to control the gestures and animations.Measuring the layout, to properly position the pages and tab bar indicator.The TabViewTransitioner wraps everything. Put everything together in a wrapper component ![]() We avoid this by updating component state only after the animation finishes, as opposed to when the gesture finishes, which other solutions seem to do. Re-renders during the animation are costly and can produce jitter, since the animations run on the same javascript thread. When animating, we must strive to do as little work as possible to maintain 60 FPS. ![]() This is the trickiest part! So many things can go wrong. For example, a value of 1.5corresponds to halfway between the second and third tab. So the final implementation stores the index value, which can be a float. Storing the actual translate value as the Animated.Value made sense at first, but this meant other components tracking this value had to know about the container width. This position value will be updated and tracked often, by the tapping the navigation, and by swiping content, so it makes sense that we store it in an Animated.Value. Store the current position in an Animated.Value So we need to measure the width of the container using React Native’s built-in onLayout prop. The current page occupies the screen width. Let’s take a tour! Measure the width of the containerīy default, we position the pages in a horizontal view extending past the width of the screen. When broken down, the implementation is simple enough. Now, how hard could it be to implement this? I also found react-swipeable-views, which has a cross platform implementation (web, ios and android), but only after I set out to work on my own implementation of a tab view. However, I found it can drop frames, lacks customizability and uses a stateful API. I found react-native-scrollable-tab-view which was started by Brent Vatne and now maintained by Evgeniy Sokovikov.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |