|
5 | 5 | */ |
6 | 6 |
|
7 | 7 | class ImgLoader { |
8 | | - /** |
9 | | - * 初始化方法，在页面的 onLoad 方法中调用，传入 Page 对象及图片加载完成的默认回调 |
10 | | - */ |
11 | | - constructor(pageContext, defaultCallback) { |
12 | | - this.page = pageContext |
13 | | - this.defaultCallback = defaultCallback || function(){} |
14 | | - this.callbacks = {} |
15 | | - this.imgInfo = {} |
| 8 | + /** |
| 9 | + * 初始化方法，在页面的 onLoad 方法中调用，传入 Page 对象及图片加载完成的默认回调 |
| 10 | + */ |
| 11 | + constructor(pageContext, defaultCallback) { |
| 12 | + this.page = pageContext |
| 13 | + this.defaultCallback = defaultCallback || function(){} |
| 14 | + this.callbacks = {} |
| 15 | + this.imgInfo = {} |
16 | 16 |
|
17 | | - this.page.data.imgLoadList = [] //下载队列 |
18 | | - this.page._imgOnLoad = this._imgOnLoad.bind(this) |
19 | | - this.page._imgOnLoadError = this._imgOnLoadError.bind(this) |
20 | | - } |
| 17 | + this.page.data.imgLoadList = [] //下载队列 |
| 18 | + this.page._imgOnLoad = this._imgOnLoad.bind(this) |
| 19 | + this.page._imgOnLoadError = this._imgOnLoadError.bind(this) |
| 20 | + } |
21 | 21 |
|
22 | | - /** |
23 | | - * 加载图片 |
24 | | - * |
25 | | - * @param {String} src 图片地址 |
26 | | - * @param {Function} callback 加载完成后的回调（可选），第一个参数个错误信息，第二个为图片信息 |
27 | | - */ |
28 | | - load(src, callback) { |
29 | | - if (!src) return; |
| 22 | + /** |
| 23 | + * 加载图片 |
| 24 | + * |
| 25 | + * @param {String} src 图片地址 |
| 26 | + * @param {Function} callback 加载完成后的回调（可选），第一个参数个错误信息，第二个为图片信息 |
| 27 | + */ |
| 28 | + load(src, callback) { |
| 29 | + if (!src) return; |
30 | 30 |
|
31 | | - let list = this.page.data.imgLoadList, |
32 | | - imgInfo = this.imgInfo[src] |
| 31 | + let list = this.page.data.imgLoadList, |
| 32 | + imgInfo = this.imgInfo[src] |
33 | 33 |
|
34 | | - if (callback) |
35 | | - this.callbacks[src] = callback |
| 34 | + if (callback) |
| 35 | + this.callbacks[src] = callback |
36 | 36 |
|
37 | | - //已经加载成功过的，直接回调 |
38 | | - if (imgInfo) { |
39 | | - this._runCallback(null, { |
40 | | - src: src, |
41 | | - width: imgInfo.width, |
42 | | - height: imgInfo.height |
43 | | - }) |
44 | | - |
45 | | - //新的未在下载队列中的 |
46 | | - } else if (list.indexOf(src) == -1) { |
47 | | - list.push(src) |
48 | | - this.page.setData({ 'imgLoadList': list }) |
49 | | - } |
50 | | - } |
| 37 | + //已经加载成功过的，直接回调 |
| 38 | + if (imgInfo) { |
| 39 | + this._runCallback(null, { |
| 40 | + src: src, |
| 41 | + width: imgInfo.width, |
| 42 | + height: imgInfo.height |
| 43 | + }) |
| 44 | + |
| 45 | + //新的未在下载队列中的 |
| 46 | + } else if (list.indexOf(src) == -1) { |
| 47 | + list.push(src) |
| 48 | + this.page.setData({ 'imgLoadList': list }) |
| 49 | + } |
| 50 | + } |
51 | 51 |
|
52 | | - _imgOnLoad(ev) { |
53 | | - let src = ev.currentTarget.dataset.src, |
54 | | - width = ev.detail.width, |
55 | | - height = ev.detail.height |
| 52 | + _imgOnLoad(ev) { |
| 53 | + let src = ev.currentTarget.dataset.src, |
| 54 | + width = ev.detail.width, |
| 55 | + height = ev.detail.height |
56 | 56 |
|
57 | | - //记录已下载图片的尺寸信息 |
58 | | - this.imgInfo[src] = { width, height } |
59 | | - this._removeFromLoadList(src) |
| 57 | + //记录已下载图片的尺寸信息 |
| 58 | + this.imgInfo[src] = { width, height } |
| 59 | + this._removeFromLoadList(src) |
60 | 60 |
|
61 | | - this._runCallback(null, { src, width, height }) |
62 | | - } |
| 61 | + this._runCallback(null, { src, width, height }) |
| 62 | + } |
63 | 63 |
|
64 | | - _imgOnLoadError(ev) { |
65 | | - let src = ev.currentTarget.dataset.src |
66 | | - this._removeFromLoadList(src) |
67 | | - this._runCallback('Loading failed', { src }) |
68 | | - } |
| 64 | + _imgOnLoadError(ev) { |
| 65 | + let src = ev.currentTarget.dataset.src |
| 66 | + this._removeFromLoadList(src) |
| 67 | + this._runCallback('Loading failed', { src }) |
| 68 | + } |
69 | 69 |
|
70 | | - //将图片从下载队列中移除 |
71 | | - _removeFromLoadList(src) { |
72 | | - let list = this.page.data.imgLoadList |
73 | | - list.splice(list.indexOf(src), 1) |
74 | | - this.page.setData({ 'imgLoadList': list }) |
75 | | - } |
| 70 | + //将图片从下载队列中移除 |
| 71 | + _removeFromLoadList(src) { |
| 72 | + let list = this.page.data.imgLoadList |
| 73 | + list.splice(list.indexOf(src), 1) |
| 74 | + this.page.setData({ 'imgLoadList': list }) |
| 75 | + } |
76 | 76 |
|
77 | | - //执行回调 |
78 | | - _runCallback(err, data) { |
79 | | - let callback = this.callbacks[data.src] || this.defaultCallback |
80 | | - callback(err, data) |
81 | | - delete this.callbacks[data.src] |
82 | | - } |
| 77 | + //执行回调 |
| 78 | + _runCallback(err, data) { |
| 79 | + let callback = this.callbacks[data.src] || this.defaultCallback |
| 80 | + callback(err, data) |
| 81 | + delete this.callbacks[data.src] |
| 82 | + } |
83 | 83 | } |
84 | 84 |
|
85 | 85 | module.exports = ImgLoader |
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