IntersectionObserver.disconnect

与页面显示区域的相交区域并不准确代表用户可见的区域,因为参与计算的区域是“布局区域”,布局区域可能会在绘制时被其他节点裁剪隐藏(如遇祖先节点中 overflow 样式为 hidden 的节点)或遮盖(如遇 fixed 定位的节点)。

解释:停止监听,回调函数将不再触发。

# 方法参数

# 示例

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# 图片示例

# 代码示例

    <view class="wrap">
        <scroll-view class="scroll-view" scroll-y>
            <view class="scroll-area" style="{{appear ? 'background: #ccc' : ''}}">
                <text class="notice">向下滚动让小球出现</text>
                <!-- 占位元素 -->
                <view class="filling"></view> 
                <!-- 小球 -->
                <view class="ball"></view>
            </view>
        </scroll-view>
        <view class="list-area border-bottom">
            <view class="list-item-key-4">top:</view>
            <view class="list-item-value">{{intersectionRect.top}}</view>
        </view>
        <view class="list-area border-bottom">
            <view class="list-item-key-4">right:</view>
            <view class="list-item-value">{{intersectionRect.right}}</view>
        </view>
        <view class="list-area border-bottom">
            <view class="list-item-key-4">bottom:</view>
            <view class="list-item-value">{{intersectionRect.bottom}}</view>
        </view>
        <view class="list-area border-bottom">
            <view class="list-item-key-4">left:</view>
            <view class="list-item-value">{{intersectionRect.left}}</view>
        </view>
        <view class="list-area border-bottom">
            <view class="list-item-key-4">width</view>
            <view class="list-item-value">{{intersectionRect.width}}</view>
        </view>
        <view class="list-area border-bottom">
            <view class="list-item-key-4">height</view>
            <view class="list-item-value">{{intersectionRect.height}}</view>
        </view>
        <button type="primary" bindtap="disconnect">停止监听</button>
    </view>
    
    
    Page({
        data: {
            intersectionRect: ''
        },
        onReady() {
            this.intersectionObserver = swan.createIntersectionObserver(this);
            this.intersectionObserver
                .relativeTo('.scroll-view')
                .observe('.ball', res => {
                    this.setData('intersectionRect', res.intersectionRect);
                    console.log(res.intersectionRect.left); // 相交区域的左边界坐标
                    console.log(res.intersectionRect.right); // 相交区域的右边界坐标
                    console.log(res.intersectionRect.top); // 相交区域的上边界坐标
                    console.log(res.intersectionRect.bottom); // 相交区域的下边界坐标
                    console.log(res.intersectionRect.width); // 相交区域的宽度
                    console.log(res.intersectionRect.height); // 相交区域的高度
            });
        },
        disconnect() {
            this.intersectionObserver && this.intersectionObserver.disconnect();
        }
    });