在 long-运行 操作期间不显示进度微调器

Progress spinner not showing during long-running operation

我正在为 android 编写一个纸牌游戏应用程序。有时电脑播放器可能需要 1-3 秒才能播放,在此期间我想显示圆形不确定微调器。问题是微调器在此 "thinking" 时间内不显示,尽管它在测试中显示。

这是我的微调器片段:

    <ProgressBar
    android:id="@+id/progressCircle"
    style="?android:attr/progressBarStyleLarge"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/draw_and_discard_piles"
    android:layout_centerHorizontal="true"
    android:visibility="gone"/>

以及在 OnCreate 期间对其进行膨胀的相应代码片段:

    spinner = (ProgressBar)findViewById(R.id.progressCircle);
    spinner.setVisibility(View.GONE);

并显示它:

void showSpinner(final boolean show) {
    spinner.setVisibility(show ? View.VISIBLE : View.GONE);
    spinner.invalidate();
}

在长时间 运行 播放期间,我执行以下操作,其中 DiscardOrDrawThread 是一个内部 class:

    //if Computer, we decide here whether to draw or discard
    final long playerStartTime = System.currentTimeMillis();

    class DiscardOrDrawThread extends Thread {
        private Game.PileDecision pickFrom;
        DiscardOrDrawThread() {
            pickFrom = null;
        }

        @Override
        public void run() {
            pickFrom = tryDiscardOrDrawPile(isFinalTurn, deck.discardPile.peekNext(), deck.drawPile.peekNext());
        }
    }
    DiscardOrDrawThread discardOrDrawThread = new DiscardOrDrawThread();

    myActivity.showSpinner(true);
    try {
        discardOrDrawThread.start();
        discardOrDrawThread.join();
    }catch(RuntimeException e) {
        System.out.println("takeTurn: thread join RuntimeException");
    }catch (InterruptedException e) {
        throw new RuntimeException("Interrupted in takeTurn");
    }
    myActivity.showSpinner(false);

实际播放代码运行良好,如果我注释掉 myActivity.showSpinner(false),则微调器将正确显示,从 long-运行 部分的开头开始(tryDiscardOrDrawPile)。但如果不注释掉,微调器永远不会显示。

任何人都可以指出我做错了什么吗?

Progress spinner not showing during long-running operation

由于discardOrDrawThread.join();

Why?

discardOrDrawThread.join();导致当前线程(main UI-Thread)暂停执行直到discardOrDrawThread的线程终止

使用AsyncTask or runOnUiThread在后台进行长运行操作

我使用 AsyncTask 重新实现了我的代码(许多帖子建议使用 ProgressBars),如下所示,现在一切正常。

       class DiscardOrDrawTask extends AsyncTask<Void, Void, Game.PileDecision> {

        @Override
        protected Game.PileDecision doInBackground(Void... params) {
            final Game.PileDecision pickFrom = tryDiscardOrDrawPile(isFinalTurn, deck.discardPile.peekNext(), deck.drawPile.peekNext());
            return pickFrom;
        }

        @Override
        protected void onPreExecute() {
            myActivity.showSpinner(true);
        }

        @Override
        protected void onPostExecute(final Game.PileDecision pickFrom) {
            myActivity.showSpinner(false);
            myActivity.animateComputerPickUpAndDiscard(playerMiniHandLayout, pickFrom);
        }
    }
    DiscardOrDrawTask discardOrDrawTask= new DiscardOrDrawTask();
    discardOrDrawTask.execute();