小程序怎么实现购物车抛物线动画

 wx.createAnimation 
css3 transition

<view class="box">
	<view><button bindtap="handleClick">点击</button></view><view animation="{{animationY}}" style="position:fixed;top:{{ballY}}px;" hidden="{{!showBall}}"><view class="ball" animation="{{animationX}}" style="position:fixed;left:{{ballX}}px;"></view></view>
</view>

// 设置延迟时间
    methods = {
		handleClick: (e) => {
			// x, y表示手指点击横纵坐标, 即小球的起始坐标
			let ballX = e.detail.x,
			    ballY = e.detail.y;
			this.isLoading = true;
			this.$apply();
			this.createAnimation(ballX, ballY);
		}
    }
	setDelayTime(sec) {
		return new Promise((resolve, reject) => {
			setTimeout(() => {resolve()}, sec)
		});
	}
	// 创建动画
	createAnimation(ballX, ballY) {
		let that = this,
		bottomX = that.$parent.globalData.windowWidth,
		bottomY = that.$parent.globalData.windowHeight-50,
		animationX = that.flyX(bottomX, ballX),      // 创建小球水平动画
		animationY = that.flyY(bottomY, ballY);			 // 创建小球垂直动画

		that.ballX = ballX;
		that.ballY = ballY;
		that.showBall = true;
		that.$apply();
		that.setDelayTime(100).then(() => {
			// 100ms延时,  确保小球已经显示
			that.animationX = animationX.export();
			that.animationY = animationY.export();
			that.$apply();
			// 400ms延时, 即小球的抛物线时长
			return that.setDelayTime(400);
		}).then(() => {
			that.animationX = this.flyX(0, 0, 0).export();
			that.animationY = this.flyY(0, 0, 0).export();
			that.showBall = false;
			that.isLoading = false;
			that.$apply();
		})
	}
	// 水平动画
	flyX(bottomX, ballX, duration) {
		let animation = wx.createAnimation({
			duration: duration || 400,
			timingFunction: 'linear',
		})
		animation.translateX(bottomX-ballX).step();
		return animation;
	}
	// 垂直动画
	flyY(bottomY, ballY, duration) {
		let animation = wx.createAnimation({
			duration: duration || 400,
			timingFunction: 'ease-in',
		})
		animation.translateY(bottomY-ballY).step();
		return animation;
	}