I have been struggling with coding up a very simple app that launches and shows an image. The image is set programatically.
The steps I have tried:
Create empty application
Add ViewController & wire to AppDelegate
Add UIImageView
Set image.
I have code that doesn't work in a previous question:
Get UIImage to show in UIImageView
But that path did not work. If someone could outline the golden path of what I need to do I would be grateful.
#import "ViewControllerSimple.h"
#interface ViewControllerSimple ()
#end
#implementation ViewControllerSimple
- (void)viewDidLoad
{
[super viewDidLoad];
//Creat an image:
UIImage *image = [UIImage imageNamed: #"someImage.png"];
//Creat UIImageView:
UIImageView *imageView = [[UIImageView alloc]initWithImage:image];
//Set its frame:
[imageView setFrame:CGRectMake(0, 0, 300, 300)];
//Add to your view:
[self.view addSubview:imageView];
}
#end
Is this what your looking for? or the AppDelegate is the problum? or creating a UIViewController?
Related
I am building a simple application to show images.
I send the image url, and it should be downloading.
This is my code:
#import "ImageViewController.h"
#interface ImageViewController ()
#property (nonatomic, strong) UIImageView * imageView;
#property (nonatomic, strong) UIImage * image;
#end
#implementation ImageViewController
-(void)setImageURL:(NSURL *)imageURL{
_imageURL = imageURL;
self.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:imageURL]];
}
-(UIImageView*)imageView{
if(!_imageView)
return [[UIImageView alloc]init];
return _imageView;
}
-(UIImage*)image{
return self.imageView.image;
}
-(void)setImage:(UIImage *)image{
self.imageView.image = image;
[self.imageView sizeToFit];
}
-(void)viewDidLoad{
[self.view addSubview:self.imageView];
NSLog(#"Image Url = %#", self.imageURL);
}
#end
I call it like this:
if ([segue.destinationViewController isKindOfClass:[ImageViewController class]]){
ImageViewController* ivc = (ImageViewController*)segue.destinationViewController;
ivc.imageURL = [[NSURL alloc]initWithString:[NSString stringWithFormat:#"http://images.apple.com/v/iphone-5s/gallery/a/images/download/%#.jpg", segue.identifier]];
I am 100% sure that the passed url is correct because I already check that through debugging
The image is absolutely being downloaded because its size is large and the screen is blocking while downloading it.
The problem is the that imageView doesn't show it after finishing downloading.
Could u help me please?
Edit
The header file
#import <UIKit/UIKit.h>
#interface ImageViewController : UIViewController
#property(nonatomic, strong) NSURL* imageURL;
#end
This is all my code, so you can test it if you want.
Edit2
I have a scroll view, maybe that is the problem ?
Please check the image
You have an issue in the getter of the imageView property. You are not initialising the attribute, but returning a different object each time. Replace the line:
return [[UIImageView alloc]init];
by
_imageView = [[UIImageView alloc]init];
Please try to edit your code as following it is working for me, in your case problem may be because you are passing url from different view controller that you are :
[self.imageView setImage:[UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:#"http://images.apple.com/v/iphone-5s/gallery/a/images/download/photo_1.jpg"]]]];
You can check from attached screen shot..
Set the imageView's frame instead of sending sizeToFit method.
-(void)setImage:(UIImage *)image{
self.imageView.image = image;
// [self.imageView sizeToFit];
self.imageView.frame = CGRectMake(100.0, 100.0, image.size.width, image.size.height) ;
}
Edit :
I see there is a scrollView on 'self.view', so it may block self.imageView, try to bring it to front using [self.view bringSubviewToFront:self.imageView] ; if you want it be the topmost of all subView on self.view.
You are not assigning you newly created imageView to your _imageView. So every time it triggers imageView method, it returns a new UIImageView. try this...
- (UIImageView*)imageView
{
if(!_imageView) {
_imageView = [[UIImageView alloc]init];
return _imageView;
}
return _imageView;
}
I am working on a view based app, I have set the background image as follows.
.h file:
UIImageView *BackgroundImage;
.m file:
viewdidLoad method:
BackgroundImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"BG.png"]];
[[self view] addSubview:BackgroundImage];
[BackgroundImage.superview sendSubviewToBack:BackgroundImage];
and on the rotate method:
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
BackgroundImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"BG2.png"]];
[[self view] addSubview:BackgroundImage];
[BackgroundImage.superview sendSubviewToBack:BackgroundImage];
[super viewDidLoad];
}
Using this code I am able to set the background, but on rotation the first loaded image is not removed and the second one is loading just behind the first one, so just half of the image is visible, because of the first image is in front of second one.
Is there is a better way to do this?
OR
How can I just remove the first image and then set the second one?
Please help me to resolve this.
Change your didRotate... method to:
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
[BackgroundImage removeFromSuperview];
BackgroundImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"BG2.png"]];
[[self view] addSubview:BackgroundImage];
}
Notice the [BackgroundImage removeFromSuperview]; line. What we are doing here is whenever the device rotates, you remove the old image view and add another one.
Also please notice that variable names should start with lower case, so BackgroundImage should be backgroundImage. This is to tell them apart from classes' names.
If you change your code like this should to work
BackgroundImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"BG.png"]];
[self.view addSubview:BackgroundImage];
[self.view sendSubviewToBack:BackgroundImage];
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
[BackgroundImage removeFromSuperview];
BackgroundImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"BG2.png"]];
[self.view addSubview:BackgroundImage];
[self.view sendSubviewToBack:BackgroundImage];
[super viewDidLoad];
}
This is because you are initializing the UIImageview again. Better to use same UIImageView that is backgroundImage with different image.
[Background Image set image:[UIImage imageNamed:#"BG2.png"]];
Just set the new image when rotating:
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
BackgroundImage.image = [UIImage imageNamed:#"BG2.png"];
}
Your code kept adding new image views when rotating.
How [do stuff] properly in iOS?
Start your ivar names using an underscore and a lowercase letter: _backgroundImage instead of BackgroundImage.
Insert a subview in the right spot: [self.view insertSubview:_backgroundImage atIndex:0];
I have three images that I want to rotate in the background. Below is what I have so far. I want to have a class where I can hold all these UIImageViews and display them randomly in the background. I read about UIView and the frame method but I have no idea how to add them since it only takes in one frame.
Thus, I used NSArray to hold all the objects instead. The only problem now is when a new background appears, the old background doesn't disappear. Now do I remove the old background?
It would be great if someone can point me in the right direction.
Thanks!
#interface ViewController : UIViewController
#property (strong, nonatomic) NSArray *imageArray;
#property (strong, nonatomic) UIImageView *imageView;
- (IBAction)buttonPressed:(UIButton *)sender;
#end
// .m file
#implementation ViewController
#synthesize imageArray;
#synthesize imageView;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
imageView = [[UIImageView alloc] init];
UIImage *image1 = [UIImage imageNamed:#"image1.png"];
UIImage *image2 = [UIImage imageNamed:#"image2.png"];
UIImage *image3 = [UIImage imageNamed:#"image3.png"];
imageArray = [[NSArray alloc] initWithObjects:image1, image2, image3, nil];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)buttonPressed:(UIButton *)sender {
NSUInteger index = arc4random_uniform(self.imageArray.count);
[imageView setImage:[imageArray objectAtIndex:index]];
}
#end
This:
[self.view insertSubview:current atIndex:0];
Is adding another view to your view hierarchy, but you are not removing the one you previously placed. So you have an ever-growing stack of UIVews. You are also placing the new view at the bottom of the stack.
try
[[[self.view subviews] objectAtIndex:[[self.view subviews] count]-1] removeFromSuperview];
[self.view addSubview:current];
Or better - as #Kaan suggests - have a single UIImageView and simply change it's UIImage property.
To do this, your array will contain your UIImages not your UIImageviews.
Your UIView can be an UIImageview, or it can contain a UIImageview.
The UIImageview has an image property which you can set.
Your code would look something like this...
self.imageArray = [[NSArray alloc] initWithObjects:image1, image2, image3, nil];
NSUInteger index = arc4random_uniform(self.imageArray.count);
UIImage *current;
current = [self.imageArray objectAtIndex:index];
self.imageview.image = current;
In your approach, you have created 6 objects - 3 UIImages and 3 UIImageViews.
What you want can be accomplished using 4 objects instead of 6, using less memory, making your app run more quickly and answering your question at the same time (also, i'm assuming you have background images of all the same size, the size of the device's screen).
I would suggest creating first, only one UIImageView:
//backgroundImage is an IVAR
backgroundImage = [[UIImageView alloc] init];
followed by three UIImages and place them in an NSArray:
UIImage *image1 = [UIImage imageNamed:#"image1.png"];
UIImage *image2 = [UIImage imageNamed:#"image2.png"];
UIImage *image3 = [UIImage imageNamed:#"image3.png"];
//imagesArray is an IVAR
imagesArray = [[NSArray alloc]] initWithObjects: image1, image2, image3, nil];
Finally, to change the background, call the random function and update the UIImageView image property instead of popping a different view on top of the view stack:
NSUInteger index = arc4random() % [imagesArray count];
[backgroundImage setImage:[imagesArray objectAtIndex:index]];
I want to get the UIImage out of CGContextRef, and show it on UIImageView in a different UIViewController
So for this, I have written this code, I m writing this code, when I close my drawingview, because I have made my drawing view as a subview of UIViewController
//mydrawingView.m
- (void)closeButtonClicked
{
UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO,0.0);
[self.layer renderInContext:UIGraphicsGetCurrentContext()];
m_curImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
ViewController *table = [[ViewController alloc] init];
[table setImage:m_curImage];
[table viewDidLoad];
}
///myViewController.h
#interface ViewController : UIViewController
{
IBOutlet UIImageView *m_imageView;
UIImage *image;
}
#property(nonatomic, strong) UIImage *image;
///myViewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
m_imageView.image = image;
NSLog(#"%#", m_imageView.image);
}
But I am not able to show this image on UIImageview,
Regards
Ranjit
I have sorted out the answer for this question, to get the image out of the canvas , the above code applies and to show it on a imageView of anotherViewController, we have to implement delegate protocol method.
Regards
Ranjit
i have 3 navigation controller and i want to change each background using different image. I was implement a category that extends UINavigationBar like this :
- (void)drawRect:(CGRect)rect {
UIImage *image = [UIImage imageNamed:#"background.png"];
[image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];}
#end
but it make every navigation bar have a same background image. And then i try to implement code like this :
- (void)viewDidLoad {
[super viewDidLoad];
self.navigationController.navigationBar.tintColor = [UIColor blackColor];
UIImageView *backGroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"background.png"]];
[self.navigationController.navigationBar insertSubview:backGroundView atIndex:0];
[backGroundView release];
}
in every controller but each background just show the tintColor, not the image...what should I do???
and how if i want to do that too in tabbarController??
On each of your views, implement the following in your viewWillAppear: method
#import <QuartzCore/QuartzCore.h>
...
- (void)viewWillAppear:(BOOL)animated
{
self.navigationController.navigationBar.layer.contents = (id)[UIImage imageNamed:#"yourImageBgHere"].CGImage;
}
Cheers,
Rog