I designed a very simple interface for an ipad device: UIView + a navigation bar.
Then after the view is load, it will download an image from a location and use the following method to display it:
-(void)connectionDidFinishLoading:(NSURLConnection *)connection{
UIImage* testImg = [UIImage imageWithData:_networkData];
UIImageView* testView = [[UIImageView alloc] initWithImage:testImg];
[_view addSubview:testView];
[testView release];
}
The problem is now the new UIImage occupies the whole visible area of the Ipad.
I wonder how can I fix this issue? I suppose I have to find out the frame of the display area in the original view, and then assign it to the UIImageView instance?
initWithImage will automatically adjust the frame to match the size of the image you're passing in. To tell the UIImageView to take the same size as its parent view you could just add the following line before you add the subview:
testView.frame = _view.bounds
...we use bounds rather than frame because the superview may have an offset that we don't want the image view to have.
Related
Im a beginner in programing iOS, so I have 2 questions:
1- I have a UIViewcontroller which load a few uiview and user is able to move them via touch. Now I want to put an image background in this way:
UIImageView *backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"board.png"]];
[self.view addSubview:backgroundView];
But the image covers over all uivews!!
2- As I said, I move my uiviews by touch and when they have collided in the end touch they both goes in a folder, and a folder is created. So I want to know how I can make that a special image shows on the created folder ??
if (view != toMove && CGRectContainsPoint(view.frame,toMove.center)) {
viewToBefolder = view;
}
You can add your background view first, and then the rest of the views you add will be on top, or just do this:
[self.view sendSubviewToBack:backgroundView];
If your image view is covering the the background, you should be setting the size and position of the image view, or setting the constraints so that it is added at the size and position that you want.
Set your imageview into the main window.
UIImageView *backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"background.png"]];
[self.window addSubview:backgroundView];
[self.window sendSubviewToBack:backgroundView];
Then set all your view controller view clear color. so, By default it's always display background image view into the all view.
I have an app which requires dynamic background images (they are set server side) - the views used are both UIViewControllers and UITableViewControllers, so I have created classes which extend both controller type and add a background image to each view on load.
All works fine apart from the background image is refusing to stretch on an iPad on the UIViewController only - I am using Xcassets and have the standard and #2x retina images applied - all works fine on iPhone - and on both for UITableViewControllers but the UIViewController class doesn't appear to stretch the background on an iPad - it simply displays the image in the top left corner at the standard 320 width size.
This is my code - can anyone suggest where I am going wrong?
UIImageView *backgroundImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed: [self.prefs stringForKey:#"BGImageBlur"]]];
backgroundImage.contentMode = UIViewContentModeScaleToFill;
[self.view addSubview:backgroundImage];
[self.view sendSubviewToBack:backgroundImage];
You're creating a UIImageView and providing it the image to set within the view. This will create the UIImageView with the frame of the given Image. You must first specify the frame, then set the image. Try this:
UIImageView *backgroundImage = [[UIImageView alloc] initWithFrame:self.view.bounds];
backgroundImage.image = [UIImage imageNamed:[self.prefs stringForKey:#"BGImageBlur"]]
This will create an ImageView that is the same size as its parent. If this is not what you want you'll probably have to specify some other layout constraints.
I have written some code which applies and image to a view for a UIViewController. The code is supposed to be iPhone screensize independent in as far as the difference in height between the iPhone 4 and 5.
self.view.autoresizingMask = UIViewAutoresizingFlexibleHeight;
self.view.clipsToBounds = YES;
UIGraphicsBeginImageContext(self.view.frame.size);
[[UIImage imageNamed:#"myimage.png"] drawInRect:self.view.bounds];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIView *imageView = [[UIView alloc] initWithFrame:CGRectMake(0,0, self.view.frame.size.width, self.view.frame.size.height)];
imageView.backgroundColor = [UIColor colorWithPatternImage:image];
[self.view addSubview: imageView];
image = nil;
imageView = nil;
I found that when I add this code to the viewDidLoad method, the code failed to detect the different window size. However when I place it in viewWillAppear, the code does correct work with both screen sizes. I don't understand why.
Does any one know why this would happen ? I would like to understand it.
thanks
This happens because at the time the view is loaded, its' content hasn't necessarily been laid out and the size isn't known. This is especially true when using the autolayout system. The basic steps are,
The view is loaded
The view is laid out by the system using the constraints you give in the storyboard or code
The view appears
So the most appropriate place to put this appears to be viewDidLayoutSubviews. At that point the view and its subviews have been laid out, and the sizes are there. But putting it in viewWillAppear (or viewDidAppear, for that matter) will work, albeit will be less correct.
viewDidLoad method is called when the view controller's root view just has been created. At this point it is not added to the window hierarchy and auto layout has not been done. That is why you see this behavior.
This being said why draw the image in the graphic context? Just use UIImageView to display the image.
What you are doing is almost correct. As others have stated, in viewDidLoad the final size of the view controller's view is not set yet. The proper solution is to set the subview's autoresizingMask properly.
UIView *imageView = [[UIView alloc] initWithFrame:CGRectMake(0,0, self.view.frame.size.width, self.view.frame.size.height)];
imageView.backgroundColor = [UIColor colorWithPatternImage:image];
imageView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
[self.view addSubview: imageView];
This assumes you want the image view to fill the view controller's view.
Another solution is to update the frames of the subviews in the viewWillLayoutSubviews method.
I have set up a launch image and this shows correctly when the app starts. In the initial view controller I do this in the viewDidLoad:
[self.imageBackground setImage:[UIImage imageNamed:#"Default.png"]];
Default.png is the same image as the launch image. Why does the image snaps (the image gets resized in the initial view controller) and how can I prevent this?
Thanks in advance
Try this.
UIImageView *backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"Default.png"]];
[self.view addSubview:backgroundView];
Add backgroundView.frame if you are facing any problem.
Its is based on your image view size in view controller. lets set image view size same as view size in view controller. It will reflect the same size.
I have a XIB file with UIControl and UIScrollView elements inside of it. I would like to add a background image to the view. I tried adding an ImageView in IB but I could not get it to be present as a background and it obscured the control elements. Sending a sendViewBack message doesn't seem to do anything either.
When I create a UIImageView programmatically, it doesn't show up.
Below is the code I attempted:
Programmatic Creation
UIImage *imageBackground = [UIImage imageWithContentsOfFile:#"globalbackground"];
UIImageView *backgroundView = [[UIImageView alloc] initWithImage:imageBackground];
[[self view] addSubview:backgroundView];
[[self view] sendSubviewToBack:backgroundView];
Dealing with the NIB file
[[self view] sendSubviewToBack:background];
where background is an IBOutlet declared in the header file and connected to the NIB's image view in IB.
Is there a step I'm missing here?
Set the frame and dont use sendSubviewToBack:. If you are working with UIImageViews you have to use [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"imageName.png"]];
UIImageView *backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"imageBackground"]];
backgroundView.frame = self.view.bounds;
[[self view] addSubview:backgroundView];
hope this was the deal.
Don't add the image view as a subview of the scroll view, it needs to be a separate view at the top level of the hierarchy, then sent to the back of the Z-order.
You will need to set the background of your scroll view to [UIColor clearColor], and ensure that the scroll view is not marked as opaque. You can do this in code or in interface builder.
Don't use imageWithContentsOfFile and then just pass it a filename with no extension (I'm assuming .png) - this is probably returning nil. Use imageNamed: instead (you don't supply an extension in that case, iOS4 and above)
Depending on the nature of your image, you can also generate a colour with it and use that as the background colour of your scroll view. I'm assuming self.view is the scroll view:
self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"globalBackground"]];