tn-lazy-load.vue 16 KB

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  1. <template>
  2. <view class="tn-lazy-load-class tn-lazy-load">
  3. <view
  4. class="tn-lazy-load__item"
  5. :class="[`tn-lazy-load__item--${elIndex}`]"
  6. :style="[lazyLoadItemStyle]"
  7. >
  8. <view class="tn-lazy-load__item__content">
  9. <image
  10. v-if="!error"
  11. class="tn-lazy-load__item__image"
  12. :style="[imageStyle]"
  13. :src="show ? image : loadingImg"
  14. :mode="imgMode"
  15. @load="handleImgLoaded"
  16. @error="handleImgError"
  17. @tap="handleImgClick"
  18. ></image>
  19. <image
  20. v-else
  21. class="tn-lazy-load__item__image tn-lazy-load__item__image--error"
  22. :style="[imageStyle]"
  23. :src="errorImg"
  24. :mode="imgMode"
  25. @load="handleErrorImgLoaded"
  26. @tap="handleImgClick"
  27. ></image>
  28. </view>
  29. </view>
  30. </view>
  31. </template>
  32. <script>
  33. export default {
  34. name: 'tn-lazy-load',
  35. props: {
  36. // 组件标识
  37. index: {
  38. type: [String, Number],
  39. default: ''
  40. },
  41. // 待显示的图片地址
  42. image: {
  43. type: String,
  44. default: ''
  45. },
  46. // 图片裁剪模式
  47. imgMode: {
  48. type: String,
  49. default: 'scaleToFill'
  50. },
  51. // 占位图片路径
  52. loadingImg: {
  53. type: String,
  54. // default: 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAGQCAMAAAC3Ycb+AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAyJpVFh0WE1MOmNvbS5hZG9iZS54bXAAAAAAADw/eHBhY2tldCBiZWdpbj0i77u/IiBpZD0iVzVNME1wQ2VoaUh6cmVTek5UY3prYzlkIj8+IDx4OnhtcG1ldGEgeG1sbnM6eD0iYWRvYmU6bnM6bWV0YS8iIHg6eG1wdGs9IkFkb2JlIFhNUCBDb3JlIDUuMy1jMDExIDY2LjE0NTY2MSwgMjAxMi8wMi8wNi0xNDo1NjoyNyAgICAgICAgIj4gPHJkZjpSREYgeG1sbnM6cmRmPSJodHRwOi8vd3d3LnczLm9yZy8xOTk5LzAyLzIyLXJkZi1zeW50YXgtbnMjIj4gPHJkZjpEZXNjcmlwdGlvbiByZGY6YWJvdXQ9IiIgeG1sbnM6eG1wPSJodHRwOi8vbnMuYWRvYmUuY29tL3hhcC8xLjAvIiB4bWxuczp4bXBNTT0iaHR0cDovL25zLmFkb2JlLmNvbS94YXAvMS4wL21tLyIgeG1sbnM6c3RSZWY9Imh0dHA6Ly9ucy5hZG9iZS5jb20veGFwLzEuMC9zVHlwZS9SZXNvdXJjZVJlZiMiIHhtcDpDcmVhdG9yVG9vbD0iQWRvYmUgUGhvdG9zaG9wIENTNiAoV2luZG93cykiIHhtcE1NOkluc3RhbmNlSUQ9InhtcC5paWQ6OUM0QjNBQjkyQUQ2MTFFQTlCNUQ4RTIzNDE5RUIxNjciIHhtcE1NOkRvY3VtZW50SUQ9InhtcC5kaWQ6OUM0QjNBQkEyQUQ2MTFFQTlCNUQ4RTIzNDE5RUIxNjciPiA8eG1wTU06RGVyaXZlZEZyb20gc3RSZWY6aW5zdGFuY2VJRD0ieG1wLmlpZDo5QzRCM0FCNzJBRDYxMUVBOUI1RDhFMjM0MTlFQjE2NyIgc3RSZWY6ZG9jdW1lbnRJRD0ieG1wLmRpZDo5QzRCM0FCODJBRDYxMUVBOUI1RDhFMjM0MTlFQjE2NyIvPiA8L3JkZjpEZXNjcmlwdGlvbj4gPC9yZGY6UkRGPiA8L3g6eG1wbWV0YT4gPD94cGFja2V0IGVuZD0iciI/PtRHfPcAAAAzUExURZWVldfX18PDw62trZubm9zc3Li4uKGhoebm5tLS0uHh4c3Nzaenp729vcjIyLKysuvr6141L40AAAcXSURBVHja7NzZlqpGAEBR5lG0//9rIw7IJKJi4or7PGTdtN10wr5SVAEGf/qqArsAiIAAERAgAgJEQIAIiIAAERAgAgJEQIAIiIAAERAgAgJEQIAIiIAAERAgAgJEQIAIiIAAERAgAgJEQIAIiIAAERAgAgJEQIAIiIAAERAgAgJEQIAIiIAAERAgAgJEQIAIiIAAERAgAgJEQIAIiIAAERAgAgJEQIAICBABERAgAgJEQIAICBABERAgAgJEQIAICBABERAgAgJEQIAICBABERAgAgJEQIAICBABERAgAgJEQIAICBABERAgAgJEQIAICBABERAgAgJEQIAICBABERAgAgJEQIAICBABERAg+nmQFMi5Jis+sIniED23jSzIgLTtg2D//iYme/8QBM/9lQ+CAEhbNLM3N9hEHAThX7GPCiBfAxK1b51kD+R7QMLjXg7iCsgWIPUh7pfVozG791oeBPngm48G583uW5GkBvI+SBaM2xXDn1oqum423bX/mgF5FySc2cv93Voug9TdZotsggnkBZB2NzbhrSY5HnoG07jei8dvzsJB/c3W60SALILE46+WCztsbhPR7R2VJq0ukEcT49nyy8QhaKcRa3fYHZD4+ufqOJAcgDz8/59vtw1I3QP5K6JsOG0vm3hce4I8LQp/BaRZGJC3AAn7IKOKXbC+7EdA5vdmmVwOLksgRThqOqiH4XEGsht+peoPUE8U/jJIO5OLH4GEwUslV5G0PTBG5Uiw/Y2jyigO3l9HAHKv9PYb82LloH74dZBoBUgar+l48NsNvtD0fkez9iwrAvIYZDRCl+Xs149Hm/KZmQ+QjUCiO1ei4ru7EsgnQYrkznlQb7thCuRfAzlOAPN72427P4VA/i2Q/DKT/Ls/VR8fvIBsDZIuz7TPF6TCbnk4GJkB2RokejTjuE7/unlgCuSTIO0Cy+Plp6vDfnQlBchy8QtjSHVd3EgmK1bHLm+H6+nXYbz2DuQRSPnqoL7vvq0u70on4zvxgCyWD3b9UyDVdW24PaWaiGTnFZJwPIQAebDpIKheBIm7n124ZthMJipAlkqHO+IZkP1tbfzOJark/A7MgKyvvl60fRqkvXfhuow+t9+q00+0/yyBrK8ZngOtBzldhw2X9tvpNGty0gvkmbPeJ0Cy/r09s/stbmfo0yMWkEdjevgKyOn2t2pxv7UXoibTdCDLje9/Ww1ymqzn87dbp92242ZmMRjI8hASvwKSLq4udqN6ksw8nxXN3tszD9L8Gkg+2mFrQYql5az4tvFj5xOx4VwnSdeBtGdyPwUytxK77pBVlNHdO7OK3rh/eTPUvdutT3fO52tuHMqD4N7llv8pyOQQ//w19YVDfX27+Sfuby9/6nau4pdA8vEdOZuChEH/quHt0Jg+IRJ/5+PrHwKZXfjbDiS73Zo7mu5UkzX7uTsXe0e/7nC3ePf1O69+BUg2XDfZCqSqOu7rGVf8cHBe8zhC2b61dtUHXv0OkGo6ZL4JkpbRYXdUaFevivx2M/1GIOctNh949TtAoumQ+TpIHMX54CJu+8BDd8FkE5BqcZh/59XvAClmTvKfB0nDqIlHo3T70SftyW1eX9dXtgQJqs1f/Q6QaOa/7wmQKtxH8eiGoCRuovODIO3VxOMmruZbHrLyD7z6DSDtGyT7ew1kf9hNn07c986JTovzzem0Id9wUG+Vk/IDr34DSNR7huZJkMFT6vEhqrPx/j5cnlZML8N6/PAzh9Y99Flm5Yde/c9BquDOkvkKkMP58dA4qi9vivE8JOvGz/j8FokfPpr288+pH2ZPOZrLmeGD+7KOh6dqYWJ48ki7yUg0tz0go/fv/LLddfV3sgOLJyaGPY/zrSlh1a36Arkzoue9CyG35ze6E6/dzO2Ga0EGHqdRJIkfn9/8OEjTW8Vq91ZWh39FeehWA7Nu9ft8CpUEk1WWOyDF0OPyEU2Pnzf/bZC0P6IPzmAvu7KauQBVrgKpJ0tG2arHzX8e5Pb3PezNs/PrX+3JMyCLn9XXf37tPFHvt09WfCDDjx+yyn1/p1V11j7GnB/q3leLuVva79S/tzed+db08YpF4uOZtmz/9oXWMq6BCAgQAQEiIEAERECACAgQAQEiIEAERECACAgQAQEiIEAERECACAgQAQEiIEAERECACAgQAQEiIEAERECACAgQAQEiIEAERECACAgQAQEiIEAERECACAgQAQEiIEAERECACAgQAQEiIEAERECACAgQAQEiIEAEBIiACAgQAQEiIEAEBIiACAgQAQEiIEAEBIiACAgQAQEiIEAEBIiACAgQAQEiIEAEBIiACAgQAQEiIEAEBIiACAgQAQEiIEAEBIiACAgQAQEiIEAEBIiACAgQAQEiIEAEBIiACAgQAQEiIEAEBIiAALELvqt/BBgACqVeUBXxcCkAAAAASUVORK5CYII='
  55. },
  56. // 加载失败的错误占位图
  57. errorImg: {
  58. type: String,
  59. default: 'data:image/png;base64,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'
  60. },
  61. // 图片进入可见区域前多少像素前,单位rpx,开始加载图片
  62. // 负数为图片超出屏幕底部多少像素后触发懒加载,正数为图片顶部距离屏幕底部多少距离时触发(图片还没出现在屏幕上)
  63. threshold: {
  64. type: [Number, String],
  65. default: 100
  66. },
  67. // 是否开启过渡效果
  68. isEffect: {
  69. type: Boolean,
  70. default: true
  71. },
  72. // 动画过渡时间
  73. duration: {
  74. type: [String, Number],
  75. default: 500
  76. },
  77. // 渡效果的速度曲线,各个之间差别不大,因为这是淡入淡出,且时间很短,不是那些变形或者移动的情况,会明显
  78. // linear|ease|ease-in|ease-out|ease-in-out|cubic-bezier(n,n,n,n);
  79. effect: {
  80. type: String,
  81. default: 'ease-in-out'
  82. },
  83. // 图片高度,单位rpx
  84. height: {
  85. type: [String, Number],
  86. default: 450
  87. },
  88. // 图片圆角
  89. borderRadius: {
  90. type: String,
  91. default: ''
  92. }
  93. },
  94. computed: {
  95. thresholdValue() {
  96. // 先取绝对值,因为threshold可能是负数,最后根据this.threshold是正数或者负数,重新还原
  97. let threshold = uni.upx2px(Math.abs(this.threshold))
  98. return this.threshold < 0 ? -threshold : threshold
  99. },
  100. lazyLoadItemStyle() {
  101. let style = {}
  102. style.opacity = Number(this.opacity)
  103. if (this.borderRadius) {
  104. style.borderRadius = this.borderRadius
  105. }
  106. // 因为time值需要改变,所以不直接用duration值(不能改变父组件prop传过来的值)
  107. style.transition = `opacity ${this.time / 1000}s ${this.effect}`
  108. style.height = this.$t.string.getLengthUnitValue(this.height)
  109. return style
  110. },
  111. imageStyle() {
  112. let style = {}
  113. if (typeof this.height === 'string' && this.height.indexOf('%') === -1) {
  114. style.height = this.$t.string.getLengthUnitValue(this.height)
  115. }
  116. return style
  117. }
  118. },
  119. watch: {
  120. show(val) {
  121. // 如果不开启过渡效果直接返回
  122. if (!this.effect) return
  123. this.time = 0
  124. // 原来opacity为1(不透明,是为了显示占位图),改成0(透明,意味着该元素显示的是背景颜色,默认的白色),再改成1,是为了获得过渡效果
  125. this.opacity = 0
  126. setTimeout(() => {
  127. this.time = this.duration
  128. this.opacity = 1
  129. }, 30)
  130. },
  131. image(val) {
  132. // 修改图片后重置部分变量
  133. if (!val) {
  134. // 如果传入null或者'',或者undefined,标记为错误状态
  135. this.error = true
  136. } else {
  137. this.init()
  138. this.error = false
  139. }
  140. }
  141. },
  142. data() {
  143. return {
  144. elIndex: this.$t.uuid(),
  145. // 显示图片
  146. show: false,
  147. // 图片透明度
  148. opacity: 1,
  149. // 动画时间
  150. time: this.duration,
  151. // 懒加载状态
  152. // loadlazy-懒加载中状态,loading-图片正在加载,loaded-图片加加载完成
  153. loadStatus: '',
  154. // 图片加载失败
  155. error: false
  156. }
  157. },
  158. created() {
  159. // 由于一些特殊原因,不能将此变量放到data中定义
  160. this.observer = {}
  161. this.observerName = 'lazyLoadContentObserver'
  162. },
  163. mounted() {
  164. // 在需要用到懒加载的页面,在触发底部的时候触发tOnLazyLoadReachBottom事件,保证所有图片进行加载
  165. this.$nextTick(() => {
  166. uni.$once('tOnLazyLoadReachBottom', () => {
  167. if (!this.show) this.show = true
  168. })
  169. })
  170. // mounted的时候,不一定挂载了这个元素,延时30ms,否则会报错或者不报错,但是也没有效果
  171. setTimeout(() => {
  172. this.disconnectObserver(this.observerName)
  173. const contentObserver = uni.createIntersectionObserver(this)
  174. contentObserver.relativeToViewport({
  175. bottom: this.thresholdValue
  176. }).observe(`.tn-lazy-load__item--${this.elIndex}`, (res) => {
  177. if (res.intersectionRatio > 0) {
  178. // 懒加载状态改变
  179. this.show = true
  180. // 如果图片已经加载,去掉监听,减少性能消耗
  181. this.disconnectObserver(this.observerName)
  182. }
  183. })
  184. this[this.observerName] = contentObserver
  185. }, 50)
  186. },
  187. methods: {
  188. // 初始化
  189. init() {
  190. this.error = false
  191. this.loadStatus = ''
  192. },
  193. // 处理图片点击事件
  194. handleImgClick() {
  195. let whichImg = ''
  196. // 如果show为false,则表示图片还没有开始加载,点击的是最开始占位图
  197. if (this.show === false) whichImg = 'lazyImg'
  198. // 如果error为true,则表示图片加载失败,点击的是错误占位图
  199. else if (this.error === true) whichImg = 'errorImg'
  200. // 点击了正常的图片
  201. else whichImg = 'realImg'
  202. this.$emit('click', {
  203. index: this.index,
  204. whichImg: whichImg
  205. })
  206. },
  207. // 处理图片加载完成事件,通过show来区分是占位图触发还是加载真正的图片触发
  208. handleImgLoaded() {
  209. if (this.loadStatus = '') {
  210. // 占位图加载完成
  211. this.loadStatus = 'lazyed'
  212. }
  213. else if (this.loadStatus == 'lazyed') {
  214. // 真正的图片加载完成
  215. this.loadStatus = 'loaded'
  216. this.$emit('loaded', this.index)
  217. }
  218. },
  219. // 处理错误图片加载完成
  220. handleErrorImgLoaded() {
  221. this.$emit('error', this.index)
  222. },
  223. // 处理图片加载失败
  224. handleImgError() {
  225. this.error = true
  226. },
  227. disconnectObserver(observerName) {
  228. const observer = this[observerName]
  229. observer && observer.disconnect()
  230. }
  231. }
  232. }
  233. </script>
  234. <style lang="scss" scoped>
  235. .tn-lazy-load {
  236. &__item {
  237. background-color: $tn-bg-gray-color;
  238. overflow: hidden;
  239. &__image {
  240. // 解决父容器会多出3px的问题
  241. display: block;
  242. width: 100%;
  243. // 骗系统开启硬件加速
  244. transform: transition3d(0, 0, 0);
  245. // 防止图片加载“闪一下”
  246. will-change: transform;
  247. }
  248. }
  249. }
  250. </style>