I want an image to automatically align to the top, I figure the only want to do this is through making a frame that positions it that way. After doing some research, I can't seem to figure out why this code doesn't move the image at all... I have substituted many values in the topPadding and leftPadding variables..
- (void)constructImageView:(UIImage *)image {
CGFloat topPadding = 20.f;
CGFloat leftPadding = 30.f;
CGRect frame = CGRectMake(leftPadding, topPadding, image.size.width, image.size.height);
self.imageView = [[UIImageView alloc] initWithFrame:frame];
self.imageView.image = image;
[self addSubview:self.imageView];
}
Are you using Autolayout? If yes, setFrame: does not work properly with autolayout. If thats the case, then your options are:
Use this: self.view.translatesAutoresizingMaskIntoConstraints = YES
Write your own constraints instead of setting the view's frame
Related
I am trying to create a subclass of UIView that will show a list of fixed sized UIImages similar to how a UILabel displays letters.If all the images won't fit on one line, the images are arranged on multiple lines.
How can I achieve this using autolayouts so that if I put this view in a UIStackView the images will be listed correctly?
Here is a sample if I did it using fixed position :
- (void) layoutSubviews{
[super layoutSubviews];
CGRect bounds = self.bounds;
CGRect imageRect = CGRectMake(0, 0, 30, 30);
for (UIImageView* imageView in self.imageViews){
imageView.frame = imageRect;
imageRect.origin.x = CGRectGetMaxX(imageRect);
if (CGRectGetMaxX(imageRect) > CGRectGetMaxX(bounds)){
imageRect.origin.x = 0.0;
imageRect.origin.y = CGRectGetMaxY(imageRect);
}
}
}
Update:
Here is a sample project to show the issue.
https://github.com/datinc/DATDemoImageListView
Here the link for ImageListView
https://github.com/datinc/DATDemoImageListView/blob/master/DATDemoImageListView/DATDemoImageListView.m
You should overwrite intrinsicContentSize returning the preferred content size of your view.
The problem is that in intrinsicContentSize the view has not it's final bounds. You can use an internal height constraint, and overwrite updateConstraints:
- (void)updateConstraints {
CGFloat theWidth = CGRectGetWidth(self.bounds);
NSUInteger theCount = [self.subviews count];
CGFloat theRows = ceilf(theCount / floorf(theWidth / 30.0));
self.heightConstraint.constant = 30.0 * theRows;
[super updateConstraints];
}
In viewDidAppear: and on layout changes (e. g. rotation) you have to call setNeedsUpdateConstraints to get a proper initial layout of the image views.
how can i set the height of UIImageView and leaving other attributes as it is from the .xib? i have UIImageView in .xib file but i only want to set height of it programmatically. can it be done?
Yes It can be done. For eg: If you have UIImageView as imageView then do the below to change the specific frame value.
Way - 1
CGRect rect = imageView.frame;
rect.size.height = /* YOUR_HEIGHT */;
imageView.frame = rect;
Way - 2
imageView.frame = CGRectMake(imageView.frame.origin.x, imageView.frame.origin.y, imageView.frame.size.width, /* YOUR_HEIGHT */);
I highly recommend you to add https://github.com/AlexDenisov/FrameAccessor to your project. It allows to work with frame directly, for example:
view.x = 15.;
view.width = 167.;
I'm trying to create a custom view which containes several images. I do that by adding them programmatically. The problem is that those subviews overlap each other and I can't find the way to change that. The only solution I can see is doing something like setting frames for each new image programmatically. I would be grateful if someone could tell me what is the best way to solve this issue.
for (id image in self.images) {
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
[self.imageViews addObject:imageView];
[self addSubview:imageView];
}
If you wanna make your customView like UICollectionView you need a UIScrollView and add your subviews in it. Everytime when you add a subview change frame location so it could be something like this:
int xPosition = 0;
int yPosition =0;
for (id image in self.images) {
if (xPosition>self.view.frame.size.width) {
//give size to every imageView and every time in loop change the location
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(xPosition, yPosition, 50, 50)];
imageView.image = image;
yPosition = yPosition + 50;
[self.view addSubView:imageView];
}
else {
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(xPosition, yPosition, 50, 50)];
imageView.image = image;
xPosition = xPosition + 50;
[self.view addSubView:imageView];
}
}
Without using Interface Builder your only real options are to change the frame or the center.
imageView.frame = CGRectMake(x coord, y coord, width, height);
This method lets you resize and move whereas changing the center lets you do just that, move the center of the view.
or
imageView.center = CGPointMake(x coord, y coord);
Or as recommended add constraints.
I have a view that is set up nicely using autolayout. The view contains a series of labels stacked from top to bottom. I am allowing the intrinsic size of these labels to determine the size of the view.
The final step is to add a background from an image. I started by trying the colorWithPatternImage method on UIColor but this isn't quite what I am looking for. I do not want to tile the image, and I can not guarantee it will always be larger than the intrinsic size of the view.
Similarly, adding a uiImageView to the view itself doesn't quite work. The view will expand to accommodate the image when I want to keep the intrinsic size based on the labels.
I guess what I am looking for is the following.
1) The background should have no effect on the size of the view.
2) The image should be scaled to fill the view but in it's original aspect ration (so cropping edges if necessary).
Any ideas appreciated.
In my case, I needed it for a UIImageView inside a dynamically-sized view in a UITableViewCell, but the image refused to shrink below its instristic size and instead worked as a minimum-size constraint for the superview. The only way I could get it ignore the intristic size is by lowering the priority at which it is enforced, right after creating the cell:
[imageView setContentCompressionResistancePriority:UILayoutPriorityDefaultLow
forAxis:UILayoutConstraintAxisHorizontal];
[imageView setContentCompressionResistancePriority:UILayoutPriorityDefaultLow
forAxis:UILayoutConstraintAxisVertical];
After this, all my constraints magically started working. In the OP's case, setting UIViewContentModeScaleAspectFill is also required, as per Mundi's answer.
In Interface Builder, add a UIImageView as the first subview to the view. Make sure its size always matches the view.
Then, in Interface Builder or code, set the contentMode:
backgroundImageView.contentMode = UIViewContentModeScaleAspectFill;
Here's how I would approach this. Hopefully it helps. :)
CGRect contentFrame = CGRectMake(0, 0, self.view.frame.size.width, 0); // This will be the frame used to create the background image view.
UIEdgeInsets contentInsets = UIEdgeInsetsMake(20, 20, 20, 20); // The margins by which the labels will be inset from the edge of their parent view.
CGFloat labelHeight = 21;
CGFloat verticalGap = 8; // The vertical space between labels
CGFloat y = contentInsets.top;
int numberOfLabels = 10;
for (int i = 0; i < numberOfLabels; i++) {
CGRect frame = CGRectMake(contentInsets.left, y, self.view.frame.size.width - (contentInsets.left + contentInsets.right), labelHeight);
UILabel *label = [[[UILabel alloc] initWithFrame: frame] autorelease];
// customize the label here
[self.view addSubview: label];
contentFrame = CGRectUnion(contentFrame, label.frame);
y += labelHeight + verticalGap;
}
contentFrame.size.height += contentInsets.bottom;
UIImageView *backgroundImageView = [[[UIImageView alloc] initWithFrame: contentFrame] autorelease];
[backgroundImageView setClipsToBounds: YES];
[backgroundImageView setContentMode: UIViewContentModeScaleAspectFill];
[backgroundImageView setImage: [UIImage imageNamed: #"background_image.png"]];
[self.view insertSubview: backgroundImageView atIndex: 0];
I have a UIScrollView that contains a view derived from UIView that uses CATiledLayer. Essentially, in my ViewController viewDidLoad:
_tiledView = [[TiledView alloc] initWithFrame:rect tileSize:_tileSize];
_scrollView = [[ScrollingView alloc] initWithFrame:rect];
_scrollView.contentSize = _tiledView.frame.size;
_scrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
_scrollView.decelerationRate = UIScrollViewDecelerationRateFast;
_scrollView.scrollEnabled = YES;
_scrollView.delegate = self;
[_scrollView addSubview:_tiledView];
Initially, _tiledView is a 4x4 grid of 256x256 tiles. I'm trying increase the dimensions of _tiledView at runtime. When constructing _tiledView, I simply compute the size of the view by multiplying the number of tiles by its size. Then I set the size of _tiledView.frame and _tiledView.bounds, e.g.:
CGRect frame = self.frame;
frame.origin = CGPointZero;
frame.size = CGSizeMake(tileSize.width*4, tileSize.height*4);
self.frame = frame;
self.bounds = frame;
Now, when I hit a button in the interface, all I want to accomplish as a first step is increasing the dimensions of _tiledView by one 256x256 tile to both right and bottom. This is what I attempted:
- (void)addTiles:(id)sender
{
CGRect rect = _tiledView.frame;
rect.size.width += _tileSize.width;
rect.size.height += _tileSize.height;
_tiledView.frame = rect;
_tiledView.bounds = rect;
CGSize size = _scrollView.contentSize;
size.width += _tileSize.width;
size.height += _tileSize.height;
_scrollView.contentSize = size;
[_scrollView setNeedsLayout];
}
However, this doesn't work as expected. What happens is that _tiledView gets bigger as if it had been zoomed in - same number of tiles as the beginning though, i.e. 4x4. I checked the _scrollView.contentsScaleFactor property and it says 1.0. I assume _scrollView did not technically zoom the contents in.
I was expecting _tileView to stay put in its current place in the interface but add 9 new tiles, i.e. 4 to the right, 4 at the bottom and 1 at the bottom-right corner. Instead, the initial 16 tiles got bigger to fill in the space that could have been filled by 25 tiles.
What am I missing? What am I doing wrong? Any help would be appreciated.
In case anyone finds it useful. After digging further, I realized that I the contentMode defaults to ScaleToFill. So I set it to:
_tiledView.contentMode = UIViewContentModeRedraw;
upon initialization. And adjusted addTiles like this:
CGRect rect = _tiledView.frame;
rect.size.width += _tileSize.width;
rect.size.height += _tileSize.height;
_tiledView.frame = rect;
_tiledView.bounds = rect;
_scrollView.contentSize = rect.size;
[_tiledView setNeedsDisplay];
And, that had the effect I was looking for.