1：使用html PLUS实现：地址HTML5+ API Reference (html5plus.org)，效果图

2：在app.vue的onLaunch生命周期中，代码如下：

onLaunch: function() {let a = 0let view = new plus.nativeObj.View('maskView', {backgroundColor: "rgba(0,0,0,.6)",left: ((plus.screen.resolutionWidth / 2) - 150) + "px",bottom: ((plus.screen.resolutionHeight / 2) - 100) + "px",width: "300px",height: "200px",radius: "15px"})view.drawText('APP新版本更新', {top: '-80px',left: '0px'}, {size: '26px',color: '#FFFFFF'});//更新消息格式化var richText ='<font color = "#FF0000" style = "font-size:20px;"> 1:更新了11111。</font><br/><font color = "#FF0000" style = "font-size:20px;"> 2:更新了222。</font>';// let richText1 = richText.replace(/。/g, '。<br/>')view.drawRichText(richText, {top: '40px',left: '50px',width: '100%',height: 'wrap_content',})view.drawText('下载进度:0%', {top: '40px',left: '0px'}, {size: '18px',color: '#FFFFFF'}, 'xzjd');view.drawRect({color: '#6a8aff',radius: '10px'}, {bottom: '30px',width: '100%',height: '20px',});view.drawRect({radius: '10px',color: '#55ff00'}, {bottom: '30px',width: 0 + '%',height: '20px',}, 'jdt');view.show()let b = setInterval(() => {//根据自己需要，把这个定时器更换为监听下载进度的方法，以下代码介绍a++view.drawRect({color: '#55ff00',radius: '10px'}, {bottom: '30px',width: a + '%',height: '20px',}, 'jdt');view.drawText('下载进度:' + a + '%', {top: '40px',left: '0px'}, {size: '18px',color: '#FFFFFF'}, 'xzjd');if (a >= 100) {clearInterval(b)view.drawText('已完成', {top: '40px',left: '0px'}, {size: '20px',color: '#FFFFFF'}, 'xzjd');}}, 300)console.log('App Launch')}

3：这只是样式，需要把定时器更换为监听下载进度的方法

var dtask = plus.downloader.createDownload(//下载事件，有一个返回值downUrl, {filename: "_downloads/"},function(d, status) {// 下载完成if (status == 200) {plus.runtime.install(d.filename, {force: true}, function() {//进行重新启动;plus.runtime.restart();}, (e) => {uni.showToast({title: '安装升级包失败:' +JSON.stringify(e),icon: 'none'})});} else {http.hint("下载升级包失败，请联系管理员，错误码: " +status)}
});
dtask.addEventListener("statechanged", (e) => {if (e && e.downloadedSize > 0) {let jindu = ((e.downloadedSize / e.totalSize) * 100).toFixed(2)///把上面定时器的代码放进来，a替换成jindu变量}
}, false);
dtask.start();