html:代碼
<div class="btnWrap" style="margin-top:30px;">
<el-button type="success" @click="downLoad_lower">線下二維碼下載下傳</el-button>
</div>
背景請求圖檔位址:
// 線下二維碼下載下傳
downLoad_lower() {
let data = {
type: 2,
id: this.id
};
queryGoodsQRCode(data).then(res => {
console.log(res);
if (res.data.messageCode == "MSG_1001") {
this.download(res.data.content);
} else {
this.$message.error(res.data.message);
}
});
},
下載下傳圖檔:
// 下載下傳檔案
download(data) {
if (!data) {
return;
}
this.getUrlBase64(data).then(base64 => {
let a = document.createElement("a");
a.style.display = "none";
a.download = this.name;
a.href = base64;
document.body.appendChild(a);
a.click();
});
},
注意:
這裡有一個坑。如果你的圖檔是從背景請求過來的,如果你的a标簽的href是IP位址的話,此時a标簽的download屬性會失效,a會被當成一個普通的連結使用。
解決方法1:将要下載下傳的圖檔連結轉換為base64格式,防止發生路由跳轉
getUrlBase64(url) {
return new Promise(resolve => {
let canvas = document.createElement("canvas");
let ctx = canvas.getContext("2d");
let img = new Image();
img.crossOrigin = "Anonymous"; //允許跨域
img.src = url;
img.onload = function() {
canvas.height = 300;
canvas.width = 300;
ctx.drawImage(img, 0, 0, 300, 300);
let dataURL = canvas.toDataURL("image/png");
canvas = null;
resolve(dataURL);
};
});