How to hide and unhide an image in iOS? - ios

- (IBAction)press:(id)sender {
UIImage *bomb = [UIImage imageNamed:#"bom"];
UIImageView *bom =[[UIImageView alloc] initWithImage:bomb];
[bom setFrame: CGRectMake(83,115,35,35)];
[self.view addSubview:bom];
[UIView animateWithDuration:0.5 delay:0 options:UIViewAnimationCurveEaseIn animations:^{
[bom setFrame:CGRectMake(149,47,35,35)];
}
completion:^(BOOL finished)
{
[bom setFrame:CGRectMake(134,40,60,55)];
[bom setImage:[UIImage imageNamed:#"splash"]];
hits++;
_hit.text=[NSString stringWithFormat:#"%i",hits];
}];
}
Here is my code! The object bom here handles the imageview for splash.png image and i want that image to be appeared only for 0.5 sec when each time the button is pressed

You could set up an NSTimer that calls a method which hides the image. You would have to keep a reference to the bomb.
[NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:#selector(hideImage) userInfo:nil repeats:NO];
-(void)hideImage {
self.bomb.hidden = YES;
}

Related

Program multiple animations for single UIImageView with image change

I need to animate a UIImageView inside my application, and cyclically change the UIImage inside it, making it look like an animated photo slideshow.
Right now I'm using an NSTimer to fire every N seconds the UIImage change and the animation itself:
- (void)viewDidLoad {
// NSArray initialization
NSTimer *timer = [NSTimer timerWithTimeInterval:16
target:self
selector:#selector(onTimer)
userInfo:nil
repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
[timer fire];
[super viewDidLoad];
}
This is the onTimer selector code:
- (void) onTimer {
// cycle through max 9 images
if(imageIndex > 8)
imageIndex = 0;
// set the image
[_imageContainer setImage:[images objectAtIndex:imageIndex]];
// reset width and height of the UIImage frame
CGRect frame = [_imageContainer frame];
frame.size.width -= 170.0f;
frame.size.height -= 100.0f;
[_imageContainer setFrame:frame];
// fade in
[UIView animateKeyframesWithDuration:2.0f delay:0.0f options:0 animations:^{
[_imageContainer setAlpha:1];
} completion:^(BOOL finished) {
// image movement
[UIView animateKeyframesWithDuration:12.0f delay:0.0f options:0 animations:^{
CGRect frame = [_imageContainer frame];
frame.size.width += 170.0f;
frame.size.height += 100.0f;
[_imageContainer setFrame:frame];
} completion:^(BOOL finished) {
// fade out
[UIView animateKeyframesWithDuration:2.0f delay:0.0f options:0 animations:^{
[_imageContainer setAlpha:0];
} completion:nil];
}];
}];
imageIndex++;
}
This seem a very raw but "working" way to achieve what I want but I recognize it might not be the ideal way.
Is there any better method to achieve what I'm looking for?
Updated Answer For Fade Animation
- (void)viewDidLoad
{
[super viewDidLoad];
// self.animationImages is your Image Array
self.animationImages = #[[UIImage imageNamed:#"Image1"], [UIImage imageNamed:#"Image2"]];
// make the first call
[self animateImages];
}
- (void)animateImages
{
static int count = 0;
UIImage *image = [self.animationImages objectAtIndex:(count % [animationImages count])];
[UIView transitionWithView:self.animationImageView
duration:1.0f // animation duration
options:UIViewAnimationOptionTransitionCrossDissolve
animations:^{
self.animationImageView.image = image; // change to other image
} completion:^(BOOL finished) {
[self animateImages]; // once finished, repeat again
count++; // this is to keep the reference of which image should be loaded next
}];
}

iOS: Changing a UIImageView by pressing an UIButton

I'm making a very simple game. I have a UIButton and an UIImageView. What I'm trying to do is that when the user presses the button, it will change the image to another image and then back to the original image, to simulate an animation (Character moving)
I have this code:
file.m
{
IBOutlet UIImageView *image1;
IBOutlet UIButton *button;
}
-(IBAction)button:(id)sender;
file.h
-(IBAction)button:(id)sender{
[UIView animateWithDuration:1.0f
animations:^{
image1.alpha = 0.1f;
} completion:^(BOOL finished) {
image1.image = [UIImage imageNamed:#"image2.png"];
[UIView animateWithDuration:0.2f
animations:^{
image1.alpha = 1.0f;
} completion:^ (BOOL finished) {
image1.image = [UIImage imageNamed:#"image1.png"];
}];
}];
}
When I open the iOS simulator and press the button, the image dissolves, then reappears and then does the animation. The problem is that I don't want it to dissolve, I just want to show the animation. How do I prevent this from happening? Is it because I'm using alpha properties?
Thank you!
I used the following code to do what I think is what you need (shown here: https://www.dropbox.com/s/vtcyw0n257tgihx/fade.mov?dl=0):
- (void)viewDidLoad {
[super viewDidLoad];
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAction target:self action:#selector(test)];
iv = [[UIImageView alloc] initWithFrame:CGRectMake(100, 100, 150, 150)];
iv.image = [UIImage imageNamed:#"red"];
[self.view addSubview:iv];
}
- (void)test {
[UIView animateWithDuration:1.0f animations:^{
iv.alpha = 0.0f;
} completion:^(BOOL finished) {
iv.image = [UIImage imageNamed:#"blue"];
[UIView animateWithDuration:1.0f animations:^{
iv.alpha = 1.0f;
} completion:^ (BOOL finished) {
[UIView animateWithDuration:1.0f animations:^{
iv.alpha = 0.0f;
} completion:^ (BOOL finished) {
iv.image = [UIImage imageNamed:#"red"];
[UIView animateWithDuration:1.0f animations:^{
iv.alpha = 1.0f;
} completion:nil];
}];
}];
}];
}
You need to break it down into four parts. First you need to fade the original image out, change it to the second image, fade the second image in, fade the second image out, change back to the original image, then fade it back in.

Getting Timer error

After creating an image at a random location (spawnGood), if that object collides with the user controlled image (userToken) an NSTimer should start to work which uses the 'stick' method. This method is supposed to move spawnGood to the same position as userToken if userToken is moved (eg. sticks itself to userToken). However, I get the 'unrecognised selector sent to instance' error when the two images collide. It may either be a problem with the timer or the method, so is anyone able to suggest a solution to this? Thanks in advance :)
The code below produces the described error:
-(void)spawn{
spawn = [NSTimer scheduledTimerWithTimeInterval:2.0f
target:self
selector:#selector(spawnMechanism)
userInfo:nil
repeats:YES];
}
-(void)stick:(UIImageView *)spawnGood{
[UIView animateWithDuration:3.0
delay: 0
options: UIViewAnimationOptionCurveLinear
animations:^{
spawnGood.center=CGPointMake(userToken.center.x, userToken.center.y);
}
completion:^(BOOL finished){
NSLog(#"complete");
}];
}
-(void)spawnMechanism{
timeSinceLastSpawn++;
if(timeSinceLastSpawn >= 3)
{
if( arc4random() % 10 < 7 ){
UIImageView *spawnGood;
spawnGood=[[UIImageView alloc]initWithFrame:CGRectMake(arc4random() % 700, -100, 70,70)];
UIImage *image;
image=[UIImage imageNamed:#"friendly-01"];
[spawnGood setImage:image];
[array addObject:spawnGood];
[self.view addSubview:spawnGood];
NSLog(#"spawnGood spawned");
[UIView animateWithDuration:2.0
delay: 0.0
options: UIViewAnimationOptionCurveLinear
animations:^{
CGRect frame1 =[spawnGood frame];
frame1.origin.y =frame1.origin.y+950;
[spawnGood setFrame:frame1];
}
completion:^(BOOL finished){
if(CGRectIntersectsRect(userToken.frame, spawnGood.frame)){
NSLog(#"Good Collision");
stick=[NSTimer scheduledTimerWithTimeInterval:rate
target:stick
selector:#selector(stick:)
userInfo:nil
repeats:YES];
}else{
[UIView animateWithDuration:2.0 delay:0.0 options:UIViewAnimationOptionCurveLinear animations:^{
CGRect frame1 =[spawnGood frame];
frame1.origin.y =frame1.origin.y+950;
[spawnGood setFrame:frame1];
}
completion:nil];
};
}
];
}
}
}
You have two errors:
the target in this line
stick=[NSTimer scheduledTimerWithTimeInterval:rate
target:stick
selector:#selector(stick:)
userInfo:nil
repeats:YES];
should be 'self', not 'stick' (which is presumably an NSTimer * class variable?)
the parameter of stick should be an NSTimer *, not an image view.
You should prettify your code and add more context.

iOS set UIImage with animation

I'm trying to set the image of an UIImageView with an alternative image.
I know I can do [imageView setImage: image]. However, is it possible to add any dissolve effect(animation) when I change image?
I have done this earlier and here is the piece of code that helps you out.This code works fine for the issue you described above.
-(void)changeImage
{
myImageView.animationImages=[NSArray arrayWithArray:self.yourImageArray];
myImageView.animationDuration=10.0;
myImageView.animationRepeatCount=0;
[myImageView startAnimating];
myImageView.transform = CGAffineTransformMakeRotation(M_PI/2);
[self.view addSubview:myImageView];
//The timers time interval is the imageViews animation duration devided by the number of images in the animationImages array. 20/5 = 4
NSTimer *timer = [NSTimer timerWithTimeInterval:2.0
target:self
selector:#selector(onTimer)
userInfo:nil
repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
[timer fire];
}
//This will Fade in and fade Out Images.
-(void)onTimer{
[UIView animateWithDuration:2.0 animations:^{
myImageView.alpha = 0.0;
}];
[UIView animateWithDuration:0.5 animations:^{
myImageView.alpha = 1.0;
}];
}
If you want cross Dissolve you can use this UIViewAnimationOptionTransitionCrossDissolve.
Hope this will help you out if not please feel free ask.
You can use UIView's transitionWithView method for achieving this.
A sample code snippet:
UIImage * newImage= [UIImage imageNamed:#"newImg.png"];
[UIView transitionWithView:self.view
duration:3.0f
options:UIViewAnimationOptionTransitionCrossDissolve
animations:^{
yourImageView.image = newImage;
} completion:nil];
You can achieve this by using CAAnimation transitions
the effect you are looking for is called kCATransitionFade
Take a look here and here for some handy tutorials as well as the class reference.

iOS: UIImageView doesn't respond to tap gestures between animations

I have a multiple images to show in imageview using cross dissolve animation and taping on image displays detail about image. Following is the code working but tap on imageview is failing when it's animating from one image to another.
Code for attaching single tap gesture recogniser to UIImageview and starting animation timer.
self.imageView.userInteractionEnabled = YES;
self.singleTapGestureRecogniser = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(showDetails)];
self.singleTapGestureRecogniser.numberOfTapsRequired = 1;
self.singleTapGestureRecogniser.cancelsTouchesInView = NO;
[self.imageView addGestureRecognizer:self.singleTapGestureRecogniser];
[self startAnimationTimer];
- (void)startAnimationTimer
{
if(!self.timer && ![self.timer isValid]) {
self.timer = [NSTimer scheduledTimerWithTimeInterval:5.0
target:self
selector:#selector(startAnimation)
userInfo:nil
repeats:YES];
[self.timer fire];
}
}
Single tap on imageview works fine unless following code is executing! I have to tap 3-4 times to open details about image.
- (void)startAnimation
{
[UIView transitionWithView:self.imageView duration:2.0
options:UIViewAnimationOptionTransitionCrossDissolve
animations:^ {
currentImageIndex = ++currentImageIndex % self.images.count;
[self.imageView setImage:[[self.images objectAtIndex:currentImageIndex] image]];
} completion:^(BOOL finished) {
}
];
}
Could someone please suggest me how to get rid of this issue please.
set UIViewAnimationOptionAllowUserInteraction in the options like so
[UIView transitionWithView:self.imageView duration:2.0
options:UIViewAnimationOptionTransitionCrossDissolve | UIViewAnimationOptionAllowUserInteraction
animations:^ {
currentImageIndex = ++currentImageIndex % self.images.count;
[self.imageView setImage:[[self.images objectAtIndex:currentImageIndex] image]];
} completion:^(BOOL finished) {
}
];

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