public class MainActivity extends Activity {
  private ProgressDialog dialog;


  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initView();
  }
  private void initView() {
    AlertDialog.Builder dialogTips= new AlertDialog.Builder(this);
    dialogTips.setTitle("提示");
    dialogTips.setMessage("检测到有新的版本，是否更新？");
    dialogTips.setNegativeButton("取消", null);
    dialogTips.setPositiveButton("更新", new OnClickListener() {

      @Override
      public void onClick(DialogInterface arg0, int arg1) {
        startDownload();
      }
    });
    dialogTips.show();

    dialog=new ProgressDialog(this);
    dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
    dialog.setMessage("更新应用");
    dialog.setMax(100);
  }
  private void startDownload(){
    //定义保存的文件地址为根目录
    File path = new File(Environment.getExternalStorageDirectory(),
        "大众点评"+ ".apk");
    httpDownLoad(path.getPath(), "http://www.wandoujia.com/apps/com.dianping.v1/download");

  }

  /**
   * 下载的方法
   * @param path 文件保存的路径
   * @param url 下载的地址
   */
  private void httpDownLoad(String path, String url) {
    HttpUtils http = new HttpUtils();
    http.download(url, path, true, true, new RequestCallBack<File>() {

      @Override
      public void onStart() {
        super.onStart();
        dialog.show();
      }

      @Override
      public void onLoading(long total, long current, boolean isUploading) {
        int index = (int) (current * 100 / total);
        dialog.setProgress(index);
      }


      @Override
      public void onSuccess(ResponseInfo<File> responseInfo) {
        //获取到安装包后，调用系统的android安装apk界面进行安装 这是固定格式
        Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setDataAndType(
            Uri.fromFile(new File(responseInfo.result.getPath())),
            "application/vnd.android.package-archive");
        startActivity(intent);
        dialog.dismiss();
        MainActivity.this.finish();
      }

      @Override
      public void onFailure(
          com.lidroid.xutils.exception.HttpException arg0, String arg1) {
        File path = new File(Environment.getExternalStorageDirectory(),
            "大众点评" + ".apk");
        Toast.makeText(MainActivity.this, "下载失败"+arg1, 0).show();
        dialog.dismiss();
        path.delete();
      }
    });
  }

}