之前在写自动安装APP这块碰到了不少问题，今天终于有时间来总结下

1.插件安装如下：
（1）文件插件

ionic cordova plugin add cordova-plugin-file
npm install @ionic-native/file

（2）文件传输插件

ionic cordova plugin add cordova-plugin-file-transfer
npm install @ionic-native/file-transfer

（3）文件打开插件

 ionic cordova plugin add cordova-plugin-file-opener2
 npm install @ionic-native/file-opener

2.代码流程如下

（1）从后台获取APP链接

let that = this;
const httpOptions = {
  headers: new HttpHeaders({ 'Content-Type': 'application/json', 'Authorization': localStorage.getItem('Authorization') }),
  withCredentials: true
}
this.appVersion.getVersionNumber().then(ver => {
  this.http.post(this.api +"', { 'appid': "", 'version_code': "" }, httpOptions).subscribe(
    async (response: any) => {
        that.targetUrl = response.data.app_version.download_url;
        that.showAlert();
    },
    err => {
      console.log(err)
    }
  )
})

(2)把APP安装到手机指定路径下并打开APP安装在手机上

downloadApp() {
let that = this;
const fileTransfer: FileTransferObject = this.transfer.create();
let saveurl = this.file.externalDataDirectory ? this.file.externalDataDirectory : this.file.dataDirectory;
let apk = saveurl + 'download/' + 'ezhear.apk';
fileTransfer.download(this.targetUrl, apk).then((entry) => {
  this.fileOpener.open(apk, "application/vnd.android.package-archive")
    .then((e) => {
      console.log('File is opened', e)
    })
    .catch(e => {
      console.log('Error openening file', e)
    });
}, (error) => {
  alert(JSON.stringify(error));
});
var progressNum = document.getElementById('progressnum');
/**下载进度条*/
fileTransfer.onProgress((event) => {
  let num = Math.ceil(event.loaded / event.total * 100);  //转化成1-100的进度
  if (num === 100) {
    progressNum.innerHTML = '下载完成';
  } else {
    progressNum.innerHTML = '下载进度：' + num + '%';
  }
});
}

插件下载链接地址如下：

(1) https://ionicframework.com/docs/native/file
(2) https://ionicframework.com/docs/native/file-opener
(3) https://ionicframework.com/docs/native/file-transfer