前一段时间做项目，频繁使用到上传图片组件，而且只上传一个封面，于是想着自定义一个图片封面上传组件。先来看一下效果：
第一张图片是上传之前，第二张图片是上传成功后，第3张图片是鼠标放上去之后的效果！
首先整理需求，图片上传我们使用照片墙的方式，只能上传一张图片，图片上传成功后不能继续上传，如果想要更换图片，则需要将图片删除后重新上传。点击图片上面的放大镜可以查看大图。
需要限制图片上传的格式，图片的大小。
组件代码：
1 <template>
2 <div class="upload">
3 <el-upload
4 :class="{'hidden':mFileList.length > 0}"
5 list-type="picture-card"
6 :on-remove="handleRemove"
7 :action="action"
8 :before-upload="beforeUploadHandle"
9 :on-success="successHandle"
10 :on-change="changeHandle"
11 :limit="1"
12 :accept="accept"
13 :on-exceed="handleExceed"
14 :file-list="fileList"
15 :on-preview="handlePictureCardPreview"
16 >
17 <i class="el-icon-plus"></i>
18 </el-upload>
19 <el-dialog :visible.sync="dialogVisible">
20 <img width="100%" :src="dialogImageUrl" alt="" />
21 </el-dialog>
22 </div>
23 </template>
24
25 <script>
26 export default {
27 props: {
28 action: {
29 type: String,
30 default: "",
31 },
32 accept: {
33 type: String,
34 default: "",
35 },
36 fileList:{
37 type: Array,
38 default: () => [],
39 },
40 },
41 watch: {
42 fileList(newValue, oldValue) {
43 this.mFileList = newValue
44 }
45 },
46 data() {
47 return {
48 dialogVisible: false, //图片放大
49 fileImg: "", //上传图片
50 dialogImageUrl: "", //图片地址
51 mFileList:this.fileList,
52 };
53 },
54 methods: {
55 handleRemove(file, fileList) {
56 this.$emit("upload-remove", file);
57 },
58 handlePictureCardPreview(file) {
59 this.dialogImageUrl = file.url;
60 this.dialogVisible = true;
61 },
62 // 上传之前
63 beforeUploadHandle(file) {
64 if (file.type !== "image/jpeg" && file.type !== "image/png") {
65 this.$message({
66 message: "只支持jpg、png格式的图片！",
67 type: "warning",
68 });
69 return false;
70 }
71 const isLt2M = file.size / 1024 / 1024 < 2;
72 if (!isLt2M) {
73 this.$message({
74 message: "上传文件大小不能超过 2MB!",
75 type: "warning",
76 });
77 return false;
78 }
79 },
80 // 上传成功
81 successHandle(response, file, fileList) {
82 this.mFileList = fileList;
83 if (response && response.code === 200) {
84 this.$message.success("图片上传成功！");
85 this.$emit("upload-success", response, file);
86 } else {
87 this.$message.error(response.msg);
88 }
89 },
90 changeHandle(file, fileList) {
91 if(file.response && file.response.code == 500) {
92 this.$emit("upload-error",file);
93 }
94 },
95 handleExceed(files, fileList) {
96 this.$message.warning("只能上传1张图片！");
97 },
98 },
99 };
100 </script>
101 <style lang="scss">
102 .upload .hidden .el-upload--picture-card {
103 display: none;
104 }
105 </style>
调用组件代码：
1 <template>
2 <div>
3 <el-form ref="dataForm" label-width="80px">
4 <el-form-item label="封面" prop="cover" class="is-required">
5 <upload list-type="picture-card" :action="url" :accept="'.jpg,.png,.JPG,.PNG'" :fileList="fileList"
6 :limit="1" @upload-success="uploadFile" @upload-remove="removeFile" @upload-error="uploadError">
7 </upload>
8 </el-form-item>
9 </el-form>
10 </div>
11 </template>
12
13 <script>
14 import Upload from '../components/cover-upload/index.vue'
15 export default {
16 components: {
17 Upload
18 },
19 data() {
20 return {
21 url: "",
22 fileList: [],
23 }
24 },
25 methods: {
26 uploadUrl() {
27 this.url = "http://xxx.xxx.xxx.xxx:xxx/yyxt/admin/course/courseInfo/upload?token=075de0303b15a38833a30a7a3b494794"//上传图片的后台接口
28 },
29 uploadError(file) {
30 this.fileList = [];
31 },
32 uploadFile(response, file) {
33 this.fileList = [{
34 url: response.data,
35 }, ];
36 },
37 removeFile(file) {
38 this.fileList = [];
39 },
40 },
41 mounted() {
42 this.uploadUrl();
43 }
44 }
45 </script>
点击上传后的图片上的放大镜，显示图片大图
