Rain / Snow falling how do you make it repeat?

[SeanyK]

Hey all,

I have created a basic rain falling type-animation;

However, when the objects falls to the bottom of the screen, it simply dissapears, how would I make this just repeat when it goes off the screen?

ie if you image it was an image of raindrops falling, I want it to then start again when it hits the bottom of the screen...

Hope this makes sense!

I currently use;

{
- (void)viewDidLoad
   
{
 moveObjectTimer = [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector (moveObject) userInfo:nil repeats:YES];

    [super viewDidLoad];
    
}

- (void) moveObject {    
   
    image.center = CGPointMake(image.center.x, image.center.y +5); 
    
}

[mediaspree]

psuedo code:

- (void) moveObject {

image.center = CGPointMake(image.center.x, image.center.y +5);

if (image.center.y > someYvalue) {
image.center.y=0;

}

}

[leormagal]

You should check the frame origin x and y. If the values are greater than you screen size, set them zero.

if (image.frame.origin.x > self.view.frame.size.width) {
CCGRect rect = image.frame;
rect.origin.x = 0.0f;
image.frame = rect;
}

if (image.frame.origin.y > self.view.frame.size.heigth) {
CCGRect rect = image.frame;
rect.origin.y = 0.0f;
image.frame = rect;
}

To do the animations, I would use the code bellow:

while(should_continue_animating) {
[UIView animateWithDuration:0.1 
                              delay:0.0 
                            options:(UIViewAnimationOptionAllowUserInteraction|UIViewAnimationOptionCurveLinear) animations:^{ 
                                
                                image.center = CGPointMake(image.center.x, image.center.y +5);
                                
                                ;}
                         completion:^(BOOL finished)
         { 

if (image.frame.origin.x > self.view.frame.size.width) {
CCGRect rect = image.frame;
rect.origin.x = 0.0f;
image.frame = rect;
}

if (image.frame.origin.y > self.view.frame.size.heigth) {
CCGRect rect = image.frame;
rect.origin.y = 0.0f;
image.frame = rect;
}
}];
}

[SeanyK]

Leor, that works absolutely perfectly,

Thank you so much for your help.

[Duncan C]

Originally Posted by SeanyK

Leor, that works absolutely perfectly,

Thank you so much for your help.

The approach the other posters have outlined is good, as far as it goes.

However, you should not do animation the way you are doing it.

You should use core animation to set up an animation that moves your snowflakes from the top to the bottom of the screen in 1 step. The system will take care of animating the motion. It will be smoother than moving the views yourself, it will be less prone to problems if your program gets busy doing something else, and it will put a MUCH smaller load on the system, because it uses the graphics hardware to do the animation, and it uses highly optimized system frameworks to do the animation.

Take a look at the UIView animation class methods who's names start with animateWithDuration.

You probably want animateWithDuration:delayptions:animations:compl etion:

That method will let you specify that you want linear animation (options = UIViewAnimationOptionCurveLinear) , and will also let you include a completion routine that will start the animation over once the objects reach the bottom of the screen.

[sandromandro]

Hey, I have a question, if i paste it in my project with my image names in my
-(void) moveObjekt.
i have an error: "Use of undeclared identifier 'should_continue_animation'"


please help me

[Duncan C]

Originally Posted by sandromandro

Hey, I have a question, if i paste it in my project with my image names in my
-(void) moveObjekt.
i have an error: "Use of undeclared identifier 'should_continue_animation'"


please help me

Post a new thread.

Include the relevant code. You're saying that you have a method moveObjekt, but did not show that code. It sounds like that method tries to use a boolean should_continue_animation, but we don't know what that is.

Again, create a new thread with your specific question and the background info we need to help you.

[sandromandro]

My code is:

- (void)viewDidLoad
{
ObjektTimer = [NSTimer scheduledTimerWithTimeInterval:0.035 target:self selector:@selector(movepicture) userInfo:nil repeats:YES];
[super viewDidLoad];
}

-(void) movepicture{
while (should_continue_animating) {
[UIView animateWithDuration:0.1
delay:0.1
optionsUIViewAnimationOptionAllowUserInteraction |UIViewAnimationOptionCurveLinear) animations:^{

Menueball.center = CGPointMake(Menueball.center.x, Menueball.center.y +1);

;}
completion:^(BOOL finished)
{

if (Menueball.frame.origin.x > self.view.frame.size.width) {
CGRect rect = Menueball.frame;
rect.origin.x = 0.0f;
Menueball.frame = rect;
}

if (Menueball.frame.origin.y > self.view.frame.size.height) {
CGRect rect = Menueball.frame;
rect.origin.y = 0.0f;
Menueball.frame = rect;
}
}
];
}
}

and i have an error with "should_continue_animating"
what can i do?
please help me
i'm searching for a code to repeat this falling image, since a week

[Duncan C]

Originally Posted by sandromandro

My code is:


and i have an error with "should_continue_animating"
what can i do?
please help me
i'm searching for a code to repeat this falling image, since a week

You can create a new thread.

And use code tags rather than quotes to include code.