import com.zhy.http.okhttp.callback.FileCallBack; //导入依赖的package包/类
/**
 * 下载更新文件
 */
private void downLoadUpdateFile() {
    String path = Environment.getExternalStorageDirectory().getAbsolutePath();
    OkHttpUtils.get().url(versionInfo.getDownloadUrl())
            .build()
            .connTimeOut(5000)
            .execute(new FileCallBack(path, "myQluUpdate.apk") {
                @Override
                public void inProgress(float progress, long total) {
                    System.out.println(total + "------" + progress * total);
                    pbDown.setMax((int) total);
                    pbDown.setProgress((int) (progress * total));
                }

                @Override
                public void onError(Call call, Exception e) {
                    handler.sendEmptyMessageDelayed(2, 1000);
                }

                @Override
                public void onResponse(File response) {
                    //下载成功。进入程序安装界面
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.addCategory(Intent.CATEGORY_DEFAULT);
                    intent.setDataAndType(Uri.fromFile(response),
                            "application/vnd.android.package-archive");
                    startActivityForResult(intent, 0);
                }
            });
}