实现效果

<view>
	<scroll-view class="scroll-view_H" scroll-x="true" @scroll="scroll" scroll-left="0"
					:scroll-with-animation="true">
	     <view id="demo1" class="scroll-view-item_H uni-bg-red">A</view>
		 <view id="demo2" class="scroll-view-item_H uni-bg-green">B</view>
		<view id="demo3" class="scroll-view-item_H uni-bg-blue">C</view>
	</scroll-view>
</view>

<view class="uni-common-pb">
	<image :src="currentIndex == 0?selectDot:normalDot"></image>
	<image :src="currentIndex == 1?selectDot:normalDot"></image>
	<image :src="currentIndex == 2?selectDot:normalDot"></image>
</view>

normalDot: '../../static/cc-dot-o.png',
selectDot: '../../static/cc-dot.png',
currentIndex: 0

scroll: function(e) {
				// console.log(e.target.scrollLeft)
				this.old.scrollTop = e.detail.scrollTop
				// 判断滑动的位置 具体情况决定范围
				if(e.target.scrollLeft < 140) {
					this.currentIndex = 0;
				}
				 if(e.target.scrollLeft >= 140 && e.target.scrollLeft <= 440) {
					 this.currentIndex = 1;
				 }
				 if(e.target.scrollLeft > 440) {
					 this.currentIndex = 2;
				 }
				 
				 console.log(this.currentIndex)
			},

	.scroll-view_H {
		white-space: nowrap;
		width: 100%;
	}
	.scroll-view-item_H {
		display: inline-block;
		width: 600rpx;
		height: 350rpx;
		line-height: 350rpx;
		text-align: center;
		font-size: 36rpx;
		margin-right: 50rpx;
		border-radius: 20rpx;
	}
	.scroll-view-item_H:first-child {
		margin-left: 50rpx;
	}
	.uni-bg-red {
		background-color: red
	}

	.uni-bg-green {
		background-color: green
	}

	.uni-bg-blue {
		background-color: blue;
	}
	/* 指示器相关 */
	.uni-common-pb {
		width: 100%;
		text-align: center;
		margin-top: 50rpx;
	}

	.uni-common-pb image {
		width: 80rpx;
		height: 80rpx;
	}