diff --git a/src/swipe-item/index.js b/src/swipe-item/index.js index d0e7ba973..6e01fed0e 100644 --- a/src/swipe-item/index.js +++ b/src/swipe-item/index.js @@ -9,19 +9,22 @@ export default createComponent({ data() { return { offset: 0, + mounted: false, }; }, + mounted() { + this.$nextTick(() => { + this.mounted = true; + }); + }, + computed: { style() { const style = {}; - const { vertical, computedWidth, computedHeight } = this.parent; + const { size, vertical } = this.parent; - if (vertical) { - style.height = `${computedHeight}px`; - } else { - style.width = `${computedWidth}px`; - } + style[vertical ? 'height' : 'width'] = `${size}px`; if (this.offset) { style.transform = `translate${vertical ? 'Y' : 'X'}(${this.offset}px)`; @@ -29,12 +32,32 @@ export default createComponent({ return style; }, + + shouldRender() { + const { index, parent, mounted } = this; + + if (!parent.lazyRender) { + return true; + } + + // wait for all item to mount, so we can get the exact count + if (!mounted) { + return false; + } + + const active = parent.activeIndicator; + const maxActive = parent.count - 1; + const prevActive = active === 0 ? maxActive : active - 1; + const nextActive = active === maxActive ? 0 : active + 1; + + return index === active || index === prevActive || index === nextActive; + }, }, render() { return (
- {this.slots()} + {this.shouldRender && this.slots()}
); }, diff --git a/src/swipe-item/index.less b/src/swipe-item/index.less index 0fdb679e8..3755c3296 100644 --- a/src/swipe-item/index.less +++ b/src/swipe-item/index.less @@ -1,6 +1,7 @@ @import '../style/var'; .van-swipe-item { + position: relative; flex-shrink: 0; width: 100%; height: 100%; diff --git a/src/swipe/README.md b/src/swipe/README.md index 2084f2d7a..1785f78cc 100644 --- a/src/swipe/README.md +++ b/src/swipe/README.md @@ -128,20 +128,14 @@ export default { ``` @@ -176,6 +170,7 @@ export default { | vertical | Whether to be vertical Scrolling | *boolean* | `false` | | touchable | Whether to allow swipe by touch gesture | *boolean* | `true` | | stop-propagation `v2.1.0` | Whether to stop touchmove event propagation | *boolean* | `false` | +| lazy-render `v2.6.0` | Whether to enable lazy render | *boolean* | `false` | | indicator-color | Indicator color | *string* | `#1989fa` | ### Swipe Events diff --git a/src/swipe/README.zh-CN.md b/src/swipe/README.zh-CN.md index 3a7d3d5f0..a933f516c 100644 --- a/src/swipe/README.zh-CN.md +++ b/src/swipe/README.zh-CN.md @@ -134,20 +134,14 @@ export default { ``` @@ -182,6 +176,7 @@ export default { | vertical | 是否为纵向滚动 | *boolean* | `false` | | touchable | 是否可以通过手势滑动 | *boolean* | `true` | | stop-propagation `v2.2.13` | 是否阻止滑动事件冒泡 | *boolean* | `true` | +| lazy-render `v2.6.0` | 是否延迟渲染未展示的轮播 | *boolean* | `false` | | indicator-color | 指示器颜色 | *string* | `#1989fa` | ### Swipe Events diff --git a/src/swipe/index.js b/src/swipe/index.js index d754e4a58..6a8cc2847 100644 --- a/src/swipe/index.js +++ b/src/swipe/index.js @@ -33,6 +33,7 @@ export default createComponent({ height: [Number, String], autoplay: [Number, String], vertical: Boolean, + lazyRender: Boolean, indicatorColor: String, loop: { type: Boolean, @@ -62,13 +63,13 @@ export default createComponent({ data() { return { - computedWidth: 0, - computedHeight: 0, offset: 0, active: 0, deltaX: 0, deltaY: 0, swiping: false, + computedWidth: 0, + computedHeight: 0, }; }, diff --git a/src/swipe/test/index.spec.js b/src/swipe/test/index.spec.js index 2fe219e33..acb40688f 100644 --- a/src/swipe/test/index.spec.js +++ b/src/swipe/test/index.spec.js @@ -171,3 +171,47 @@ test('should pause auto play when page hidden', async () => { expect(change).toHaveBeenCalledTimes(0); }); + +test('lazy-render prop', async () => { + const wrapper = mount({ + template: ` + + 1 + 2 + 3 + 4 + + `, + data() { + return { + active: 0, + }; + }, + }); + + await later(); + const items = wrapper.findAll('.van-swipe-item'); + + expect(items.at(0).contains('span')).toBeTruthy(); + expect(items.at(1).contains('span')).toBeTruthy(); + expect(items.at(2).contains('span')).toBeFalsy(); + expect(items.at(3).contains('span')).toBeTruthy(); + + wrapper.setData({ active: 1 }); + expect(items.at(0).contains('span')).toBeTruthy(); + expect(items.at(1).contains('span')).toBeTruthy(); + expect(items.at(2).contains('span')).toBeTruthy(); + expect(items.at(3).contains('span')).toBeFalsy(); + + wrapper.setData({ active: 2 }); + expect(items.at(0).contains('span')).toBeFalsy(); + expect(items.at(1).contains('span')).toBeTruthy(); + expect(items.at(2).contains('span')).toBeTruthy(); + expect(items.at(3).contains('span')).toBeTruthy(); + + wrapper.setData({ active: 3 }); + expect(items.at(0).contains('span')).toBeTruthy(); + expect(items.at(1).contains('span')).toBeFalsy(); + expect(items.at(2).contains('span')).toBeTruthy(); + expect(items.at(3).contains('span')).toBeTruthy(); +});