暂停Java GUI中的执行

Question

I am writing a quiz program for the Android (written in Java). When the user answers a question (by clicking a button), I want to flash a message on the screen saying whether they were correct or not, followed by a 5 second pause before moving on to the next question.

However, when an answer button is clicked, the program pauses, but does not display the message of correct/incorrect. The message only comes up once the sleep method has finished.

if (correct)   
    Answer.setText("CORRECT!"); 
else 
    Answer.setText("WRONG!"); 

try { Thread.sleep(5000); } 
catch(InterruptedException e) {}

As a bonus, I'd like the answer buttons to be disabled during the pause.

Answer 1

You'll need an AsyncTask for that. Google gives you an intro to it here .

When you Thread.sleep() on the main Activity, you are putting the application to sleep. The AsyncTask will allow you to pause for the 5 seconds, maybe show a little In Progress bar and then pick up from there, without freezing the screen.

Answer 2

Imo AsyncTask is too much for this usecase.

Don't use sleep. Instead set your correct/incorrect message and than do this:

new Handler().postDelayed(new Runnable(){
  public void run()
  {
    goToNextScreen();
  }
}
, 5000);

Answer 3

Use a Handler : you can send a message with a 5000 millisecond delay, disable the buttons and when the message arrives you can re-enable the buttons. See http://www.tutorialforandroid.com/2009/01/using-handler-in-android.html for more info.

Answer 4

You should look into using timers for this. I don't think using threads are sensible for this. Using a timer to move onto the next question would work.

Look at timers here

Hope this helps.

Disclaimer: I have only used timers in Java to do something similar but i'm sure it would work in Android.