| /** | |
|  * 使用wxs方案实现slider | |
|  * 兼容微信,QQ,H5,Vue版的安卓和iOS | |
|  */ | |
| /** | |
|  * 开始滑动操作 | |
|  * @param {Object} e | |
|  * @param {Object} ownerInstance | |
|  */ | |
| function onTouchMove(e, ownerInstance) { | |
| 	// wxs事件对象下有一个instance属性,表示当前触发此事件的组件的实例,通过该实例,可以获取相关的dataset,设置样式等信息 | |
| 	// https://developers.weixin.qq.com/miniprogram/dev/framework/view/interactive-animation.html | |
| 	var instance = e.instance; | |
| 	// getState()为一个对象,挂载在instance上,类似组件的data一样,可以存放一些变量,供以后的触发事件中使用 | |
| 	var state = instance.getState() | |
| 
 | |
| 	// 滑块组件的整体尺寸信息 | |
| 	var mp = state.mp | |
| 	if(mp.disabled) { | |
| 		return | |
| 	} | |
| 	 | |
| 	var distanceX = getTouchX(e) - mp.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,step大于1时,不能用此更新视图 | |
| 	var percent = (distanceX / mp.width) * 100 | |
| 
 | |
| 	updateSliderPlacement(instance, ownerInstance, percent, 'moving') | |
| 	 | |
| 	// 阻止页面滚动,可以保证在滑动过程中,不让页面可以上下滚动,造成不好的体验 | |
| 	e.stopPropagation && e.stopPropagation()  | |
| 	e.preventDefault && e.preventDefault() | |
| } | |
| 
 | |
| function onClick(e, ownerInstance) { | |
| 	var instance = e.instance | |
| 	var state = instance.getState() | |
| 	var mp = state.mp | |
| 	if(mp.disabled) { | |
| 		return | |
| 	} | |
| 	 | |
| 	// 直接点击滑块的情况,计算方式与onTouchMove方法相同 | |
| 	var value = ((e.detail.x - mp.left) / mp.width) * 100 | |
| 	updateSliderPlacement(instance, ownerInstance, value, 'click') | |
| } | |
| 
 | |
| function sizeReady(newValue, oldValue, ownerInstance, instance) { | |
| 	// 页面初始化时候,也会触发此方法,传递的值为空,这里不执行往后的逻辑 | |
| 	if(!newValue || newValue.disabled) { | |
| 		return  | |
| 	} | |
| 	var state = instance.getState() | |
| 	state.mp = newValue | |
| 	updateSliderPlacement(instance, ownerInstance, newValue.value) | |
| } | |
| 
 | |
| // 设置滑点的位置 | |
| function updateSliderPlacement(instance, ownerInstance, value, event) { | |
| 	var state = instance.getState() | |
| 	var mp = state.mp | |
| 	if(mp.disabled) { | |
| 		return | |
| 	} | |
| 
 | |
| 	var percent = 0 | |
| 	if (mp.step > 1) { | |
| 		// 如果step步进大于1,需要跳步,所以需要使用Math.round进行取整 | |
| 		percent = Math.round(Math.max(mp.min, Math.min(value, mp.max)) / mp.step) * mp.step | |
| 	} else { | |
| 		// 当step=1时,无需跳步,充分利用wxs性能,滑块实时跟随手势,达到丝滑的效果 | |
| 		percent = Math.max(mp.min, Math.min(value, mp.max)) | |
| 	} | |
| 	// 返回组件的实例 | |
| 	var gapInstance = ownerInstance.selectComponent('.u-slider__gap') | |
| 	// 在移动期间,不允许transition动画,否则会造成卡顿 | |
| 	gapInstance[event === 'click' ? 'addClass' : 'removeClass']('u-slider__gap--ani') | |
| 	// 调用逻辑层的方法,修改v-model绑定的值 | |
| 	ownerInstance.callMethod('updateValue', Math.round(percent)) | |
| 	if(event) { | |
| 		ownerInstance.callMethod('emitEvent', { | |
| 			event: event, | |
| 			value: Math.round(percent) | |
| 		}) | |
| 	} | |
| 	 | |
| 	// 设置移动的值 | |
| 	gapInstance.requestAnimationFrame(function() { | |
| 		gapInstance.setStyle({ | |
| 			width: percent / 100 * mp.width + 'px', | |
| 		}) | |
| 	}) | |
| } | |
| 
 | |
| // 开始滑动 | |
| function onTouchStart(e, ownerInstance) { | |
| 	ownerInstance.callMethod('emitEvent', { | |
| 		event: 'start',  | |
| 		value: null | |
| 	}) | |
| } | |
| 
 | |
| // 停止滑动 | |
| function onTouchEnd(e, ownerInstance) { | |
| 	ownerInstance.callMethod('emitEvent', { | |
| 		event: 'end',  | |
| 		value: null | |
| 	}) | |
| } | |
| 
 | |
| // 获取当前手势点的X轴位移值 | |
| function getTouchX(e) { | |
| 	return e.touches[0].clientX | |
| } | |
| 
 | |
| module.exports = { | |
| 	onTouchStart: onTouchStart, | |
| 	onTouchMove: onTouchMove, | |
| 	onTouchEnd: onTouchEnd, | |
| 	sizeReady: sizeReady, | |
| 	onClick: onClick | |
| }
 |