touch-events.uvue

<template>
  <scroll-view style="flex: 1">
    <page-head title="拖拽图标测试相关事件"></page-head>
    <view class="container">
      <view class="view-box" @touchstart="onViewTouchStart">
        <image class="icon" id="icon" src="../image/logo.png" @touchstart="onTouchStart" @touchcancel="onTouchCancel"
          @touchmove="onTouchMove" @touchend="onTouchEnd"></image>
      </view>

    </view>
    <view v-if="touchEvent !== null">
      <text class="title1">touches: </text>
      <template v-for="(touch, index) in touchEvent!.touches" :key="index">
        <text class="title2">touch[{{ index }}]:</text>
        <text>identifier: {{touch.identifier}}</text>
        <text>pageX: {{ touch.pageX }}, pageY: {{ touch.pageY }}</text>
        <text>clientX: {{ touch.clientX }}, clientY: {{ touch.clientY }}</text>
        <text>screenX: {{ touch.screenX }}, screenY: {{ touch.screenY }}</text>
      </template>
    </view>
  </scroll-view>
</template>

<script>
  export default {
    data() {
      return {
        move: false,
        posX: 0,
        posY: 0,
        lastX: 0,
        lastY: 0,
        touchEvent: null as TouchEvent | null,
        icon: null as UniElement | null,
        touchTargets: "",
        touchTargetsCount: 0,
        iconRect : null as DOMRect | null
      }
    },
    onReady() {
      this.icon = uni.getElementById("icon")
      // #ifdef APP-IOS
      this.iconRect = this.icon?.getBoundingClientRect()
      // 加上导航栏及状态栏高度
      this.iconRect.y += uni.getSystemInfoSync().safeArea.top + 44
      // #endif
    },
    methods: {
      onViewTouchStart(e : TouchEvent) {
        this.touchTargets += e.target!.tagName + e.currentTarget!.tagName
        this.touchTargetsCount++
        // console.log(this.touchTargets, this.touchTargetsCount)
      },
      onTouchStart(e : TouchEvent) {
        this.touchTargetsCount++
        this.touchTargets += e.target!.tagName + e.currentTarget!.tagName

        this.touchEvent = e
        if (!this.move) {
          this.move = true
          this.posX = e.touches[0].screenX
          this.posY = e.touches[0].screenY
        }
      },
      onTouchMove(e : TouchEvent) {
        e.preventDefault()
        this.touchEvent = e
        let p = e.touches[0]
        if (p.screenX == this.lastX && p.screenY == this.lastY) {
          return
        }
        let x = p.screenX - this.posX
        let y = p.screenY - this.posY
        this.lastX = p.screenX
        this.lastY = p.screenY
        this.icon?.style?.setProperty('transform', 'translate(' + x + 'px,' + y + 'px)')
      },
      onTouchEnd(e : TouchEvent) {
        if (e.touches.length == 0) {
          this.resetIcon()
          this.touchEvent = null
        }
      },
      onTouchCancel(_ : TouchEvent) {
        this.resetIcon()
        this.touchEvent = null
      },
      resetIcon() {
        this.move = false;
        this.posX = 0;
        this.posY = 0;
        this.icon?.style?.setProperty('transform', 'translate(0px,0px)')
      }
    }
  }
</script>

<style>
  .container {
    width: 100%;
    flex-direction: column;
    align-items: center;
  }

  .view-box {
    width: 300px;
    height: 300px;
    align-items: center;
    justify-content: center;
    border-style: solid;
  }

  .icon {
    width: 100px;
    height: 100px;
  }

  .msg-text {
    margin-bottom: 100px;
  }

  .title1 {
    margin-top: 10px;
    font-size: 18px;
  }

  .title2 {
    margin-top: 5px;
    font-size: 16px;
  }
</style>