Vue购物车抛物线

css

    .shop{  
        position: fixed;  
        top: 300px;  
        left: 40px;  
     }  
   .ball{  
       position: fixed;  
       left: 32px;  
       bottom: 22px;  
       z-index: 200;  
       transition: all 0.4s cubic-bezier(0.49, -0.29, 0.75, 0.41); /*贝塞尔曲线*/  
    }  
   .inner{  
       width: 16px;  
       height: 16px;  
       border-radius: 50%;  
       background-color: rgb(0,160,220);  
       transition: all 0.4s linear;  
    }  
  .cart{  
      position: fixed;  
      bottom: 22px;  
      left: 32px;  
      width: 30px;  
      height: 30px;  
      background-color: rgb(0,160,220);  
      color: rgb(255,255,255);  
    }  

html

    <div id="app">  
        <ul class="shop">  
             <li v-for="item in items">  
                 <span>{{item.text}}</span>  
                 <span>{{item.price}}</span>  
                <button @click="additem">添加</button>  
             </li>  
      <div class="cart" style="">{{count}}</div>  
      <div class="ball-container"><!--小球-->  
      <div v-for="ball in balls">  
          <transition name="drop" @before-enter="beforeDrop" @enter="dropping" @after-enter="afterDrop">  
               <div class="ball" v-show="ball.show">  
                     <div class="inner inner-hook"></div>  
               </div>  
          </transition>  
     </div>  
   </div>  
</div>  

javascript

<script>  
     new Vue({  
          el:"#app",  
           data:{  
                count: 0,  
                items:[{  
                      text: "苹果",  
                      price: 15  
                      }, {  
                      text: "香蕉",  
                      price: 15  
                      }],  
           //小球 设为3个
                balls: [ { show: false },  
                         {  show: false },  
                         {  show: false },  ],  
               dropBalls:[],  
              },  
           methods:{  
              additem(event){  
                    this.drop(event.target);  
                    this.count ++;  
                 },  
              drop(el){ //抛物  
                    for(let i=0;i<this.balls.length;i++){  
                    let ball= this.balls[i];  
                    if(!ball.show){  
                          ball.el=el;  
                          this.dropBalls.push(ball);  
                          return;  
                       }  
                    }  
                },  
              beforeDrop(el) {/* 购物车小球动画实现 */  
                       let count = this.balls.length;  
                       while (count--) {  
                       let ball = this.balls[count];  
                       if (ball.show) {  
                             let rect = ball.el.getBoundingClientRect(); //元素相对于视口的位置  
                             let x = rect.left - 32;  
                             let y = -(window.innerHeight - rect.top - 22);  //获取y  
                             el.style.display = '';  
                             el.style.webkitTransform = 'translateY('+y+'px)';  //translateY  
                             el.style.transform = 'translateY('+y+'px)';  
                             let inner = el.getElementsByClassName('inner-hook')[0];  
                             inner.style.webkitTransform = 'translateX('+x+'px)';  
                             inner.style.transform = 'translateX('+x+'px)';  
                         }  
                   }  
            },  
            dropping(el, done) { /*重置小球数量  样式重置*/  
                          let rf = el.offsetHeight;  
                          el.style.webkitTransform = 'translate3d(0,0,0)';  
                          el.style.transform = 'translate3d(0,0,0)';  
                          let inner = el.getElementsByClassName('inner-hook')[0];  
                          inner.style.webkitTransform = 'translate3d(0,0,0)';  
                          inner.style.transform = 'translate3d(0,0,0)';  
                          el.addEventListener('transitionend', done);  
                      },  
                      afterDrop(el) { /*初始化小球*/  
                       let ball = this.dropBalls.shift();  
                             if (ball) {  
                                     ball.show=false;  
                                    el.style.display = 'none';  
                              }  
                     }  
             }  
      })  
</script>