微信小程序实现跑马灯效果
网上很多实现跑马灯的文章,但是很多发现都是不行的,之一就是文字宽度居然是通过字符数*文字size计算,明显是不准确的计算方式。我看了下,发现可以通过计算控件宽度来精确计算文字宽度,这样实现的跑马灯是比较完善的。
效果如下:
实现代码如下:
wxml:
<view class="rollCon"> <view class='box'> <view class='text'style='left:{{offsetLeft}}px' >{{text}}</view> </view> </view>
wxss:
.rollCon { position: fixed; top: 0; left: 0; width: 100%; height: 60rpx; z-index: 100; background: #fde8c7; font-size: 20rpx; line-height: 60rpx; } .box { width: 100%; position: relative; } .text { white-space: nowrap; position: absolute; top: 0; font-size: 24px; }
js:
Page({ /** * 页面的初始数据 */ data: { interval: null, text: '995年JavaScript诞生时如早一年', pace: 1.2, //滚动速度 interval: 20, //时间间隔 size: 24, //字体大小in px length: 0, //字体宽度 offsetLeft: 0, // windowWidth: 0, }, //根据viewId查询view的宽度 queryViewWidth: function(viewId) { //创建节点选择器 return new Promise(function(resolve) { var query = wx.createSelectorQuery(); var that = this; query.select('.' + viewId).boundingClientRect(function(rect) { resolve(rect.width); }).exec(); }); }, //停止跑马灯 stopMarquee: function() { var that = this; //清除旧的定时器 if (that.data != null) { clearInterval(that.interval); } }, //执行跑马灯动画 excuseAnimation: function() { var that = this; if (that.data.length > that.data.windowWidth) { //设置循环 let interval = setInterval(function() { if (that.data.offsetLeft <= 0) { if (that.data.offsetLeft >= -that.data.length) { that.setData({ offsetLeft: that.data.offsetLeft - that.data.pace, }) } else { that.setData({ offsetLeft: that.data.windowWidth, }) } } else { that.setData({ offsetLeft: that.data.offsetLeft - that.data.pace, }) } }, that.data.interval); } }, //开始跑马灯 startMarquee: function() { var that = this; that.stopMarquee(); //初始化数据 that.data.windowWidth = wx.getSystemInfoSync().windowWidth; that.queryViewWidth('text').then(function(resolve) { that.data.length = resolve; console.log(that.data.length + "/" + that.data.windowWidth); that.excuseAnimation(); }); } })
源码下载:跑马灯效果
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持我们。
赞 (0)