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import React, {createRef, useState, useMemo} from 'react'
import {
Animated,
StyleSheet,
TouchableWithoutFeedback,
View,
} from 'react-native'
import {Text} from './text/Text'
import {usePalette} from 'lib/hooks/usePalette'
interface Layout {
x: number
width: number
}
export function TabBar({
selectedPage,
items,
position,
offset,
indicatorPosition = 'bottom',
indicatorColor,
onSelect,
}: {
selectedPage: number
items: string[]
position: Animated.Value
offset: Animated.Value
indicatorPosition?: 'top' | 'bottom'
indicatorColor?: string
onSelect?: (index: number) => void
}) {
const pal = usePalette('default')
const [itemLayouts, setItemLayouts] = useState<Layout[]>(
items.map(() => ({x: 0, width: 0})),
)
const itemRefs = useMemo(
() => Array.from({length: items.length}).map(() => createRef<View>()),
[items.length],
)
const panX = Animated.add(position, offset)
const indicatorStyle = {
backgroundColor: indicatorColor || pal.colors.link,
bottom: indicatorPosition === 'bottom' ? -1 : undefined,
top: indicatorPosition === 'top' ? -1 : undefined,
transform: [
{
translateX: panX.interpolate({
inputRange: items.map((_item, i) => i),
outputRange: itemLayouts.map(l => l.x + l.width / 2),
}),
},
{
scaleX: panX.interpolate({
inputRange: items.map((_item, i) => i),
outputRange: itemLayouts.map(l => l.width),
}),
},
],
}
const onLayout = () => {
const promises = []
for (let i = 0; i < items.length; i++) {
promises.push(
new Promise<Layout>(resolve => {
itemRefs[i].current?.measure(
(x: number, _y: number, width: number) => {
resolve({x, width})
},
)
}),
)
}
Promise.all(promises).then((layouts: Layout[]) => {
setItemLayouts(layouts)
})
}
const onPressItem = (index: number) => {
onSelect?.(index)
}
return (
<View style={[pal.view, styles.outer]} onLayout={onLayout}>
<Animated.View style={[styles.indicator, indicatorStyle]} />
{items.map((item, i) => {
const selected = i === selectedPage
return (
<TouchableWithoutFeedback key={i} onPress={() => onPressItem(i)}>
<View
style={
indicatorPosition === 'top' ? styles.itemTop : styles.itemBottom
}
ref={itemRefs[i]}>
<Text type="xl-bold" style={selected ? pal.text : pal.textLight}>
{item}
</Text>
</View>
</TouchableWithoutFeedback>
)
})}
</View>
)
}
const styles = StyleSheet.create({
outer: {
flexDirection: 'row',
paddingHorizontal: 14,
},
itemTop: {
paddingTop: 10,
paddingBottom: 10,
marginRight: 24,
},
itemBottom: {
paddingTop: 8,
paddingBottom: 12,
marginRight: 24,
},
indicator: {
position: 'absolute',
left: 0,
width: 1,
height: 3,
borderRadius: 4,
},
})
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