@groengeel, I would think that using the 'wait' command would prevent your scenario from catching any keystrokes until after the 'wait' was completed. @Sl3nDeRm4n, what is triggering the pause to catch a keystroke? are you like on a header screen? or, maybe at a menu? do you already have actors that automatically move in the world, or do you change world to perform the check for keystroke input? Giving appropriate information that deals with your situation goes a long way in providing the best answers possible.

i have actors that move and if one actor intersects a specifial other one it creates a new object in the first world. Then it opens a new world. I want to wait Greenfoot to wait with opening the new world until the spacebar is pressed. Could it work like this?

You should use a boolean to know when the first object intersects the other (or what ever should be the condition to add the new world). If this condition is meet the boolean should be true until there is the new world added. Then do this in your act method (of the world or where ever your setWorld is now):

Again, with that code you are hogging up all the CPU time while waiting for the keypress. Not a good programming practice. In your initial world, do any of your actors move on their own? or only by user control? If you are not worried about actors that move programatically roaming around, doing whatever they do, then you can code it right there in the class of the actor you determined the intersecting state in. This should be one for the first things in your 'act' method (or you can place this code within a seperate method and have it be one of the first method calls in your 'act' method).

I would like to know what the purpose is of waiting for the spacekey to be pressed before changing worlds. I would have to think it is in response to some message or something, but the likelihood of that would seem pretty slim. Also, I do not know what the new world is for (another level, a menu, something else).

Does it also work if my 'if' block isnt inthe class flag? or should i put the boolen just into the class of the intersecting object? And i have actors that move programmically around but its no problem if they stop

Im programming agame and if the player reachs the flag a new object appears with the massage that the lv is won. Then It shall open a new world after space key s pressed

The thing is, they will not stop while waiting for the keypress; unless you programatically halt them while waiting for the keypress. You could add a static boolean to the world class, called something like 'actorsHalted', set to 'false'. Then in all actor classes whose movements are programmed, add the following statement as the first statement in the 'act' method: Set 'actorsHalted' to 'true' when you set 'waitingForSpaceKey' to 'true'. The boolean 'waitingForSpaceKey' should be declared in the class (not within a method). The static boolean 'actorsHalted' should be declared in the world class (again, not within a method).

now it does not open directly and not if i press space could that be because in this class i have no act() method? Im working with a method Action which gets parameter from a subclass?

ok i fised it now: Greenfoot doesnt know space it might have another name if i write and not it works