@cdmint/react-native-tab-view
v2.0.3
Published
Tab view component for React Native
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React Native Tab View
A cross-platform Tab View component for React Native.
- Run the example app to see it in action.
- Checkout the example/ folder for source code.
Features
- Smooth animations and gestures
- Scrollable tabs
- Supports both top and bottom tab bars
- Follows Material Design spec
- Highly customizable
- Fully typed with Flow
Demo
Installation
Open a Terminal in the project root and run:
yarn add react-native-tab-view
If you are using Expo, you are done. Otherwise, continue to the next step.
Install and link react-native-gesture-handler
and react-native-reanimated
. To install and link them, run:
yarn add react-native-reanimated react-native-gesture-handler
react-native link react-native-reanimated
react-native link react-native-gesture-handler
IMPORTANT: There are additional steps required for react-native-gesture-handler
on Android after running react-native link react-native-gesture-handler
. Check the this guide to complete the installation.
Quick Start
import * as React from 'react';
import { View, StyleSheet, Dimensions } from 'react-native';
import { TabView, SceneMap } from 'react-native-tab-view';
const FirstRoute = () => (
<View style={[styles.scene, { backgroundColor: '#ff4081' }]} />
);
const SecondRoute = () => (
<View style={[styles.scene, { backgroundColor: '#673ab7' }]} />
);
export default class TabViewExample extends React.Component {
state = {
index: 0,
routes: [
{ key: 'first', title: 'First' },
{ key: 'second', title: 'Second' },
],
};
render() {
return (
<TabView
navigationState={this.state}
renderScene={SceneMap({
first: FirstRoute,
second: SecondRoute,
})}
onIndexChange={index => this.setState({ index })}
initialLayout={{ width: Dimensions.get('window').width }}
/>
);
}
}
const styles = StyleSheet.create({
scene: {
flex: 1,
},
});
More examples on Snack
Integration with React Navigation
React Navigation integration can be achieved by the react-navigation-tabs package. Note that while it's easier to use, it is not as flexible as using the library directly.
API reference
The package exports a TabView
component which is the one you'd use to render the tab view, and a TabBar
component which is the default tab bar implementation.
TabView
Container component responsible for rendering and managing tabs. Follows material design styles by default.
Basic usage look like this:
<TabView
navigationState={this.state}
onIndexChange={index => this.setState({ index })}
renderScene={SceneMap({
first: FirstRoute,
second: SecondRoute,
})}
/>
Props
navigationState
(required
)
State for the tab view. The state should contain the following properties:
index
: a number representing the index of the active route in theroutes
arrayroutes
: an array containing a list of route objects used for rendering the tabs
Each route object should contain the following properties:
key
: a unique key to identify the route (required)title
: title for the route to display in the tab baricon
: icon for the route to display in the tab baraccessibilityLabel
: accessibility label for the tab buttontestID
: test id for the tab button
Example:
{
index: 1,
routes: [
{ key: 'music', title: 'Music' },
{ key: 'albums', title: 'Albums' },
{ key: 'recents', title: 'Recents' },
{ key: 'purchased', title: 'Purchased' },
]
}
TabView
is a controlled component, which means the index
needs to be updated via the onIndexChange
callback.
onIndexChange
(required
)
Callback which is called on tab change, receives the index of the new tab as argument. The navigation state needs to be updated when it's called, otherwise the change is dropped.
renderScene
(required
)
Callback which returns a react element to render as the page for the tab. Receives an object containing the route as the argument:
renderScene = ({ route, jumpTo }) => {
switch (route.key) {
case 'music':
return <MusicRoute jumpTo={jumpTo} />;
case 'albums':
return <AlbumsRoute jumpTo={jumpTo} />;
}
};
You need to make sure that your individual routes implement a shouldComponentUpdate
to improve the performance. To make it easier to specify the components, you can use the SceneMap
helper.
SceneMap
takes an object with the mapping of route.key
to React components and returns a function to use with renderScene
prop.
import { SceneMap } from 'react-native-tab-view';
...
renderScene = SceneMap({
music: MusicRoute,
albums: AlbumsRoute,
});
Specifying the components this way is easier and takes care of implementing a shouldComponentUpdate
method.
Each scene receives the following props:
route
: the current route rendered by the componentjumpTo
: method to jump to other tabs, takes aroute.key
as it's argument
The jumpTo
method can be used to navigate to other tabs programmatically:
this.props.jumpTo('albums');
All the scenes rendered with SceneMap
are optimized using React.PureComponent
and don't re-render when parent's props or states change. If you need more control over how your scenes update (e.g. - triggering a re-render even if the navigationState
didn't change), use renderScene
directly instead of using SceneMap
.
IMPORTANT: Do not pass inline functions to SceneMap
, for example, don't do the following:
SceneMap({
first: () => <FirstRoute foo={this.props.foo} />,
second: SecondRoute,
});
Always define your components elsewhere in the top level of the file. If you pass inline functions, it'll re-create the component every render, which will cause the entire route to unmount and remount every change. It's very bad for performance and will also cause any local state to be lost.
renderTabBar
Callback which returns a custom React Element to use as the tab bar:
import { TabBar } from 'react-native-tab-view';
...
renderTabBar = props => <TabBar {...props} />;
If this is not specified, the default tab bar is rendered. You pass this props to customize the default tab bar, provide your own tab bar, or disable the tab bar completely.
renderTabBar = () => null;
tabBarPosition
Position of the tab bar in the tab view. Possible values are 'top'
and 'bottom'
. Defaults to 'top'
.
lazy
Boolean indicating whether to lazily render the scenes. By default all scenes are rendered to provide a smoother swipe experience. But you might want to defer the rendering of unfocused scenes until the user sees them. To enable lazy rendering, set lazy
to true
.
When you enable lazy
, the unfocused screens will usually take some time to render when they come into focus. You can use the renderLazyPlaceholder
prop to customize what the user sees during this short period.
renderLazyPlaceholder
Callback which returns a custom React Element to render for routes that haven't been rendered yet. Receives an object containing the route as the argument. The lazy
prop also needs to be enabled.
This view is usually only shown for a split second. Keep it lightweight.
By default, this renders null
.
removeClippedSubviews
Boolean indicating whether to remove invisible views (such as unfocused screens) from the native view hierarchy to improve memory usage. Defaults to false
.
Note: Don't enable this on iOS where this is buggy and views don't re-appear.
keyboardDismissMode
String indicating whether the keyboard gets dismissed in response to a drag gesture. Possible values are:
'on-drag'
(default): the keyboard is dismissed when a drag begins.'none'
: drags do not dismiss the keyboard.
swipeEnabled
Boolean indicating whether to enable swipe gestures. Swipe gestures are enabled by default. Passing false
will disable swipe gestures, but the user can still switch tabs by pressing the tab bar.
swipeDistanceThreshold
Minimum swipe distance which triggers a tab switch. By default, this is automatically determined based on the screen width.
swipeVelocityThreshold
Minimum swipe velocity which triggers a tab switch. Defaults to 1200
.
onSwipeStart
Callback which is called when the swipe gesture starts, i.e. the user touches the screen and moves it.
onSwipeEnd
Callback which is called when the swipe gesture ends, i.e. the user lifts their finger from the screen after the swipe gesture.
initialLayout
Object containing the initial height and width of the screens. Passing this will improve the initial rendering performance. For most apps, this is a good default:
{ width: Dimensions.get('window').width }}
sceneContainerStyle
Style to apply to the view wrapping each screen. You can pass this to override some default styles such as overflow clipping:
style
Style to apply to the tab view container.
TabBar
Material design themed tab bar. To customize the tab bar, you'd need to use the renderTabBar
prop of TabView
to render the TabBar
and pass additional props.
For example, to customize the indicator color and the tab bar background color, you can pass indicatorStyle
and style
props to the TabBar
respectively:
renderTabBar={props =>
<TabBar
{...props}
indicatorStyle={{ backgroundColor: 'white' }}
style={{ backgroundColor: 'pink' }}
/>
}
Props
getLabelText
Function which takes an object with the current route and returns the label text for the tab. Uses route.title
by default.
getLabelText={({ route }) => route.title}
getAccessible
Function which takes an object with the current route and returns a boolean to indicate whether to mark a tab as accessible
. Defaults to true
.
getAccessibilityLabel
Function which takes an object with the current route and returns a accessibility label for the tab button. Uses route.accessibilityLabel
by default if specified, otherwise uses the route title.
getAccessibilityLabel={({ route }) => route.accessibilityLabel}
testID
Function which takes an object with the current route and returns a test id for the tab button to locate this tab button in tests. Uses route.testID
by default.
getTestID={({ route }) => route.testID}
getAccessibilityLabel: (props: { route: T }) => string;
Get accessibility label for the tab button. This is read by the screen reader when the user taps the tab.
Uses route.accessibilityLabel
by default if specified, otherwise uses the route title.
getTestID: (props: { route: T }) => string | undefined;
Get the id to locate this tab button in tests, uses route.testID
by default.
renderIcon
Function which takes an object with the current route, focused status and color and returns a custom React Element to be used as a icon.
renderIcon={({ route, focused, color }) => (
<Icon
name={focused ? 'abums' : 'albums-outlined'}
color={color}
/>
)}
renderLabel
Function which takes an object with the current route, focused status and color and returns a custom React Element to be used as a label.
renderLabel={({ route, focused, color }) => (
<Text style={{ color, margin: 8 }}>
{route.title}
</Text>
)}
renderIndicator
Function which takes an object with the current route and returns a custom React Element to be used as a tab indicator.
renderBadge
Function which takes an object with the current route and returns a custom React Element to be used as a badge.
onTabPress
Function to execute on tab press. It receives the scene for the pressed tab, useful for things like scroll to top.
onTabLongPress
Function to execute on tab long press, use for things like showing a menu with more options
activeColor
Custom color for icon and label in the active tab.
inactiveColor
Custom color for icon and label in the inactive tab.
pressColor
Color for material ripple (Android >= 5.0 only).
pressOpacity
Opacity for pressed tab (iOS and Android < 5.0 only).
scrollEnabled
Boolean indicating whether to enable scrollable tabs.
bounces
Boolean indicating whether the tab bar bounces when scrolling.
tabStyle
Style to apply to the individual tab items in the tab bar.
indicatorStyle
Style to apply to the active indicator.
labelStyle
Style to apply to the tab item label.
contentContainerStyle
Style to apply to the inner container for tabs.
style
Style to apply to the tab bar container.
Optimization Tips
Avoid unnecessary re-renders
The renderScene
function is called every time the index changes. If your renderScene
function is expensive, it's good idea move each route to a separate component if they don't depend on the index, and apply shouldComponentUpdate
in your route components to prevent unnecessary re-renders.
For example, instead of:
renderScene = ({ route }) => {
switch (route.key) {
case 'home':
return (
<View style={styles.page}>
<Avatar />
<NewsFeed />
</View>
);
default:
return null;
}
};
Do the following:
renderScene = ({ route }) => {
switch (route.key) {
case 'home':
return <HomeComponent />;
default:
return null;
}
};
Where <HomeComponent />
is a PureComponent
:
export default class HomeComponent extends React.PureComponent {
render() {
return (
<View style={styles.page}>
<Avatar />
<NewsFeed />
</View>
);
}
}
Avoid one frame delay
We need to measure the width of the container and hence need to wait before rendering some elements on the screen. If you know the initial width upfront, you can pass it in and we won't need to wait for measuring it. Most of the time, it's just the window width.
For example, pass the following initialLayout
to TabView
:
const initialLayout = {
height: 0,
width: Dimensions.get('window').width,
};
The tab view will still react to changes in the dimension and adjust accordingly to accommodate things like orientation change.
Optimize large number of routes
If you've a large number of routes, especially images, it can slow the animation down a lot. You can instead render a limited number of routes.
For example, do the following to render only 2 routes on each side:
renderScene = ({ route }) => {
if (Math.abs(this.state.index - this.state.routes.indexOf(route)) > 2) {
return <View />;
}
return <MySceneComponent route={route} />;
};
Avoid rendering TabView inside ScrollView
Nesting the TabView
inside a vertical ScrollView
will disable the optimizations in the FlatList
components rendered inside the TabView
. So avoid doing it if possible.
Contributing
While developing, you can run the example app to test your changes.
Make sure your code passes Flow and ESLint. Run the following to verify:
yarn flow
yarn lint
To fix formatting errors, run the following:
yarn lint -- --fix
Remember to add tests for your change if possible.