现象描述：
stack组件下使用两个image组件堆叠，一个image组件通过动画样式设置透明度从1-0，隐藏起来，另一张显示出来，从而来实现图片切换，前一张图片会概率性的闪现然后消失。
问题代码如下：
<template>
<div class="page-wrapper">
<input type="button" class="button" onclick="onCallAnimationClick" value="Animation 动画" />
<stack style="width:400px;height:400px">
<image class="img" id="img1" src="{{imgUrl}}" oncomplete="imgcomplete"></image>
<image class="img" id="img2" if="{{ximg}}" src="{{preUrl}}" oncomplete="imgcomplete2" style="{{'opacity:' + preop + ';'}}"></image>
</stack>
</div>
</template>
<script>
export default {
data: {
imgsrc: ["https://ss1.bdstatic.com/70cFuXSh_Q1YnxGkpoWK1HF6hhy/it/u=1603365312,3218205429&fm=26&gp=0.jpg",
"https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fimg.aiimg.com%2Fuploads%2Fuserup%2F0909%2F2Z64022L38.jpg&refer=http%3A%2F%2Fimg.aiimg.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1611368024&t=879ac47e0bd97e413b5462946d9ae4ed",
"https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fpic3.16pic.com%2F00%2F01%2F11%2F16pic_111395_b.jpg&refer=http%3A%2F%2Fpic3.16pic.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1611368024&t=70c702a55248113dafa6e243dc253625",
"https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fa2.att.hudong.com%2F27%2F81%2F01200000194677136358818023076.jpg&refer=http%3A%2F%2Fa2.att.hudong.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1611368024&t=11199190c6ac8e3371f16d7568d40daa",
"https://ss1.bdstatic.com/70cFuXSh_Q1YnxGkpoWK1HF6hhy/it/u=1089874897,1268118658&fm=26&gp=0.jpg",
"https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fa3.att.hudong.com%2F92%2F04%2F01000000000000119090475560392.jpg&refer=http%3A%2F%2Fa3.att.hudong.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1611368024&t=3b33c5b006bcba88a24d03cfbca1ad20",
"https://ss0.baidu.com/7Po3dSag_xI4khGko9WTAnF6hhy/zhidao/pic/item/9c16fdfaaf51f3de9ba8ee1194eef01f3a2979a8.jpg",
"https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fa1.att.hudong.com%2F62%2F02%2F01300542526392139955025309984.jpg&refer=http%3A%2F%2Fa1.att.hudong.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1611368024&t=6500d50b1680d27bb60fe044e90ce41b",
],
imgUrl:'',
preUrl:'',
ximg:true,
preop:0,
i:0
},
onInit: function () {
this.imgUrl = this.imgsrc[0]
},
onCallAnimationClick() {
if(this.i > 6){
this.i = 0 ;
this.imgUrl = this.imgsrc[this.i]
}else{
this.i++
this.imgUrl = this.imgsrc[this.i]
}
console.log('imgcomplete=',this.i)
},
imgcomplete(){
console.log('imgcomplete 1')
this.preop = 1
var options = {
duration: 500,
easing: 'linear',
delay: 0,
fill: 'forwards',
iterations: 1
}
var frames = [{
opacity: 1
},
{
opacity: 0
}];
var animation = this.$element('img2').animate(frames, options);
animation.play();
var self = this
animation.onfinish = function () {
console.log("imgcomplete animation onfinish");
self.ximg = false
self.preop = 0
setTimeout(() => {
self.ximg = true
self.preUrl = self.$element("img1").attr.src
}, 30);
}
},
imgcomplete2() {
console.log('imgcomplete 2')
setTimeout(() => {
this.preop = 1
}, 50);
},
}
</script>
<style>
.page-wrapper {
flex-direction: column;
justify-content: center;
align-items: center;
}
.img{
width:100%;
height:100%;
}
.button {
color: #20a0ff;
background-color: #ffffff;
padding: 10px 20px;
border: 1px solid #20a0ff;
border-radius: 40px;
}
</style>
问题分析：
上述代码用两个image组件实现了图片切换时淡入淡出的动画效果，主要是通过透明度实现的。第二个image的css中设置了透明度，但是imgcomplete()方法中又对该image组件做了透明度动画，透明度值从1到0，同时代码中又将css中绑定的透明度变量preop设置为1。
当动画方法完成时间先于css，就会出现这个情况。
解决方法：
template中第二个image组件的style="{{'opacity:' + preop + ';'}}"去掉，改为通过动画样式来调用，从0-1变化。
修改代码如下：
<template>
<div class="page-wrapper">
<input type="button" class="button" onclick="onCallAnimationClick" value="Animation 动画" />
<stack style="width:400px;height:400px">
<image class="img" id="img1" src="{{imgUrl}}" oncomplete="imgcomplete"></image>
<image class="img" id="img2" if="{{ximg}}" src="{{preUrl}}" oncomplete="imgcomplete2" ></image>
</stack>
</div>
</template>
<script>
export default {
data: {
imgsrc: ["https://ss1.bdstatic.com/70cFuXSh_Q1YnxGkpoWK1HF6hhy/it/u=1603365312,3218205429&fm=26&gp=0.jpg",
"https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fimg.aiimg.com%2Fuploads%2Fuserup%2F0909%2F2Z64022L38.jpg&refer=http%3A%2F%2Fimg.aiimg.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1611368024&t=879ac47e0bd97e413b5462946d9ae4ed",
"https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fpic3.16pic.com%2F00%2F01%2F11%2F16pic_111395_b.jpg&refer=http%3A%2F%2Fpic3.16pic.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1611368024&t=70c702a55248113dafa6e243dc253625",
"https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fa2.att.hudong.com%2F27%2F81%2F01200000194677136358818023076.jpg&refer=http%3A%2F%2Fa2.att.hudong.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1611368024&t=11199190c6ac8e3371f16d7568d40daa",
"https://ss1.bdstatic.com/70cFuXSh_Q1YnxGkpoWK1HF6hhy/it/u=1089874897,1268118658&fm=26&gp=0.jpg",
"https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fa3.att.hudong.com%2F92%2F04%2F01000000000000119090475560392.jpg&refer=http%3A%2F%2Fa3.att.hudong.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1611368024&t=3b33c5b006bcba88a24d03cfbca1ad20",
"https://ss0.baidu.com/7Po3dSag_xI4khGko9WTAnF6hhy/zhidao/pic/item/9c16fdfaaf51f3de9ba8ee1194eef01f3a2979a8.jpg",
"https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fa1.att.hudong.com%2F62%2F02%2F01300542526392139955025309984.jpg&refer=http%3A%2F%2Fa1.att.hudong.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1611368024&t=6500d50b1680d27bb60fe044e90ce41b",
],
imgUrl:'',
preUrl:'',
ximg:true,
preop:0,
i:0
},
onInit: function () {
this.imgUrl = this.imgsrc[0]
},
... //省略
imgcomplete2() {
console.log('imgcomplete 2')
var options = {
duration: 10,
easing: 'linear',
delay: 0,
fill: 'forwards',
iterations: 1
}
var frames = [{
opacity: 0
},
{
opacity: 1
}];
var animation = this.$element('img2').animate(frames, options);
animation.play();
},
}
</script>
欲了解更多详情，请参见：
快应用动画：
developer.huawei.com/consumer/cn…
快应用通用样式：
developer.huawei.com/consumer/cn…
原文链接：developer.huawei.com/consumer/cn…
原作者：Mayism
