app级的build.gradle导入：

implementation'cn.bingoogolapple:bga-progressbar:1.0.0@aar'

implementation"com.android.support:cardview-v7:27.1.1"

implementation'cn.bingoogolapple:bga-update:1.0.2@aar'

Activity中：

private DownloadingDialogmDownloadingDialog;

@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_splash);

    BGAUpgradeUtil.getDownloadProgressEventObservable().subscribe(downloadProgressEvent -> {

        if (mDownloadingDialog !=null &&mDownloadingDialog.isShowing() && downloadProgressEvent.isNotDownloadFinished()) {

                    mDownloadingDialog.setProgress(downloadProgressEvent.getProgress(), downloadProgressEvent.getTotal());

         }

    });

}

/**

* 下载新版 apk 文件

*/

public void downloadApkFile(String mApkUrl,String mNewVersion) {

    // 如果新版 apk 文件已经下载过了，直接 return，此时不需要开发者调用安装 apk 文件的方法，在 isApkFileDownloaded 里已经调用了安装」

    if (BGAUpgradeUtil.isApkFileDownloaded(mNewVersion)) {

                return;

    }

    // 下载新版 apk 文件

    BGAUpgradeUtil.downloadApkFile(mApkUrl, mNewVersion).subscribe(new Subscriber() {

                @Override

                public void onStart() {

                    showDownloadingDialog();

                }

                @Override

                public void onCompleted() {

                    dismissDownloadingDialog();

                }

                    @Override

                public void onError(Throwable e) {

                        dismissDownloadingDialog();

                        ToastUtils.showShort(SplashActivity.this,"网络异常，请稍后重试");

                }

                @Override

                public void onNext(File apkFile) {

                    if (apkFile !=null) {

                           BGAUpgradeUtil.installApk(apkFile);

                     }

                 }

            });

}

/**

* 显示下载对话框

*/

private void showDownloadingDialog() {

    if (mDownloadingDialog ==null) {

        mDownloadingDialog =new DownloadingDialog(this);

    }

        mDownloadingDialog.show();

}

/**

* 隐藏下载对话框

*/

private void dismissDownloadingDialog() {

    if (mDownloadingDialog !=null) {

        mDownloadingDialog.dismiss();

    }

}

最后在是否更新弹框的确定按钮点击事件下：

downloadApkFile(versionBean.getData().getUrl(),versionBean.getData().getVersion());