app下载app 有进度条

uniapp开发，app的webview页面，app内下载其他app，需要给一个apk的下载地址

export default { update(fileName) { let downURL = fileName; //后台显示进度条 let isapk=uni.getStorageSync('apk') console.log('下载地址', isapk); if(isapk){ uni.showModal({ title: "下载完成", content: "请点击允许安装应用", success: (res) => { if (res.confirm) { install(isapk, 200); }else{ signOut() } }, }); }else{ let dtask = plus.downloader.createDownload( downURL, {}, function(d, status) { //下载完成 uni.setStorageSync('apk',d) uni.showModal({ title: "下载完成", content: "请点击允许安装应用", success: (res) => { if (res.confirm) { install(d, status); }else{ signOut() } }, }); } ); start(dtask); } } } function start(dtask) { try { dtask.start(); //开启下载项目 let prg = 0; let showLoading = plus.nativeUI.showWaiting("正在下载"); dtask.addEventListener("statechanged", function(task, status) { switch (task.state) { case 1: showLoading.setTitle("正在下载"); break; case 2: showLoading.setTitle("已连接到服务器"); break; case 3: prg = parseInt( (parseFloat(task.downloadedSize) / parseFloat(task.totalSize)) * 100 ); showLoading.setTitle(" 正在下载" + prg + "% "); break; case 4: plus.nativeUI.closeWaiting(); break; } }); } catch (err) { plus.nativeUI.closeWaiting(); uni.showToast({ title: "更新失败-03", mask: false, duration: 1500, }); } }; function install(d, status) { //下载完成 if (status === 200) { plus.runtime.install(d.filename, { force: false }, function() { plus.nativeUI.closeWaiting(); uni.removeStorageSync('apk') }, function(e) { plus.nativeUI.closeWaiting(); uni.removeStorageSync('apk') console.log("安装wgt文件失败[" + e.code + "]：" + e.message); plus.nativeUI.alert("安装wgt文件失败[" + e.code + "]：" + e.message); }); } else { uni.showToast({ title: "下载失败", mask: false, duration: 1500, }); } };