微信小程序仿QQ头像轮播效果

1、效果图

2、效果流程分析

1、第1个头像大小从1到0缩小的同时，第2个头像左移

2、上面动画结束后，延迟50ms，第3个头像从0到1放大

3、把头像列表顺序前移一位，并重置轮播状态，以此达到一个循环。然后继续第一个步骤

3、源码

组件使用

<AvatarsBanner avatars="{{avatars}}" />
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index.wxml

<view
  class="avatarList"
  style="width:{{itemWidth*3-overlapWidth*2}}rpx;"
>
  <!-- 备注：微信小程序经测试，即使不渲染的元素也要添加到节点上，否则第3个的放大动画不会展示 -->
  <image
    src="{{item}}"
    animation="{{index===0?firstAnimation:(index===1?secondAnimation:(index===2?lastAnimation:''))}}"
    wx:for="{{avatars}}"
    wx:key="index"
    style="left: {{(itemWidth-overlapWidth)*index}}rpx; z-index: {{avatars.length-index}};width:{{itemWidth}}rpx;height:{{itemWidth}}rpx;"
    class="avatarImage {{index>2 && 'hidden'}}"
  />
</view>
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index.js

const animalTime = 200; // 动画时间
const intervalTime = 1000; // 定时器频率

Component({
  properties: {
    // 头像列表
    avatars: {
      type: Array,
      value: [],
      observer(newVale) {
        this.interval && clearInterval(this.interval);
        this.startAnimation();
      },
    },
    style: {
      type: String,
      value: '',
    },
    // 图片宽度：rpx
    itemWidth: {
      type: Number,
      value: 36,
    },
    // 重叠部分宽度：rpx
    overlapWidth: {
      type: Number,
      value: 10,
    },
  },
  data: {},
  methods: {
    startAnimation() {
      const { avatars } = this.data;
      const { itemWidth, overlapWidth } = this.properties;
      if (avatars.length < 3) {
        return;
      }
      // 创建animation对象
      this.firstAnimation = wx.createAnimation();
      this.secondAnimation = wx.createAnimation();
      this.lastAnimation = wx.createAnimation();

      this.interval = setInterval(() => {
        // num1缩放动画
        this.firstAnimation.scale(0).step({ duration: animalTime });
        this.setData({
          firstAnimation: this.firstAnimation.export(),
        });

        // num2、num3平移动画(除以2是rpx转px)
        const offsetX = (overlapWidth - itemWidth)/2;
        this.secondAnimation.translate(offsetX, 0).step({ duration: animalTime });
        this.lastAnimation.translate(offsetX, 0).step({ duration: animalTime });
        this.setData({
          secondAnimation: this.secondAnimation.export(),
          lastAnimation: this.lastAnimation.export(),
        });

        // num3放大动画（animalTime + 50：表示前面两个动画结束，并且setData数据更新）
        setTimeout(() => {
          this.lastAnimation.scale(1).step({ duration: animalTime });
          this.setData({
            lastAnimation: this.lastAnimation.export(),
          });
        }, animalTime + 50);

        // 还原动画 (等待缩小动画完成后再切换头像)
        setTimeout(() => {
          this.firstAnimation.scale(1).step({
            duration: 0,
          });
          this.secondAnimation.translate(0, 0).step({
            duration: 0,
          });
          this.lastAnimation.translate(0, 0).scale(0).step({
            duration: 0,
          });
          this.setData({
            avatars: avatars.slice(1).concat(avatars[0]),
            lastAnimation: this.lastAnimation.export(),
            firstAnimation: this.firstAnimation.export(),
            secondAnimation: this.secondAnimation.export(),
          });
        }, animalTime);
      }, intervalTime);
    },
  },
});
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index.wxss

.avatarList {
  display: flex;
  flex-direction: row;
  position: relative;
  height: 100%;
}

.avatarImage {
  position: absolute;
  border: 1rpx solid #ffffff;
  border-radius: 50%;

  /* 占位图 */
  background-image: url('https://xm-1301527776.cos.ap-shanghai.myqcloud.com/images/miniprogram/channel/Post/ic_default_header.png');
  background-repeat: no-repeat;
  background-position: center;
  background-color: #f6f6f6;
  background-size: cover;
}

.hidden {
  display: none;
}
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