Android Widget：进度条不可见

Question

我试图在App小部件中显示不确定的进度条2秒钟（以表明数据正在刷新）。 但是小部件没有显示。 我尝试使用Handler.postdelayed和Thread.sleep。 两种方法均无效。 该小部件根本没有显示。

在小部件布局中

    <ProgressBar
        style="?android:attr/progressBarStyleLargeInverse"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/widget_progress_bar"
        android:layout_centerInParent="true"
        android:indeterminate="false" />

我什至尝试了StyleHorizo​​ntal的酒吧风格。

在AppWidgetProvider类中

首先在updateAppWidget（）方法上调用它：

方法1：新线程

 public static void updateAppWidget(Context context, AppWidgetManager appWidgetManager, int appWidgetId) {
          final RemoteViews widgetView = new RemoteViews(context.getPackageName(), R.layout.widget_wifi_info_basic);
                  new Thread(new Runnable() {
            int progress = 0;
            Handler progressHandler = new Handler();
            public void run() {
                long timerEnd = System.currentTimeMillis() + 3 * 1000;

                while (timerEnd >  System.currentTimeMillis() ) {

                    progress = (int) (timerEnd - System.currentTimeMillis()) / 300;
                    // Update the progress bar
                    progressHandler.post(new Runnable() {
                        public void run() {
                            widgetView.setProgressBar(R.id.widget_progress_bar,3000,progress,false);
                            Log.d("tag", "progress=" +progress);
                        }
                    });
                    try {
                        Thread.sleep(300);
                    } catch (InterruptedException e) {
                        Log.w("tag","Progress thread cannot sleep");
                    }
                }
            }
        }).start();
        ...
        ...
  }

方法2：CountdownTimer（再次在同一方法内）

widgetView.setViewVisibility(R.id.widget_progress_bar,View.VISIBLE);
        new CountDownTimer(2000, 100) {
            @Override
            public void onTick(long millisUntilFinished) {
                //this will be done every 1000 milliseconds ( 1 seconds )
                int progress = (2000 - (int)millisUntilFinished) / 100;
                widgetView.setProgressBar(R.id.widget_progress_bar,2000,progress,false);
                Log.d(Constants.APP_NAME, "progress=" +progress);
            }

            @Override
            public void onFinish() {
                //the progressBar will be invisible after 2 seconds
      widgetView.setViewVisibility(R.id.widget_progress_bar,View.INVISIBLE);
            }

        }.start();

方法3：尝试不确定的进度条; 线程休眠

        // sleep for few seconds
        try {
            // Show progress bar
            widgetView.setViewVisibility(R.id.widget_progress_bar, View.VISIBLE);
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            Log.w("tag","Progress thread cannot sleep");
        }
        // Hide progress bar
        widgetView.setViewVisibility(R.id.widget_progress_bar, View.INVISIBLE);

令人惊讶的是，日志消息（用于打印进度）从未被打印！

Answer 1

为进度栏创建单独的线程，然后运行2秒钟。