How to delay the appearance of sprites? - objective-c

Question

I am almost done with the app I'm currently making but I'm having a hard time trying to figure out one feature I need for it. I have 5 different sprites that drop on the screen on random intervals and positions. My problem is I need to tell my code that for a certain amount of time, for example 20 seconds, only 1 of the sprites would appear at a time. Then after 20 seconds, more would start dropping at the same time. Here's how my method looks like for dropping the sprites:
//The init method
-(id) init
{
if((self=[super init])) {
//Enable touch
self.isTouchEnabled = YES;
//Allocate and initialise
sprites = [[NSMutableArray alloc]init];
CGSize winSize = [[CCDirector sharedDirector]winSize];
//Add the sprites
[self schedule:#selector(scheduleDrop:)interval:2.0];
}
return self;
}
//Method to drop sprites
-(void)spriteDrop
{
CGSize winSize = [[CCDirector sharedDirector]winSize];
int RandomX = (arc4random() % 200);
NSString *strSprite = #"1.png";
switch(arc4random() % 5){
case 1:
strSprite = #"1.png";
break;
case 2:
strSprite = #"2.png";
break;
case 3:
strSprite = #"3.png";
break;
case 4:
strSprite = #"4.png";
break;
case 5:
strSprite = #"5.png";
break;
}
sprite = [CCSprite spriteWithFile:strSprite];
sprite.position = ccp(RandomX, 500);
sprite.scaleX = 40 / sprite.contentSize.width;
sprite.scaleY = 150 / winSize.height;
int posMinY = sprite.contentSize.width / 2;
int posMaxY = winSize.height - sprite.contentSize.height / 2;
int range = posMaxY - posMinY;
int actual = (arc4random()%range);
currentPos = actual;
[self addChild:baby];
int minDur = 2.0;
int maxDur = 5.0;
int rangeDur = maxDur - minDur;
int actualDur = (arc4random()%rangeDur) + minDur;
id drop = [CCMoveTo actionWithDuration:actualDur position:ccp(actual, -sprite.contentSize.height/2)];
id dropDone = [CCCallFuncN actionWithTarget:self selector:#selector(spriteDropDone:)];
[sprite runAction:[CCSequence actions:drop, dropDone, nil]];
sprite.tag = 1;
[sprites addObject: sprites];
}
//This is the method that schedules the drop
-(void)scheduleDrop:(ccTime)dt
{
[self spriteDrop];}
I hope there's somebody who would be able to help me with this.

Answer 1

Not sure if you want the number of sprites being dropped to change or the type (visually) to change over time.
One solution would be to have an ivar _numberOfSpritesToBeDropped. This could be increased in a method controlled by a scheduler at the requested time interval (e.g. 20 seconds). You'd then simply use this ivar in the method controlling the dispersing of the sprites...
If you simply want to add different kind of sprites every 20th. seconds you would simply change the random statement to
switch(arc4random() % _numberOfSpritesToBeDropped)...
Side note: your spriteDrop method seems to be doing more than simply dropping the sprites and it would certainly warrant to be split into two different methods.
Based on our discussion below, something like this perhaps:
NSInteger _maximumCurrentNumberOfSpritesAllowed;
-(id) init{
self = [super init];
if(self) {
[self setup];
}
return self;
}
-(void) setup{
self.isTouchEnabled = YES;
sprites = [[NSMutableArray alloc]init];
_maximumCurrentNumberOfSpritesAllowed = 1;
[self schedule:#selector(scheduleDrop:)interval:2.0];
}
-(void)spriteDrop{
if (sprites.count < _maximumCurrentNumberOfSpritesAllowed) {
CGSize winSize = [[CCDirector sharedDirector]winSize];
NSString *spriteName = [self randomSpriteName]; // I'd consider doing something similar with the position etc. as well
sprite = [CCSprite spriteWithFile:spriteName];
int RandomX = (arc4random() % 200);
sprite.position = ccp(RandomX, 500);
sprite.scaleX = 40 / sprite.contentSize.width;
sprite.scaleY = 150 / winSize.height;
int posMinY = sprite.contentSize.width / 2;
int posMaxY = winSize.height - sprite.contentSize.height / 2;
int range = posMaxY - posMinY;
int actual = (arc4random()%range);
currentPos = actual;
[self addChild:baby];
int minDur = 2.0;
int maxDur = 5.0;
int rangeDur = maxDur - minDur;
int actualDur = (arc4random()%rangeDur) + minDur;
id drop = [CCMoveTo actionWithDuration:actualDur position:ccp(actual, -sprite.contentSize.height/2)];
id dropDone = [CCCallFuncN actionWithTarget:self selector:#selector(spriteDropDone:)];
[sprite runAction:[CCSequence actions:drop, dropDone, nil]];
sprite.tag = 1;
[sprites addObject: sprites];
}
}
-(NSString *)randomSpriteName{
NSString *strSprite;
switch(arc4random() % 5){
case 1:
strSprite = #"1.png";
break;
case 2:
strSprite = #"2.png";
break;
case 3:
strSprite = #"3.png";
break;
case 4:
strSprite = #"4.png";
break;
case 5:
strSprite = #"5.png";
break;
default:
strSprite = #"1.png";
break;
}
return strSprite;
}
// Call this method with a scheduler at whatever interval you'd like
-(void) increaseMaximumNumberOfSpritesAllowed{
_maximumCurrentNumberOfSpritesAllowed++;
}
//This is the method that schedules the drop
-(void)scheduleDrop:(ccTime)dt{
[self spriteDrop];
}