往返运动（左>右>左>右）

wxml

js

Page({
  data:{
        animation:''
  },
   onReady: function () {  
      var circleCount = 0;  
      // 心跳的外框动画  
      this.animationMiddleHeaderItem = wx.createAnimation({  
        duration:1000,    // 以毫秒为单位  
        timingFunction: 'linear',  
        delay: 100,  
        transformOrigin: '50% 50%'
      });  
        
      setInterval(function() {  
        if (circleCount % 2 == 0) {  
          this.animationMiddleHeaderItem.translate(100).step();  
        } else {  
//        this.animationMiddleHeaderItem.translate(0).step();  
        }  
          
        this.setData({  
          animationMiddleHeaderItem: this.animationMiddleHeaderItem.export()  
        });  
          
        circleCount++;  
        if (circleCount == 1000) {  
          circleCount = 0;  
        }  
      }.bind(this), 1000);  
        
    }

})