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huazhiyu/uni_modules/uview-ui/components/u-slider/mpother.js

114 lines
3.8 KiB

1 year ago
/**
* 使用普通的js方案实现slider
*/
export default {
watch: {
value(n) {
// 只有在非滑动状态时,才可以通过value更新滑块值,这里监听,是为了让用户触发
if (this.status === 'end') {
this.updateSliderPlacement(n, true)
}
}
},
mounted() {
this.init()
},
methods: {
init() {
this.getSliderRect()
},
// 获取slider尺寸
getSliderRect() {
// 获取滑块条的尺寸信息
setTimeout(() => {
this.$uGetRect('.u-slider').then((rect) => {
this.sliderRect = rect
this.updateSliderPlacement(this.value, true)
})
}, 10)
},
// 是否可以操作
canNotDo() {
return this.disabled
},
// 获取当前手势点的X轴位移值
getTouchX(e) {
return e.touches[0].clientX
},
formatStep(value) {
// 移动点占总长度的百分比
return Math.round(Math.max(this.min, Math.min(value, this.max)) / this.step) * this.step
},
// 发出事件
emitEvent(event, value) {
this.$emit(event, value || this.value)
},
// 标记当前手势的状态
setTouchStatus(status) {
this.status = status
},
onTouchStart(e) {
if (this.canNotDo()) {
return
}
// 标示当前的状态为开始触摸滑动
this.emitEvent('start')
this.setTouchStatus('start')
},
onTouchMove(e) {
if (this.canNotDo()) {
return
}
// 滑块的左边不一定跟屏幕左边接壤,所以需要减去最外层父元素的左边值
const x = this.getTouchX(e)
const { left, width } = this.sliderRect
const distanceX = x - left
// 获得移动距离对整个滑块的百分比值,此为带有多位小数的值,不能用此更新视图
// 否则造成通信阻塞,需要每改变一个step值时修改一次视图
const percent = (distanceX / width) * 100
this.setTouchStatus('moving')
this.updateSliderPlacement(percent, true, 'moving')
},
onTouchEnd() {
if (this.canNotDo()) {
return
}
this.emitEvent('end')
this.setTouchStatus('end')
},
// 设置滑点的位置
updateSliderPlacement(value, drag, event) {
// 去掉小数部分,同时也是对step步进的处理
const { width } = this.sliderRect
const percent = this.formatStep(value)
// 设置移动的值
const barStyle = {
width: `${percent / 100 * width}px`
}
// 移动期间无需过渡动画
if (drag === true) {
barStyle.transition = 'none'
} else {
// 非移动期间,删掉对过渡为空的声明,让css中的声明起效
delete barStyle.transition
}
// 修改value值
this.$emit('input', percent)
// 事件的名称
if (event) {
this.emitEvent(event, percent)
}
this.barStyle = barStyle
},
onClick(e) {
if (this.canNotDo()) {
return
}
// 直接点击滑块的情况,计算方式与onTouchMove方法相同
const { left, width } = this.sliderRect
const value = ((e.detail.x - left) / width) * 100
this.updateSliderPlacement(value, false, 'click')
}
}
}