I want an imageview to appear centre at the bottom,i added the imageview to another imageview in the view controller.the result is imageview is appearing at the bottom but not exactly at centre, can any one suggest what is wrong in my code?
-(void)viewWillAppear:(BOOL)animated
{
UIImageView *imgView=[[UIImageView alloc]init];
[imgView setTranslatesAutoresizingMaskIntoConstraints:NO];
UIImageView *mspimgvw=[[UIImageView alloc]init];
[mspimgvw setTranslatesAutoresizingMaskIntoConstraints:NO];
mspimgvw.image=[UIImage imageNamed:#"msplogo.jpg"];
[self.imgView addSubview:mspimgvw];
[self.view addSubview:imgView];
CGFloat bottom=0;
[imgView addConstraint:[NSLayoutConstraint constraintWithItem:mspimgvw attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:imgView attribute:NSLayoutAttributeBottom multiplier:1 constant:bottom-40]];
[imgView addConstraint:[NSLayoutConstraint constraintWithItem:mspimgvw attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:imgView attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:bottom-40]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|[imgView]|" options:0 metrics: 0 views:dicViews]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|[imgView]|" options:0 metrics: 0 views:dicViews]];
}
I want image to appear to the centre of the view controller.What to change in my code?
Here you go:
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView
attribute:NSLayoutAttributeCenterX
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeCenterX
multiplier:1.f
constant:0.f]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView
attribute:NSLayoutAttributeBottom
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeBottom
multiplier:1.f
constant:0.f]];
Related
I am trying to add two UIView on ViewController. One of them is plain UIView and other is UITableView. I am not quite sure how to set height constraint on them in such away that UITableView will be of height required for its content and other view can resize itself based on UITableView height.
Below is the simple sketch and code I am using for setting up those constraints.
NSDictionary *views = NSDictionaryOfVariableBindings(_infoView,_infoTableView);
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"[_infoView]"
options:0
metrics:nil
views:views]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:[_infoView]-[_infoTableView]"
options:0
metrics:nil
views:views]];
// Width constraint
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.infoView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeWidth
multiplier:1.0
constant:0]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.infoTableView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeWidth
multiplier:1.0
constant:0]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.infoView
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeTop
multiplier:1.0
constant:0]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.infoTableView
attribute:NSLayoutAttributeBottom
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeBottom
multiplier:1.0
constant:0]];
Any comments / feedback would be highly appreciated.
Thanks.
You are on the right track. The trick here is that you need to dynamically update the height of tableView to its contentSize.height so infoView will know it should either be vertically expanded or shrunk:
First you define a property that will hold the height constraint:
#property (nonatomic, strong) NSLayoutConstraint *tableViewHeightConstraint;
- (void)viewDidLoad {
...
self.tableViewHeightConstraint = [NSLayoutConstraint constraintWithItem:self.tableView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNotAnAttribute
multiplier:0.0
constant:350.0];
}
Then you can update the height constraint right after tableView knows its contentSize (ex: viewDidAppear:animated):
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
self.tableViewHeightConstraint.constant = self.tableView.contentSize.height;
[self.view layoutIfNeeded];
}
I created a sample project for you so you can play around with it to have a better understanding about what I intend to do.
Its been 2 days working on this problem and i just can't figure it out.
I have a UIScrollView stretched in all my view and i am adding to it as subViews a random number of UIImageViews, and i am enabling paging so it will look like a gallery app.
My problem is when i rotate the screen, the images frames stays the same (this is probably because of the constraints) so i tried to give the images constraints and it worked they would rotate perfectly but then a problem appeared where the scroll view wont scroll anymore and the images are on top of each other ..
This is my code :
-(void)setupScrollView
{
for(int i = 0 ; i < [_arrayOfImages count] ; i++)
{
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(self.view.frame.size.width*i, 0, self.view.frame.size.width, self.view.frame.size.height)];
[imageView setImage:[[_arrayOfImages objectAtIndex:i] getImageForImageView:imageView]];
[imageView setUserInteractionEnabled:YES];
[imageView setContentMode:UIViewContentModeScaleAspectFit];
[imageView setTranslatesAutoresizingMaskIntoConstraints:NO];
[_scrollView addSubview:imageView];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeading multiplier:1.f constant:0.f]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTrailing multiplier:1.f constant:0.f]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1.f constant:0.f]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeBottom multiplier:1.f constant:0.f]];
}
[_scrollView setContentSize:CGSizeMake(self.view.frame.size.width*[_arrayOfImages count], self.view.frame.size.height)];
}
Can anyone help me please ? thanks
You need to change the frame of UIScrollView and the UIImageViews in Autorotate delegate methods. After that you have to change the ContentSize of UIScrollView.
- (BOOL) shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation{}
//ios 7
-(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation{}
duration:(NSTimeInterval)duration -
-(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation{}
//ios 8
-(void)viewWillTransitionToSize:(CGSize)size
withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator{
if (size.width > size.height) {
// Positions for Landscape
} else {
// Positions for Portrait
}
}
I'am not really sure, because I need to see all application, but you can try following code
-(void)setupScrollView
{
for(int i = 0 ; i < [_arrayOfImages count] ; i++)
{
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(self.view.frame.size.width*i, 0, self.view.frame.size.width, self.view.frame.size.height)];
[imageView setImage:[[_arrayOfImages objectAtIndex:i] getImageForImageView:imageView]];
[imageView setUserInteractionEnabled:YES];
[imageView setContentMode:UIViewContentModeScaleAspectFit];
[imageView setTranslatesAutoresizingMaskIntoConstraints:NO];
[_scrollView addSubview:imageView];
[imageViewArray addObject:imageView]
if (i == 0) {
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeading multiplier:1.f constant:0.f]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTrailing multiplier:1.f constant:0.f]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1.f constant:0.f]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeBottom multiplier:1.f constant:0.f]];
} else {
UIImageView * previousView = [imageViewArray objectAtIndex:i-1];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:previousView attribute:NSLayoutAttributeLeading multiplier:1.f constant:0.f]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:previousView attribute:NSLayoutAttributeTrailing multiplier:1.f constant:0.f]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:previousView attribute:NSLayoutAttributeTop multiplier:1.f constant:0.f]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:previousView attribute:NSLayoutAttributeBottom multiplier:1.f constant:0.f]];
}
}
[_scrollView setContentSize:CGSizeMake(self.view.frame.size.width*[_arrayOfImages count], self.view.frame.size.height)];
}
Also, you need to declare imageViewArray as NSMutableArray:
add to #interface:
NSMutableArray * imageViewArray;
and in viewDidLoad:
imageViewArray = [[NSMutableArray alloc] init];
I am trying to add a gray uiview overlay using autolayouts so that when you rotate the device it automatically still covers the entire screen. How would this be done programatically?
It is easy, you need 4 constraints to do that - top, bottom, left and right:
NSLayoutConstraint *topConstraint = [NSLayoutConstraint constraintWithItem:view attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:superview attribute:NSLayoutAttributeTop multiplier:1.0f constant:0.0f];
NSLayoutConstraint *bottomConstraint = [NSLayoutConstraint constraintWithItem:view attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:superview attribute:NSLayoutAttributeBottom multiplier:1.0f constant:0.0f];
NSLayoutConstraint *leftConstraint = [NSLayoutConstraint constraintWithItem:view attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:superview attribute:NSLayoutAttributeLeft multiplier:1.0f constant:0.0f];
NSLayoutConstraint *rightConstraint = [NSLayoutConstraint constraintWithItem:view attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:superview attribute:NSLayoutAttributeRight multiplier:1.0f constant:0.0f];
Try this:
UIView *greyView = [UIView new];
[self.view addSubview:greyView];
greyView.translatesAutoresizingMaskIntoConstraints = NO;
NSDictionary *viewDictionary = #{#“greyView”:greyView};
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|-0-[myView]-0-|“ options:0 metrics:nil views:viewDictionary]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#“H:|-0-[myView0]-0-|” options:0 metrics:nil views:viewDictionary]];
I am creating a customalertview that needs to be added as a subview to UIWindow. I've setup the constraints for it's subviews correctly but I'm confused as to when/how to set the constraints on the view itself in relation to the window.
I would like the width of the alertview to be 70% of the width of the screen. The height is already in relation to it's subviews.
- (void)show {
UIWindow *window = [[UIApplication sharedApplication] keyWindow];
[window addSubview:self];
[self addConstraint:[NSLayoutConstraint constraintWithItem:self attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:[UIApplication sharedApplication].keyWindow attribute:NSLayoutAttributeWidth multiplier:0.7 constant:0]];
[self addConstraint:[NSLayoutConstraint constraintWithItem:self attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:_messageLabel attribute:NSLayoutAttributeBottom multiplier:1.0 constant:10]];
[self addConstraint:[NSLayoutConstraint constraintWithItem:self attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:(_imageView.image ? _imageView : _titleLabel) attribute:NSLayoutAttributeTop multiplier:1.0 constant:-10]];
}
What am I doing wrong? I am getting the following error message:
NSLayoutConstraint:0x181cd7c0 WFSoftAlertView:0x16e384c0.width == 0.7*UIWindow:0x16e7c8c0.width>
When added to a view, the constraint's items must be descendants of that view (or the view itself). This will crash if the constraint needs to be resolved before the view hierarchy is assembled.
WFSoftAlertView.translatesAutoresizingMaskIntoConstraints=NO;
NSDictionary *views = NSDictionaryOfVariableBindings(WFSoftAlertView);
float width30 = self.view.frame.size.width*.3;
width30 = width30/2; // divided by 2 for padding of its left/rigth
NSString *str =[NSString stringWithFormat:#"%f",width30];
NSDictionary *metrics = #{#"width":str};
[self.view addSubview:WFSoftAlertView];
//add the WFSoftAlertView in center(x) of superview with a padding of "width"
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"|-width-[WFSoftAlertView]-width-|" options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom metrics:metrics views:views]];
// if you want center(y)
NSLayoutConstraint *centerY = [NSLayoutConstraint
constraintWithItem:WFSoftAlertView
attribute:NSLayoutAttributeCenterY
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeCenterY
multiplier:1.0f
constant:0.f];
Try changing your constraintWithItem from
self
to
self.view
I'm trying to manually animate in a UIView, contained in a UIViewController, from the top of the screen. This view will have a height of 150px.
I setup layout constraints for when it's "collapsed" and when it's "expanded" (shown). I animate between the two constraints when I want to hide/show, respectively.
I setup the view contained in this UIViewController in IB with a simple UILabel in the upper-left of the view.
CGFloat closeUpViewHeight = 150.f;
self.closeUpViewController = [[[CloseUpViewController_Phone alloc] initWithNibName:#"CloseUpViewController_Phone"
bundle:nil]
autorelease];
[self addChildViewController:self.closeUpViewController];
[self.view addSubview:self.closeUpViewController.view];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.closeUpViewController.view
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeHeight
multiplier:0.f
constant:closeUpViewHeight]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.closeUpViewController.view
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeWidth
multiplier:1.f
constant:0.f]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.closeUpViewController.view
attribute:NSLayoutAttributeCenterX
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeCenterX
multiplier:1.f
constant:0.f]];
self.expandedCloseUpViewConstraint = [NSLayoutConstraint constraintWithItem:self.closeUpViewController.view
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeTop
multiplier:0.f
constant:0.f];
self.collapsedCloseUpViewConstraint = [NSLayoutConstraint constraintWithItem:self.closeUpViewController.view
attribute:NSLayoutAttributeBottom
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeTop
multiplier:1.f
constant:-1.f];
Anyone know why the resulting UILabel has aliasing problems?
Fixed my problem, pretty dumb mistake.
Inside the setup for my view controller, I added a drop shadow to the UIView and accidentally had carried over this:
self.view.layer.masksToBounds = NO;
self.view.layer.shadowOffset = CGSizeMake(0, 2);
self.view.layer.shadowRadius = 3;
self.view.layer.shadowOpacity = 0.8;
self.view.layer.shouldRasterize = YES; //<--- Don't rasterize.
Removing the shouldRasterize line fixes the issue here.