Cocos2D - CCLabelTTF - waiting for end of running actions - objective-c

Question

simply, before I start new level of my game, I show countdown (using CCLabelTTF, Cocos2D).
I have this code:
centerLevelLabel.string=#"New level";
centerLevelLabel.visible=true;
[centerLevelLabel runAction:[CCFadeOut actionWithDuration:1]];
while (centerLevelLabel.numberOfRunningActions>0) {
}
centerLevelLabel.string=#"3";
while (centerLevelLabel.numberOfRunningActions>0) {
}
centerLevelLabel.string=#"2";
while (centerLevelLabel.numberOfRunningActions>0) {
}
centerLevelLabel.string=#"1";
while (centerLevelLabel.numberOfRunningActions>0) {
}
//some code bellow
I want to show thist label and then I need continue with code bellow. Problem is, that UI is freezed and in first while block is running infinite loop. But i don`t kwon why, because when running actions is finished, numberOfRunningActions is zero.
Is there any other way, how could I wait for end of running actions and then continue?
Thank you

Answer 1

You could serialize the action by using a CCSequence and add the CCCallFuncN to execute some code after the original action completes.
id action1 = [CCFadeOut actionWithDuration:1];
id action2 = [CCCallFuncN actionWithTarget:self selector:#selector(finishedRunning)];
id sequenceActions = [CCSequence actions:action1, action2, nil]];
[centerLevelLabel runAction:sequenceActions];
....
-(void) finishedRunning {
// Do stuff after action finishes
}

Answer 2

This will always be an infinite loop:
while (centerLevelLabel.numberOfRunningActions > 0)
{
}
It's similar to writing:
while (value > 0)
{
}
For the time the while loop is running, the thread is blocked. Therefore no other code will run that updates the number of actions, or that might change the value of value.