I have a UIScrollView with an image inside it. This is the code:
- (void)viewDidLoad {
[super viewDidLoad];
UIImageView *imView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:imageName]];
UIScrollView *imScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 96)];
[imScrollView addSubview:imView];
[imScrollView setContentSize:CGSizeMake(530, 96)];
[[self view] addSubview:imScrollView];
[imView release];
[imScrollView release];
}
This is what it looks like in portrait mode:
I want to know
1. How can I position the image exactly in the middle of the screen (horizontally).
2. How can I make sure this is going to be the same if the orientation switches to landscape. This is what currently the landscape looks like :
Thanks.
Try setting the autoresizingMask property of your imView just after you create it:
imView.autoresizingMask = UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleLeftMargin;
The UIView class reference contains more info.
Related
According to this question, the UIGestureRecognizer has a view property which refers to the view the gesture is attached to. I used this in my code like this:
//Code for the 1st UIScrollView
UIImageView *bookCover = [[UIImageView alloc]initWithFrame:CGRectMake(50, 100, 145, 420)];
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc]initWithTarget:self
action:#selector(downloadBookTapped:)];
[bookCover addGestureRecognizer:singleTap];
[bookCover release];
[singleTap release];
//Code for the second UIScrollView
UIImageView *fileCover = [[UIImageView alloc]initWithFrame:CGRectMake(50, 100, 145, 420)];
UITapGestureRecognizer *singleFileTap = [[UITapGestureRecognizer alloc]initWithTarget:self
action:#selector(downloadFileTapped:)];
[fileCover addGestureRecognizer:singleFileTap];
[fileCover release];
[singleFileTap release];
And here is where I user the view property:
- (void)downloadBookTapped:(UITapGestureRecognizer *)sender
{
UIImageView *imgView = (UIImageView *)sender.view;
CGRect rect = [imgView frame];
UIImageView *images = [[UIImageView alloc]initWithFrame:rect];
//rest of code here...
}
- (void)downloadFileTapped:(UITapGestureRecognizer *)sender
{
UIImageView *imgView = (UIImageView *)sender.view;
CGRect rect = [imgView frame];
UIImageView *images = [[UIImageView alloc]initWithFrame:rect];
//rest of code here...
}
The problem here is that I have two scrollView and each scrollview holds multiple books. When I select a book at the 1st scrollView, the images is displayed correctly. But when I select a book inside the 2nd scrollView, the images is displayed incorrectly. Can anyone explain why this happens? Thanks.
---ADDITIONAL INFO---
The two scrollViews have the same width and height. The difference, of course, is there placement. The first scrollView is placed at (0, 0), while the second is at (0, 350). You can imagine the two as "shelves", the first one being the top shelf and the second one being the bottom shelf.
To specify the problem, say that I selected a book inside the second scrollView. The images will then be displayed as if I selected a book in the 1st scrollView. Meaning, the images is displayed in the 1st scrollView instead of the second scrollView.
Because the gestureRecognizer is bound to the first UIImageView and not the second.
[bookCover addGestureRecognizer:singleTap];
Do this for your other UIImageView and you will get the results you want.
I know now what I did wrong! Instead of adding the images as the subview of the scrollViews, I did this:
[self.view addSubView:images];
That's why It keeps appearing on the top side. It should be like this:
[scrollBook addSubview:images];
[scrollFile addSubView:files];
I can't figure out why that view takes the entire screen.
In AppDelegate file
...
self.viewController = [[[ViewController alloc]init]autorelease];
[self.window setRootViewController:self.viewController];
self.window.backgroundColor = [UIColor whiteColor];
..
In ViewController.m
UIView *view = [[UIView alloc]initWithFrame:CGRectMake(30, 30, 30, 30)];
[view setBackgroundColor:[UIColor greenColor]];
self.view = view;
When I run the app the screen is entirely green instead of having just a square in green.
What is wrong here ?
The erroneous line is here:
self.view = view;
When you set a view of a UIViewController that is the root controller, it is guaranteed to fill the screen. Instead, add it as a subview:
[self.view addSubview:view];
And you should be fine.
The view controller automatically manages the size of its root view (self.view), so even if you initialize it with a smaller size it will later get resized to fill the screen. This resizing conveniently also happens when the interface orientation changes (see the answer this question).
As suggested by Richard's answer, you can add your green view as a subview to the controller's root view. The crash you get is probably because the root view does not exist yet when you try to access it. Try the following:
- (void) loadView
{
[super loadView]; // creates the root view
UIView* subView = [[UIView alloc] initWithFrame:CGRectMake(30, 30, 30, 30)];
[subView setBackgroundColor:[UIColor greenColor]];
// because you don't set any autoresizingMask, subView will stay the same size
[self.view addSubview:subView];
}
I have the following code that creates a UIView that I assign to my UITableViewCell's selectedBackgroundView property. Everything works as expected, with the exception of the subview's background, which is transparent.
I use the same code to create a custom view that I assign to backgroundView, and that works fine.
What is causing that subview to be transparent for selectedBackgroundView, and how can I avoid that?
- (UIView*) makeSelectedBackgroundView
{
// dimensions only for relative layout
CGRect containerFrame = CGRectMake(0, 0, 320, 40);
UIView* containerView = [[UIView alloc] initWithFrame:containerFrame];
containerView.autoresizesSubviews = YES;
// dimensions only for relative layout
CGRect subframe = CGRectMake(5, 5, 310, 30);
UIView* subview = [[UIView alloc] initWithFrame:subframe];
subview.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
subview.backgroundColor = [UIColor redColor];
subview.layer.cornerRadius = 5;
subview.layer.borderWidth = 2;
subview.layer.borderColor = [UIColor greenColor].CGColor;
[containerView addSubview:subview];
return containerView;
}
As we can see from name of ivar selectedBackgroundView, this background shown by cell when it was selected.
I've to reload few methods (– setSelected:animated: and – setHighlighted:animated:) of UITableViewCell subclass to reset background color of subviews back to their values. Look's like UIKit do some magic in this template methods (iterating over all UIView subclasses and set their background to clearColor)
This code might be helpful for you:
UIImageView *cellImageView = [[UIImageView alloc]
initWithFrame:CGRectMake(0,
0,
cell.frame.size.width,
cell.frame.size.height
)];
cellImageView.contentMode = UIViewContentModeScaleAspectFit;
// normal background view
[cellImageView setImage:[UIImage imageNamed:#"*<ImageName>*"]];
[cell addSubview:cellImageView];
[cell sendSubviewToBack:cellImageView];
[cellImageView release], cellImageView = nil;
Here cell is an object of custom UITableViewCell.
Also you can set backgroundColor property.
I would try to set the alpha for both containerView and subView to 1.0
[containerView setAlpha:1.0];
...
[subview setAlpha:1.0];
this should make your controls totally opaque.
You could also create some images for the background and use that images in state of creating 2 views. Let's say you create 2 image (normalBackground.png and selectedBackground.png) and then set this images as cell background. Here is a nice tutorial.
Try setOpaque:YES on your views.
In the end, I ended up subclassing UITableViewCell which contained a custom view object, and that worked.
I am using an applicationMusicPlayer and when i try to change the volume appear the visual notification, as shown in the picture.
Here the code I am using:
[MPMusicPlayerController applicationMusicPlayer] setVolume:newVolune];
Anyone knows how to hide this notification?
I don't know where the docs says so, but if you add a MPVolumeView view to your app the system volume overlay goes away. Even if it is not visible:
- (void) viewDidLoad
{
[super viewDidLoad];
MPVolumeView *volumeView = [[MPVolumeView alloc] initWithFrame: CGRectZero];
[self.view addSubview: volumeView];
[volumeView release];
...
}
You can use the hardware volume buttons, the setVolume method or directly interact with the control (if visible) that the overlay doesn't show up.
For iOS6 I had to set an image with alpha 0 and non-zero size to the MPVolumeView's image fields in order to get the default volume change notification to disappear.
// hide the hardware volume slider
UIImage *thumb = [[UIImage alloc] initWithCIImage:[UIImage imageNamed:#"volumeHider"].CIImage scale:0.0 orientation:UIImageOrientationUp];
MPVolumeView *hwVolume = [[MPVolumeView alloc] initWithFrame:self.frame];
[hwVolume setUserInteractionEnabled:NO];
hwVolume.showsRouteButton = NO;
[hwVolume setVolumeThumbImage:thumb forState:UIControlStateNormal];
[hwVolume setMinimumVolumeSliderImage:thumb forState:UIControlStateNormal];
[hwVolume setMaximumVolumeSliderImage:thumb forState:UIControlStateNormal];
[self addSubview:hwVolume];
This made the MPVolumeView be "visible" on the screen, but invisible to the user.
I encountered the same issue recently. Instead of adding the MPVolumeView to current view controller's view, I add it to the application's window once at the start of the app:
CGRect rect = CGRectMake(-500, -500, 0, 0);
MPVolumeView *volumeView = [[MPVolumeView alloc] initWithFrame:rect];
[self.window addSubview:volumeView];
This works in both iOS 7 and 8.
Swift 3
You can hide the System MPVolumeView using
override func viewDidLoad() {
super.viewDidLoad()
let volumeView = MPVolumeView(frame: CGRect.zero)
self.view.addSubview(volumeView)
}
I had success with this in iOS 6. Although it wouldn't perform well. It caused quite a bit of lag when sliding the thumbImage. I did have to take out the last 2 lines of code in order for this to work.
[volumeView release];
...
For me, on iOS 7, none of above solutions worked. Here is how I did it:
_volume = [[MPVolumeView alloc] initWithFrame: CGRectMake(-100,-100,16,16)];
_volume.showsRouteButton = NO;
_volume.userInteractionEnabled = NO;
[self.view addSubview:_volume];
[_volume release];
That is, simply set MPVolumeView's frame to an off-screen location such as (-100,-100).
I currently show a modal UIViewController in the formSheet style that was presented with the coverVertical animation. I am trying to present another modal UIViewController from it, using currentContext for the presentation style and flipHorizontal for the animation style. It does work, but there is a solid white white background behind the flip as it occurs. Any advice on how to successfully present another formsheet modal UIViewController using the flipHorizontal style from a pre-existing modal UIViewController in the formSheet style would be appreciated please! Thanks
Code:
// Loading of first modalVC
- (void)showModalVC {
Modal1VC *modal1VC = [[Modal1VC alloc] init];
modal1VC.modalPresentationStyle = UIModalPresentationFormSheet;
modal1VC.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentModalViewController:modal1VC animated:YES];
[modal1VC release];
modal1VC.view.superview.bounds = CGRectMake(0, 0, 400, 400);
}
// Loading of second modalVC in Modal1VC
- (void)buttonTapped:(id)sender {
UIViewController *modal2VC = [[UIViewController alloc] init];
modal2VC.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
modal2VC.modalPresentationStyle = UIModalPresentationCurrentContext;
modal2VC.view.backgroundColor = [UIColor greenColor];
[self presentModalViewController:modal2VC animated:YES];
[modal2VC release];
modal2VC.view.superview.bounds = CGRectMake(0, 0, 400, 400);
}
UIViewController *presentingViewController = //allocate your VC
[modalViewController setModalTransitionStyle:UIModalTransitionStyleFlipHorizontal];
UIViewController *modalViewController = //your modal VC
[presentingViewController presentModalViewController:modalViewController animated:YES];
This is all the code you need ;)
It sounds like your transition is working, but the white background shown on the flip transition is the problem?
During the flip transition, the white background that is shown is actually the window. You can change the color that is shown by setting the backgroundColor property of window in the AppDelegate.
That would seem to be a limitation of presentModalViewController:animated:.
Instead of [self presentModalViewController:modal2VC animated:YES], you may be able to get the effect you want using UIView animations. Perhaps something like this:
[UIView transitionWithView:self.view.window
duration:0.3
options:UIViewAnimationOptionTransitionFlipFromRight
animations:^{
[self presentModalViewController:modal2VC animated:NO];
} completion:NULL];