Unknown error in game (XCode) - ios

Question

I'm making my second game on XCode and there seems to be something wrong with the code. It's a space shooter game where the playership follows your finger and you tap to release the missile. The problem is... when I press 'start game', everything is hidden and will not popup. Here is my viewcontroller.h and viewcontroller.m
ViewController.m
#import "ViewController.h"
#interface ViewController ()
#end
int score;
int lives;
int enemyAttackOccurence;
int enemyPosition;
int randomSpeed;
float enemySpeed;
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
#implementation PlayViewController
-(void)viewDidAppear:(BOOL)animated {
// Images that are to be hidden
playerShip.hidden = YES;
enemyShip.hidden = YES;
missile.hidden = YES;
earth.hidden = YES;
// Hidden Labels
scoreLabel.hidden = YES;
livesLabel.hidden = YES;
// Set score and lives remaining
score = 0;
lives = 0;
// Strings
scoreString = [NSString stringWithFormat:#"Score: 0"];
liveString = [NSString stringWithFormat:#"Lives: 0"];
// Initial Label Text
scoreLabel.text = scoreString;
livesLabel.text = liveString;
// Image starting positions
playerShip.center = CGPointMake(150, 658);
enemyShip.center = CGPointMake(175, 20);
missile.center = CGPointMake(playerShip.center.x, playerShip.center.y);
}
-(IBAction)startGame:(id)sender {
// Hide buttons
startButton.hidden = YES;
exitButton.hidden = YES;
// Images to show
playerShip.hidden = NO;
enemyShip.hidden = NO;
earth.hidden = NO;
// Labels
scoreLabel.hidden = NO;
livesLabel.hidden = NO;
[self positionEnemy];
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
touch = [touches anyObject];
CGPoint point = [touch locationInView:self.view];
playerShip.center = CGPointMake(point.x, playerShip.center.y);
}
-(void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
[missileMovementTimer invalidate];
missile.hidden = NO;
missile.center = CGPointMake(playerShip.center.x, playerShip.center.y);
missileMovementTimer = [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:#selector(missileMovement) userInfo:nil repeats:YES];
}
-(void)positionEnemy {
// Random enemy position
enemyPosition = arc4random() % 249;
enemyPosition = enemyPosition + 20;
// Enemy Image Location
enemyShip.center = CGPointMake(enemyPosition, -40);
// Set enemy speed
randomSpeed = arc4random() % 3;
switch (randomSpeed) {
case 0:
enemySpeed = 0.03;
break;
case 1:
enemySpeed = 0.02;
break;
case 2:
enemySpeed = 0.01;
default:
break;
}
enemyAttackOccurence = arc4random() % 5;
[self performSelector:#selector(enemyMovementTimerMethod) withObject:nil afterDelay:enemyAttackOccurence];
}
-(void)enemyMovementTimerMethod {
enemyMovementTimer = [NSTimer scheduledTimerWithTimeInterval:enemySpeed target:self selector:#selector(enemyMovement) userInfo:nil repeats:YES];
}
-(void)enemyMovement {
enemyShip.center = CGPointMake(enemyShip.center.x, enemyShip.center.y + 2);
if (CGRectIntersectsRect(enemyShip.frame, earth.frame)) {
lives = lives - 1;
liveString = [NSString stringWithFormat:#"Lives: %i", lives];
livesLabel.text = liveString;
// Stop Enemy Moving
[enemyMovementTimer invalidate];
if (lives > 0) {
[self positionEnemy];
}
if (lives == 0) {
[self gameOver];
}
}
}
-(void)missileMovement {
missile.hidden = NO;
missile.center = CGPointMake(missile.center.x, missile.center.y - 2);
if (CGRectIntersectsRect(missile.frame, enemyShip.frame)) {
score = score + 1;
scoreString = [NSString stringWithFormat:#"Score: %i", score];
scoreLabel.text = scoreString;
// Stop missile
[missileMovementTimer invalidate];
// Position missile to be at the playerShip's center
missile.center = CGPointMake(playerShip.center.x, playerShip.center.y);
missile.hidden = YES;
// Stop enemy movement
[enemyMovementTimer invalidate];
[self positionEnemy];
}
}
-(void)gameOver {
[enemyMovementTimer invalidate];
[missileMovementTimer invalidate];
[self performSelector:#selector(gameReplay) withObject:nil afterDelay:3];
}
-(void) gameReplay {
// Images that are to be hidden
playerShip.hidden = YES;
enemyShip.hidden = YES;
missile.hidden = YES;
earth.hidden = YES;
// Hidden Labels
scoreLabel.hidden = YES;
livesLabel.hidden = YES;
// Set score and lives remaining
score = 0;
lives = 0;
// Strings
scoreString = [NSString stringWithFormat:#"Score: 0"];
liveString = [NSString stringWithFormat:#"Lives: 0"];
// Initial Label Text
scoreLabel.text = scoreString;
livesLabel.text = liveString;
// Image starting positions
playerShip.center = CGPointMake(150, 658);
enemyShip.center = CGPointMake(175, 20);
missile.center = CGPointMake(playerShip.center.x, playerShip.center.y);
}
#end
ViewController.h (Just for backup)
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController {
IBOutlet UIButton *startGame;
}
#end
#interface PlayViewController : UIViewController {
IBOutlet UIImageView *playerShip;
IBOutlet UIImageView *enemyShip;
IBOutlet UIImageView *missile;
IBOutlet UIImageView *earth;
IBOutlet UILabel *livesLabel;
IBOutlet UILabel *scoreLabel;
IBOutlet UIButton *startButton;
IBOutlet UIButton *exitButton;
UITouch *touch;
NSString *liveString;
NSString *scoreString;
NSTimer *enemyMovementTimer;
NSTimer *missileMovementTimer;
}
-(IBAction)startGame:(id)sender;
#end
I am watching a tutorial for this game, the person who created doesn't reply. Please help -- I cannot be any more specific. It just must be a weird gap in the code. Thanks.

Answer 1

Also, you have an IBOutlet and IBAction set for your StartGame button. The IBOutlet you never seem to use. You could be confusing your compiler by having the same name for the UIButton's IBOutlet and IBAction. Remove the IBOutlet, or change the name properly and see if that changes anything.

Answer 2

I'd recommend messing with your lines of code where you are setting object.hidden = YES and object.hidden = NO and see what happens. Often times tampering and testing your code is a good way to see what is going on. Make sure images are set for your UIImageViews. I'm assuming they are set in your interface builder because i don't see where you set them in your code. If there is no image set for the UIImageViews they will be see-through unless given a specific color. If tampering with the code doesn't work it won't hurt to re-watch the tutorial and make sure you didn't mess anything up. Often times the tutorials we watch are out-dated and we are left to solve a small problem ourselves and this may or may not be one of those instances. Again though, test your code and see if things are actually being set to hidden or not when you press that button.