I call this method in my ViewController, which contains a UIScrollView, when the user taps a button.
-(void) updateView:(NSURL *) urlPicture{
UIImageView *imageNews = [[UIImageView alloc]initWithFrame:CGRectMake(0,0,300,200)];
imageNews.contentMode = UIViewContentModeScaleAspectFit;
[imageNews setImageWithURL:urlPicture];
[self.scrollView addSubview:imageNews];
}
It seems to work fine, but when I got a strange behavior.
It doesn't clear the previous image to put the new one.
E.g: if the first image is 300x200 and the second one is 200x200 I still can see the sides of the first one when the app download the second.
I would like to know how to clear the previous image before download the second.
I already try imageNews.image = nil; but it didn't work
First you need to remove old view from scrollView. You can edit your code as mentioned below
#define IMAGE_VIEW_TAG 1001
-(void) updateView:(NSURL *) urlPicture{
UIView *oldView = [self.scrollView viewWithTag:IMAGE_VIEW_TAG];
if(oldView)
[oldView removeFromSuperView]
UIImageView *imageNews = [[UIImageView alloc]initWithFrame:CGRectMake(0,0,300,200)];
imageNews.tag = IMAGE_VIEW_TAG;
imageNews.contentMode = UIViewContentModeScaleAspectFit;
[imageNews setImageWithURL:urlPicture];
[self.scrollView addSubview:imageNews];
}
Well I am not really sure what your application does ,
but seems like you need to have only 1 image
so I would suggest you to remove the previous image.
There are 2 ways to do so:
1) you could use your image as property and simply call [_imageNews removeFromSuperView];
2) you can iterate through your self.scrollView's sub views and remove it from there.
Related
I intend to make a splash screen on iOS consists of a person, a chair objects. Each of these objects has seperated aspects like the hands, head, body and feets that animated together. I wonder which is better way to go? Importing a GIF file or coding CALayer objects then adding animation?
You can't use GIF files or any code for animation for your launchscreen (splash screen), you can only use a static image, a PNG or JPG (if the launchscreen is a storyboard).
So, if you want your app's startup with some animation then you should manage it in your first view controller.
You can animate imageview with image sets like,
UIImageView* myImageViewForAnimation = [[UIImageView alloc] initWithFrame:self.view.bounds];
myImageViewForAnimation.animationImages = [NSArray arrayWithObjects:
[UIImage imageNamed:#"image1"],
[UIImage imageNamed:#"image2"],
[UIImage imageNamed:#"image3"],
[UIImage imageNamed:#"image4"], nil];
myImageViewForAnimation.animationDuration = 1.0f;
myImageViewForAnimation.animationRepeatCount = 0;
[myImageViewForAnimation startAnimating];
[self.view addSubview: myImageViewForAnimation];
Update (as asked in comment) :
You can get your view on which you have added gesture recognizer in your action method or you can set tag to every imageview and handle it in action method.
For example,
-(void)tapOnProfileImage : (UITapGestureRecognizer*)recog{
UIImageView *tempView = (UIImageView *)recog.view;
// or
if (recog.view.tag == 1) {
// image 1
}
if (recog.view.tag == 2) {
//image 2
}
}
So, on every image view, you should add target with selector - tapOnProfileImage and you can differentiate it as mentioned in above code snippet!
You can use gif image but not directly on launch xib. You create one view controller and load gif image on that view controller, once animation is completed then remove this controller from navigation stack. https://github.com/Flipboard/FLAnimatedImage use this gif image view control.
Alright, so I have 5 custom images that I want in my game.
So each variable for example will have a value set with it, image 1 = 1, image 2 = 2, etc. I want the user to be able to press one of these images and when they do, it will change from say image 5 to image 4.
Do I need to put these images in an array/dictionary/etc? I honestly have no idea how to go about it so dont know what to search for on google.
Any help or advice is appreciated.
You should use imageViews and add a gesture recognizer to each imageView, and then give each imageView tags in order to organize them. You can set tags in storyboard by pressing the imageView and then entering the tag under the shield. Each imageView should have a distinct tag. I'm giving a programatic example below for clarity, though.
UITapGestureRecognizer * tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(wasTapped:)];
tap.delegate = self;
imageView.tag = 1;
[imageView addGestureRecognizer:tap];
When an imageView is tapped the selector will be called and you can change the imageView like so.
-(void) wasTapped:(UIGestureRecognizer *) recognizer
{
UIImageView * imageView = (UIImageView*) recognizer.view;
if (imageView.tag == 1){
// change image to something else
UIImage * newImage = [UIImage imageNamed:#"newImage"];
imageView.image = newImage;
}
}
You may have to call [imageView setNeedsDisplay] to make the new image appear. You also will have to devise some system to organize the imageViews. You may also have to set imageView.userInteractionEnabled to YES.
I have an app that has been working just fine for ages. I upgraded XCode and now 1 of my views is doing weird things.
None of the objects I attempt to add to the UIScrollview show up.
I have 2 screens that are basically identical in code (i literally copy and pasted). One of them works just fine, I click a button to move to the other screen, and it doesn't display ANY components I attempt to add to the scroll view.
Any ideas as to what could be wrong? Why it would suddenly stop adding components after upgrading Xcode?
I have a background image that I have tested and changed to self.view that changes just fine. But anything I try to add to my UIScrollView, nothing gets added. Some sample code...
my .h declaration
#interface OutgateInputViewController : UIViewController<UITextFieldDelegate,UIPickerViewDelegate>{
IBOutlet UIScrollView *outputsView;
a sample in my .m
UIGraphicsBeginImageContext(self.view.frame.size);
[[UIImage imageNamed:#"inputbackground.png"] drawInRect:self.view.bounds];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
self.view.backgroundColor = [UIColor colorWithPatternImage:image];
int x = 20;
int y = 20;
CGRect myImageRect = CGRectMake(0, 15, 320, 32.5);
UIImageView *myImage = [[UIImageView alloc] initWithFrame:myImageRect];
NSString *imgName = #"screen_logo.png";
[myImage setImage:[UIImage imageNamed:imgName]];
[outputsView addSubview:myImage];
y = y + 30;
pretty standard stuff. its an EXACT copy up to this point of the screen that works. (even a copy long after, i just pull data from a different location). So any ideas on what changed?
I went back and re-did everything from scratch, and apparently for some reason THIS View needs the additional __weak at the start of the declaration in the .h ...
no idea why as of yet, but this solved the issue of the entire view being broken.
__weak IBOutlet UIScrollView *outputsView;
I would like to obtain this effect (http://stackoverflow.com/questions/7023271/how-to-adjust-drop-shadow-dynamically-during-an-uiimageview-rotation) but from a more complex image than just a red square ! If the link ever gets broken, it's a about how to adjust drop shadow dynamically during an UIImageView rotation.
So I tried implementing something but I just can't get the shadow in a separate layer... Here is my code, very simple, but doesn't work:
// here is my code
- (void)viewDidLoad {
[super viewDidLoad];
testView = [[UIImageView alloc] initWithImage: [UIImage imageNamed:#"handNoShadow.png"]];
testViewShadow = [[UIView alloc] initWithFrame:testView.frame];
testViewShadow.layer.shadowPath = [[testView layer] shadowPath];
testViewShadow.layer.shadowOpacity = 1.0;
testViewShadow.layer.shadowOffset = CGSizeMake(10, 10);
testViewShadow.layer.shadowRadius = 5.0;
[self.view addSubview:testViewShadow];
[self.view addSubview:testView];
}
PS: i did #import
I do get an image but no shadow... =(
Any lead, help, code, link... is welcome !
Thanks
possible cause:
your testViewShadow.clipToBounds property is set to YES (should be NO)
your testViewShadow do the drawing of the shadow correctly but another UIView is on top and mask it. Check your Z order. Either the order in Storyboard/Nib file (or the order you added the subviews programmatically). Last in the list (or last one added) is on top. For my app I had to put the UIView that need a shadow last so that no other view mask it.
upon a tap, I want to let a few UIImageView objects appear on an underlaying UIView.
So I created the following action:
- (IBAction)startStars: (id) sender
{
UIView* that = (UIView*) sender; // an UIButton, invisible, but reacting to Touch Down events
int tag = that.tag;
UIView* page = [self getViewByTag:mPages index:tag]; // getting a page currently being viewed
if ( page != nil )
{
int i;
UIImage* image = [UIImage imageNamed:#"some.png"];
for ( i = 0 ; i < 10 ; ++i )
{
// create a new UIImageView at the position of the tapped UIView
UIImageView* zap = [[UIImageView alloc] initWithFrame:that.frame];
// assigning the UIImage
zap.image = image;
// make a modification to the position so we can see all instances
CGPoint start = that.layer.frame.origin;
start.x += i*20;
zap.layer.position = start;
[page addSubview:zap]; // add to the UIView
[zap setNeedsDisplay]; // please please redraw
[zap release]; // release, since page will retain zap
}
[image release];
}
}
Unfortunately, nothing shows up. The code gets called, the objects created, the image is loaded, even the properties are as expected.
Page itself is a real basic UIView, created with interface builder to contain other views and controls.
Still, nothing of this can be seen....
Has anyone an idea what I am doing wrong? Do I need to set the alpha property (or others)?
Thanks
Zuppa
A couple of things I would check:
Logging to make sure this section of code is actually being called.
Use the designated initializer for UIImageView:
[[UIImageView alloc] initWithImage:image];
This will ensure that your new view has the correct size for the image - what are the relative sizes of zap and your image? It could be out of the frame.
Ensure that the image actually exists and is created
Try not adjusting the layer properties, but setting the center of the image view instead. In fact, in the first instance don't adjust it at all and just see if you can see anything. I'm not sure but I think position might be moving the layer within the view so could be moving your image out of sight. Try:
CGPoint newCenter = that.frame.origin;
newCenter.y += zap.bounds.size.height/2;
newCenter.x += i*20;
zap.center = origin;
setNeedsDisplay is not required. Obviously from your comments it was an act of desparation!
Is your UIImage nil?
You don't need to have the .png extension for imageNamed: to work. It might not even work correctly if you put it in, I'm not sure. You're also overreleasing your image. imageNamed: returns an autoreleased image so there is no reason to call release on the image unless you're also calling retain on it somewhere.
I see a potential error: on second invocation you will re-add another copy, so take care about removing subviews before adding anew copy. Yu can alternatively move a previous view.
99% of my cases about non-visible views with images are wrong names, so as suggested, load using a temp var:
UIImage img = [UIImage imageNamed..];
and test img.