本文实例为大家分享了微信小程序实现数字滚动效果的具体代码，供大家参考，具体内容如下
效果图
1、为了实现数字的无限滚动效果，每个数字框的内部，其实包含了两组0~9的view，每个View的高度都一样
2、数字框内使用绝对定位，通过调整top位置，显示出指定的数字
3、使用transtion动画，top发生变化时就会滚动，然后通过指定动画的delay、duration，使数字之间延时动画
js文件
// components/scroll-number/index.js
Component({
externalClasses: ['container-class', 'item-class', 'dot-class'],
properties: {
value: {
type: String,
value: ''
},
/** 一次滚动耗时 单位ms */
duration: {
type: Number,
value: 1600
},
/** 每个数字之间的延迟滚动 */
delay: {
type: Number,
value: 200
}
},
data: {
valArr: [],
aniArr: [], // 动画列表，和valArr对应
numArr: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], // 所有数字
itemHeight: 0 // 数字项的高度
},
observers: {
value: function (newVal) {
// 监听value变化，格式化为valArr
let valArr = []
if (newVal) {
valArr = newVal.split('').map(o => {
return { val: o, isNaN: isNaN(o)}
})
}
this.setData({
valArr: valArr
})
this.getNumberHeight()
}
},
methods: {
/** 计算数字高度 */
getNumberHeight() {
if (this.data.itemHeight > 0) {
this.startScrollAni()
return
}
const query = this.createSelectorQuery()
query.select('.number-item').boundingClientRect()
query.exec((res) => {
this.setData({
itemHeight: res[0].height
})
this.startScrollAni()
})
},
/** 开始滚动动画 */
startScrollAni() {
if (this.data.itemHeight <= 0) return
const aniArr = []
this.data.valArr.forEach((item, index) => {
if(!item.isNaN) {
aniArr.push(`transition-delay: ${this.data.delay * index}ms; top: ${-this.data.itemHeight * (this.data.numArr[parseInt(item.val)] + 10)}px;`)
} else {
aniArr.push(null)
}
})
this.setData({
aniArr: aniArr
})
}
}
})
wxml文件
<!--components/scroll-number/index.wxml-->
<view class="scroll-number container-class">
<block wx:for="{{valArr}}" wx:key="index">
<view wx:if="{{item.isNaN}}" class="scroll-number-item number-dot dot-class">{{item.val}}</view>
<view wx:else class="scroll-number-item number-item item-class">
<view class="scroll-ani" style="transition-duration: {{duration}}ms; {{aniArr[index]}}">
<view wx:for="{{numArr}}" wx:for-item="num" wx:for-index="idx" wx:key="idx" class="num{{num}}">{{num}}</view>
<view wx:for="{{numArr}}" wx:for-item="num" wx:for-index="idx" wx:key="idx" class="num{{num}}">{{num}}</view>
</view>
</view>
</block>
</view>
wxss文件
/* components/scroll-number/index.wxss */
.scroll-number {
display: flex;
align-items: flex-end;
}
.scroll-number-item {
color: #0079FE;
font-size: 48rpx;
font-weight: bold;
margin: 0 24rpx;
font-family: Microsoft YaHei;
}
.number-item {
background-color: rgba(0, 121, 254, 0.2);
border-radius: 8rpx;
width: 56rpx;
height: 72rpx;
line-height: 72rpx;
overflow: hidden;
text-align: center;
position: relative;
}
.number-dot {
margin: 0 12rpx;
}
.scroll-ani {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
transition: all 2s ease-in-out 0s;
}
