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我有几个TimerViews 的活动。TimerView 是从 textview 扩展而来的自定义视图，用户可以单击它来开始倒计时。

每个 TimerView 都拥有一个 Timer。现在的问题是，当我更改屏幕的方向时，TimerViews 被重置（当前文本被删除（更改为“”）但运行时对 bakground 的更改被保留），但处理程序线程仍在运行，正在更新TimerViews 不再存在（？）。

在方向改变之前发送的消息仍然有效。发送这些消息的线程（？）何时终止？

解决这个问题的正确方法是什么。将 Timers 的引用更新到新活动的 TimerViews，或者删除 Timers 并创建新的？还是其他更正确的解决方案？感谢所有建设性的批评！

我发布了我认为相关的代码部分：

TimerView 扩展了 TextView

public class TimerView extends TextView implements View.OnClickListener
{
    private SecondTimer secondTimer;

    public TimerView(Context context, AttributeSet attrs)
    {
        super(context, attrs);

        secondTimer = new SecondTimer(120, this);
        setOnClickListener(this);
    }

    @Override
    public void onClick(View view)
    {
        if(!secondTimer.isRunning())
            secondTimer.start();
    }
}

秒计时器

// 这里派生自 Sam 的计时器android CountDownTimer - 滴答之间的额外毫秒延迟

public abstract class SecondTimer 
{
    private final long millisInFuture;
    private final long countdownInterval;
    private long stopTimeInFuture;
    private long nextTime;
    private boolean running;

    // Reference to TimerView that this timer should update
    TimerView timerView;

    // Constructor
    public SecondTimer(long secondsInFuture, TimerView timerView)
    {        
        this.millisInFuture = secondsInFuture * 1000;
        this.countdownInterval = 1000;
        this.timerView = timerView;
    }


    private static final int MSG = 1;
    public synchronized SecondTimer start() //Synch needed?
    {
        running = true;

        if(millisInFuture <= 0)
        {
            onFinish();
            return this;
        }

        nextTime = SystemClock.uptimeMillis();
        stopTimeInFuture = nextTime + millisInFuture;

        // Message for start tick
        handler.sendMessage(handler.obtainMessage(MSG));
        return this;
    }

    // Takes care of counting down
    private Handler handler = new Handler()
    {
        @Override
        public void handleMessage(Message msg)
        {
            synchronized(SecondTimer.this)
            {
                final long millisLeft = stopTimeInFuture - SystemClock.uptimeMillis();

                if(millisLeft <= 0)
                {
                    onFinish();
                }
                else
                {
                    onTick(millisLeft);

                    long currentTime = SystemClock.uptimeMillis();
                    do
                    {
                        nextTime += countdownInterval;
                    } while(currentTime > nextTime);

                    // Make sure this interval doesn't exceed the stop time
                    if(nextTime < stopTimeInFuture)
                        sendMessageAtTime(obtainMessage(MSG), nextTime);
                    else
                        sendMessageAtTime(obtainMessage(MSG), stopTimeInFuture);
                }
            }
        }
    };

    private void onTick(long millisUntilFinished)
    {
        long secondsUntilFinished = (millisUntilFinished + 500) / 1000;
        long minutesUntilFinished = secondsUntilFinished / 60;
        secondsUntilFinished %= 60;

        timerView.setText(String.format("%01d", minutesUntilFinished)
                + ":"
                + String.format("%02d", secondsUntilFinished));
    }

    private void onFinish()
    {
        running = false;
    }

    public boolean isRunning()
    {
        return running;
    }
}
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1 回答 1

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一种方法是将您的计时器移动到 setRetainInstance(true) 片段。这样的片段不会在方向改变时被破坏。（顺便说一句，最好不要在保留的片段中更新 UI。）

于 2013-08-06T18:16:36.927 回答