| /** | |
|  * 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') | |
|         } | |
|     } | |
| }
 |