Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
302 views
in Technique[技术] by (71.8m points)

java - Pause and Resume AsyncTasks? (Android)

I have an AsyncTask that acts as a countdown timer for my game. When it completes the countdown it displays the out of time end screen and it also updates the timer displayed on the screen. Everything works fine, except I need to be able to pause and resume this when the pause button in the game is pressed.

If I cancel it and try to re-execute it, it crashes with an IllegalStateException. If I cancel it and instantiate a new AsyncTask in its place the old one begins to run again and the new one runs at the same time.

Is there a way to cancel/pause the timer and restart it using AsyncTasks or is there a different way I should be going about doing this?

EDIT:

This is what I did for a solution:

mhandler = new Handler();

        mtimerTask = new Runnable(){
                public void run(){
                    mtimer -= 1;
                    if(mtimer == 0)
                    {
                        mhandler.removeCallbacks(this);
                    }
                    mhandler.postDelayed(this, 1000);
                }
        };
        mhandler.removeCallbacks(mtimerTask);
        mhandler.post(_timerTask)`

Not sure if it's the best way to go about it, but it worked for me.

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

I have an AsyncTask that acts as a countdown timer for my game.

That is not a good use of AsyncTask. AsyncTasks should do work and be done, not try hanging around. For a countdown timer, use postDelayed() -- you don't even need a background thread. Or, use CountDownTimer.

If I cancel it and try to re-execute it, it crashes with an IllegalStateException.

The documentation states: "The task can be executed only once (an exception will be thrown if a second execution is attempted.)"


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...