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70 lines
1.3 KiB
70 lines
1.3 KiB
4 years ago
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<template>
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<view>
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<page-head :title="title"></page-head>
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<view class="uni-padding-wrap uni-common-mt">
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<view class="uni-title uni-common-mt">
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{{appear ? '小球出现' : '小球消失'}}
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</view>
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<scroll-view class="scroll-view" scroll-y>
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<view class="scroll-area">
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<text class="notice">向下滚动让小球出现</text>
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<view class="ball"></view>
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</view>
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</scroll-view>
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</view>
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</view>
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</template>
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<script>
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let observer = null;
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export default {
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data() {
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return {
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appear: false,
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title:'intersectionObserver'
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}
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},
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onReady() {
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observer = uni.createIntersectionObserver(this);
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observer.relativeTo('.scroll-view').observe('.ball', (res) => {
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if (res.intersectionRatio > 0 && !this.appear) {
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this.appear = true;
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} else if (!res.intersectionRatio > 0 && this.appear) {
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this.appear = false;
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}
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})
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},
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onUnload() {
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if (observer) {
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observer.disconnect()
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}
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}
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}
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</script>
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<style>
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.scroll-view {
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height: 400rpx;
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background: #fff;
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border: 1px solid #ccc;
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box-sizing: border-box;
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}
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.scroll-area {
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height: 1300rpx;
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display: flex;
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flex-direction: column;
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align-items: center;
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}
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.notice {
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margin-top: 150rpx;
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margin: 150rpx 0 400rpx 0;
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}
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.ball {
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width: 200rpx;
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height: 200rpx;
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background: #4cd964;
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border-radius: 50%;
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}
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</style>
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