How to Randomly Move Sprites and Keep Collisions Working - Cocos2d? - random

Question

I want to have a random sprite spawn and move across the screen.
I'm using CGRectIntersectsRect to detect collisions between the player and the randomly spawned sprites.
I've done this, the code works fine - when I have a set interval.
However, when I add randomness to the sprite's spawn times, collisions do not work all the time. Most collisions do not work at all.
I'm not sure what I'm doing wrong and would really appreciate any help in the right direction.
I think it has something to do with the schedule interval and how long it actually takes for the sprite to move across the screen.
Not sure though.
Also, if you could, I would also like to know the best way to remove enemySprite from the scene after it is off the screen?
Here's my code:
-(void)targetTimer {
[self schedule: #selector(enemySprite:) interval: 3.0f];
}
-(void)enemySprite:(id)sender {
CGSize winSize = [[CCDirector sharedDirector] winSize];
//SPAWN ENEYMY
enemySprite = [CCSprite spriteWithFile:#"eneymySprite.png"];
enemySprite.position = ccp (winSize.width/16, winSize.height/5);
[self addChild:enemySprite z:300];
CCAction *moveEnemyRight = [CCMoveTo actionWithDuration:3 position:ccp (winSize.width/1, winSize.height/5) ];
[enemySprite moveEnemyRight];
if ( enemySprite.position.y >= winSize.width ) {
//Best Way to Remove enemySprite from Scene?
}
NSLog(#"Collision");
[self unschedule:#selector(enemySprite:)];
unsigned int t = arc4random()%4 + 1;
[self schedule:#selector(enemySprite:) interval: t];
}

Answer 1

You have to craete an array of your enemies to be able to check if they leave game area (screen in your case). In your code this part
if ( enemySprite.position.y >= winSize.width ) {
//Best Way to Remove enemySprite from Scene?
}
will never be called. Because enemySprite.position.y >= winSize.width will be always NO as you just created this sprite and place it to the game area with coordinate
ccp(winSize.width/16, winSize.height/5)