使用typescript+react hook制作一个上拉、下拉刷新的DragView组件

·  阅读 51
使用typescript+react hook制作一个上拉、下拉刷新的DragView组件

不多逼逼直接上代码

DragView.tsx

import './drag-view.scss'
​
import { useState, TouchEvent, CSSProperties } from 'react'
​
interface DragViewProps {
  dragDown?: boolean
  dragUp?: boolean
  onDragDown?: (cb?: any) => void
  onDragUp?: (cb?: any) => void
}
​
// 触发上拉下拉刷新点
const MAX_OFFSET_Y = 35
​
// 存放上次touchmove时间
let prevTimeStamp = 0
​
// 节流时间
const TIME_STAMP_INTERVAL = 50
​
export const DragView = (props: DragViewProps) => {
  const { onDragDown, onDragUp } = props
​
  const [tip, setTip] = useState<string>()
  const [touchStart, setTouchStart] = useState<TouchEvent<HTMLDivElement>>()
  const [tipStyle, setTipStyle] = useState<CSSProperties>()
  const [state, setState] = useState<'can-down' | 'down' | 'none' | 'up' | 'can-up'>('none')
​
  const handleTouchStart = (e: TouchEvent<HTMLDivElement>) => {
    setTouchStart(e)
  }
​
  const handleTouchMove = (e: TouchEvent<HTMLDivElement>) => {
    // 节流
    if (e.timeStamp - prevTimeStamp < TIME_STAMP_INTERVAL) return
    prevTimeStamp = e.timeStamp
​
    // 除以3.5是为了产生一种拖拽感,其实有专门的算法可以模拟,懒得找了
    const offsetY = (e.changedTouches[0].clientY - touchStart!.changedTouches[0].clientY) / 3.5
    switch (true) {
      case offsetY < -MAX_OFFSET_Y:
        setTip('释放刷新')
        setState('can-up')
        break
      case offsetY < 0:
        setTip('上拉刷新')
        setState('up')
        break
      case offsetY < MAX_OFFSET_Y:
        setTip('下拉刷新')
        setState('down')
        break
      case offsetY >= MAX_OFFSET_Y:
        setTip('释放刷新')
        setState('can-down')
    }
​
    setTipStyle({ height: `${Math.abs(offsetY)}px` })
  }
​
  const handleTouchEnd = () => {
    const reset = () => {
      setTip('刷新成功')
      setTipStyle({ height: `0px`, transition: 'all 0.5s' })
      // 等待动画结束
      setTimeout(() => {setState('none')}, 500)
    }
 
​
    switch (state) {
      case 'can-down':
        setTipStyle({ height: `${MAX_OFFSET_Y}px`, transition: 'all 0.5s' })
        if (onDragDown) onDragDown(reset)
        else reset()
        break
      case 'can-up':
        if (onDragUp) onDragUp(reset)
        else reset()
        break
      default:
        setTipStyle({ height: '0px', transition: 'all 0.5s' })
    }
  }
​
  const tipCls = `drag-view__tip ${state}`
  return (
    <div className='drag-view'>
      <div className={tipCls} style={tipStyle}>
        <span>{tip}</span>
      </div>
      <div
        className='drag-view__content'
        onTouchStart={handleTouchStart}
        onTouchMove={handleTouchMove}
        onTouchEnd={handleTouchEnd}
      >
        1234
      </div>
    </div>
  )
}
​
复制代码

drag-view.scss

.drag-view {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
​
  &__tip {
    height: 0;
    font-size: 16px;
    color: rgba(0, 0, 0, 0.85);
    display: flex;
    justify-content: center;
    align-items: center;
​
    &.up,
    &.can-up {
      order: 1;
    }
​
    &.down,
    &.can-down {
      order: 0;
    }
  }
​
  &__content {
    width: 100%;
    height: 100%;
    transform: translateY(0);
    background-color: #ffffff;
    z-index: 9;
  }
}
​
复制代码

\

分类:
前端
标签: