CODEWITHSUNDEEP
objective-c
Chester Cordero
Chester Cordero

Reputation: 27

Alternative to "self" in calling methods in Objective-C

This may sound really noob, but i've spent an entire day wrestling with this problem and would appreciate some help.

You see i have a method which I call more than once inside gameplay. If I use [self myMethod]; then it works for ONE time. And then when I call it again, the animation in the method doesn't commence anymore.

What I need is to replace "self" with an alternative that can be "alloc'ed" and "released" to make my animations work.

I've tried;

@implementation gameViewController


gameViewController *object = [[gameViewController alloc] init];

[object myMethod];

However the above substitute for self doesn't even call on the method. I don't know what I did wrong, it's suppose to work just like "self".

Is there something i missed? How do you make an object of the class to work just like "self" does?

Thanks so much.

Here is a more detailed look of my code;

[self explosionAnimations];

- (void) explosionAnimations
{


      UIImage *image = [UIImage imageNamed: @"Yellow Explosion.png"];

      [bomb setImage:image];   

      [UIView beginAnimations:@"bomb1ExplosionIncrease" context:NULL];

      [UIView setAnimationDuration:0.5];

      [UIView setAnimationDelegate:self];

      bomb.transform = CGAffineTransformMakeScale(3.4, 3.4);

      [UIView commitAnimations];

}

The setImage works fine every time. But the animations stop working on the second call of the method. While in the console it logs "animation completed" with nothing happening to the image.

This leads me to believe that somehow "self" believes that the animation was already done and will not bother to do it again. So I thought a new "alloc" might give it a kick awake.

Upvotes: 0

Views: 264

Answers (1)

rdelmar
rdelmar

Reputation: 104092

The problem doesn't have anything to do with "self". The problem is that you set the transform in your animation, and then when you run it again, you're setting the same transform, so it does nothing. You need to reset the frame to the new frame and then set the transform back to the identity transform before you do the animation again. Also, you should be using block based animations. I'm not sure this is the best way to do it, but this worked for me (if you have auto layout turned off).

- (void)explosionAnimations {

    UIImage *image = [UIImage imageNamed: @"Yellow Explosion.png"];
    [self.bomb setImage:image];

    [UIView animateWithDuration:.5 animations:^{
        self.bomb.transform = CGAffineTransformMakeScale(3.4, 3.4);
    } completion:^(BOOL finished) {
        CGRect newFrame = self.bomb.frame;
        self.bomb.transform = CGAffineTransformIdentity;
        self.bomb.frame = newFrame;
    }];
}

If you're doing this in an app with auto layout turned on (which it is by default), then I would not use a transform, but just resize the width and height of the image view by adjusting its height and width constraints. So, in this method, you should make IBOutlets to height and width constraints you make in IB, then change their constant values in an animation block:

[UIView animateWithDuration:.5 animations:^{
        self.heightCon.constant = self.heightCon.constant * 3.4;
        self.widthCon.constant = self.widthCon.constant * 3.4;
        [self.view layoutIfNeeded];
    }];

Upvotes: 5

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