This is my first time working with UICollectionView.
I've got everything set up and laid out as it should be (as far as I know). I've had a little bit of difficulty with the way the dequeue function works for the UICollectionView, but I think I've gotten past that. It was tricky setting up my custom cell classes when I didn't know if initWithFrame would be called or prepareForReuse.
I'm pretty sure the problem lies within the prepareForReuse function, but where is the question.
What happens is, the cells will apparently randomly draw at the top-left of the collection view and some cells will not be where they belong in the grid. (see image attached)
When bouncing, scrolling, and zooming (so as to cause reuse to occur), the problem happens. Randomly a slide will appear in the top left, and other slides will randomly disappear from the grid.
( I need more rep to post an image. Ugh. :| If you can help me, I'll email you the image. bmantzey#mac.com )
-(UICollectionViewCell*)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
Slide* thisSlide = [_presentation.slidesInEffect objectAtIndex:indexPath.row];
[BuilderSlide prepareWithSlide:thisSlide];
BuilderSlide* cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"PlainSlide" forIndexPath:indexPath];
return cell;}
I'm using a static method to set the Slide object, which contains the data necessary to either prepare the asynchronous download or retrieve the image from disk cache.
It's simply:
+(void)prepareWithSlide:(Slide*)slide{
if(s_slide)
[s_slide release];
s_slide = [slide retain];}
I'm not sure if it's a big no-no to do this but in my custom Cell class, I'm calling prepareForReuse in the initWithFrame block because I need that setup code to be the same:
-(id)initWithFrame:(CGRect)frame{
self = [super initWithFrame:frame];
if(self)
{
[self prepareForReuse];
}
return self;}
Here's the prepareForReuse function:
-(void)prepareForReuse{
CGSize size = [SpringboardLayout currentSlideSize];
[self setFrame:CGRectMake(0, 0, size.width, size.height)];
self.size = size;
// First remove any previous view, so as not to stack them.
if(_builderSlideView)
{
if(_builderSlideView.slide.slideID == s_slide.slideID)
return;
[_builderSlideView release];
}
for(UIView* aView in self.contentView.subviews)
{
if([aView isKindOfClass:[BuilderSlideView class]])
{
[aView removeFromSuperview];
break;
}
}
// Then setup the new view.
_builderSlideView = [[BuilderSlideView alloc] initWithSlide:s_slide];
self.builderCellView = _builderSlideView;
[s_slide release];
s_slide = nil;
[self.contentView addSubview:_builderSlideView];
if([SlideCache isImageCached:_builderSlideView.slide.slideID forPresentation:_builderSlideView.slide.presentationID asThumbnail:YES])
{
[_builderSlideView loadImageFromCache];
}
else
{
[_builderSlideView loadView];
}}
Finally, when the slide image has been downloaded, a Notification is posted (I plan on changing this to a delegate call). The notification simply reloads the cell that has received an update. Here's the notification code:
-(void)didLoadBuilderCellView:(NSNotification*)note{
BuilderCellView* cellView = [[note userInfo] objectForKey:#"cell"];
BuilderSlideView* slideView = (BuilderSlideView*)cellView;
NSIndexPath* indexPath = [self indexPathForSlide:slideView.slide];
if(indexPath)
[self.collectionView reloadItemsAtIndexPaths:[NSArray arrayWithObject:indexPath]];}
Note that the slide objects exist in the model.
Any ideas as to what may be causing this problem? Thanks in advance!
The problem that was causing the cells to draw top left and/or disappear was caused by infinite recursion on a background thread. Plain and simply, I wasn't implementing the lazy loading correctly and safely. To solve this problem, I went back to the drawing board and tried again. Proper implementation of a lazy loading algorithm did the trick.
I am using iCarousel to display instances of a custom view I have created in IB. When the carousel loads, the first view in the carousel displays correctly, like this:
However, the other indexes seem to be ignoring my constraints, like this:
Once I click on this view, the layout corrects itself. Also notice that the first index now has a screwed up layout:
Any idea how to correct this? My code relating to the carousel:
- (NSUInteger)numberOfItemsInCarousel:(iCarousel *)carousel
{
//return the total number of items in the carousel
NSLog(#"size=%d",audio.count);
return audio.count;
}
- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view
{
NSLog(#"get view for index %d",index);
Audio *aud = [audio objectAtIndex:index];
CGRect screenRect = [[UIScreen mainScreen] bounds];
CGFloat screenWidth = screenRect.size.width;
CGFloat screenHeight = screenRect.size.height;
AudioView *aView;
float height = screenWidth*.5;
float width = height * (16.0/9.0);
//create new view if no view is available for recycling
if (view == nil)
{
aView = [[[NSBundle mainBundle] loadNibNamed:#"AudioView" owner:self options:nil] objectAtIndex:0];
[aView setFrame:CGRectMake(0, 0, width, height)];
}else{
aView=(AudioView *)view;
}
aView.layer.cornerRadius=8;
NSLog(#"%f",aView.frame.size.height);
NSLog(#"%f",aView.frame.size.width);
aView.backgroundColor=[UIColor alizarinColor];
aView.textLabel.text=aud.text;
aView.titleLabel.text=aud.name;
if (rowCurrentlyPlaying==index&&isPlaying) {
aView.imageView.image = [UIImage imageNamed:#"pause.png"];
}else{
aView.imageView.image = [UIImage imageNamed:#"play.png"];
}
return aView;
}
- (CGFloat)carousel:(iCarousel *)carousel valueForOption:(iCarouselOption)option withDefault:(CGFloat)value
{
if (option == iCarouselOptionSpacing)
{
return value * 1.1f;
}
return value;
}
- (void)carousel:(iCarousel *)carousel didSelectItemAtIndex:(NSInteger)index{
NSLog(#"Clicked");
if(index==self.carousel.currentItemIndex){
Audio *aud = [audio objectAtIndex:index];
NSURL *audUrl = [NSURL URLWithString:aud.audioUrl];
if (rowCurrentlyPlaying==index) {
if (isPlaying) {
[anAudioStreamer pause];
isPlaying=NO;
}else{
[anAudioStreamer play];
isPlaying=YES;
}
}else{
rowCurrentlyPlaying=index;
isPlaying=YES;
aPlayerItem = [[AVPlayerItem alloc] initWithURL:audUrl];
anAudioStreamer = [[AVPlayer alloc] initWithPlayerItem:aPlayerItem];
[anAudioStreamer play];
}
[carousel reloadData];
}
}
EDIT:I tried this on iPad as well, and I thought these screenshots might help shed some light (please ignore the hilarious font sizes). It looks like it's just not stretching to the full width when not selected.
Correct layout:
Incorrect layout:
I have been scouring all day long for an answer to this question - the same thing was happening to me. Setting the frame of the Custom UIView does not work.
The solution is a bit strange:
Go to the xib file for the Custom UIView. I'll also assume that you
have corresponding subclass (.h and .m files) for the Custom UIVIew
Add a subview that covers the whole view. I'll call this the background view.
Add the text views, etc as subviews of the background view and set the constraints relative to the background view.
For the background view, add the following constraints: Top Space to Superview, Leading Space to Superview, Width Equals:
, Height Equals:
Create two outlets, one from the width constraint and one for the height constraint from step 4. These outlets should be in the
.h file of the Custom UIView.
In the viewForItemAtIndex method you have above, continue to allocate and initialize the Custom View using the loadNibNamed
method. However, after that, set the width and height constraint
constants based on the bounds of the carousel (or whatever width and
height you desire). For example,
CustomView *customView = (CustomView *) view;
customView.widthConstraint.constant = carousel.bounds.size.width;
customView.heightConstraint.constant = carousel.bounds.size.height;
i haven't looked at iCarousel in a while, but this is from the readMe file in whatever version I have here
iCarousel supports the following built-in display types:
- iCarouselTypeLinear
- iCarouselTypeRotary
- iCarouselTypeInvertedRotary
- iCarouselTypeCylinder
- iCarouselTypeInvertedCylinder
- iCarouselTypeWheel
- iCarouselTypeInvertedWheel
- iCarouselTypeCoverFlow
- iCarouselTypeCoverFlow2
- iCarouselTypeTimeMachine
- iCarouselTypeInvertedTimeMachine
You can also implement your own bespoke carousel styles using `iCarouselTypeCustom` and the `carousel:itemTransformForOffset:baseTransform:` delegate method.
NOTE: The difference between `iCarouselTypeCoverFlow` and `iCarouselTypeCoverFlow2` types is quite subtle, however the logic for `iCarouselTypeCoverFlow2` is substantially more complex. If you flick the carousel they are basically identical, but if you drag the carousel slowly with your finger the difference should be apparent. `iCarouselTypeCoverFlow2` is designed to simulate the standard Apple CoverFlow effect as closely as possible and may change subtly in future in the interests of that goal.
Im not sure if you understand that the iCourousel is applying transforms to those views that are not the current selection, this is deliberate. Its having a stab at emulating Apple's cover flow api, (which is unavailable to us)..
ok so your carousel object has a property of type iCarouselType called type, from the enum above, best bet is trying each of these to find the one which suits you.
I have figure out a thing that looks different than the usual implementation of iCarousel.
In method - (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view
I guess you need to use : objectAtIndex:index]; instead of objectAtIndex:0];
if (view == nil)
{
aView = [[[NSBundle mainBundle] loadNibNamed:#"AudioView" owner:self options:nil] objectAtIndex:0];
[aView setFrame:CGRectMake(0, 0, width, height)];
}
I have a simple piece of code that I have used in my live app as :
- (UIView *)carousel:(iCarousel *)_carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view
{
if (view == nil)
{
view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 200, 200)];
view.contentMode = UIViewContentModeCenter;
[view addSubview:[items objectAtIndex:index]];
}
else
{
view = [items objectAtIndex:index];
}
view = [items objectAtIndex:index];
return view;
}
Hope that helps.
when you crate Audio view in "viewForItemAtIndex", you just set frame of view
[aView setFrame:CGRectMake(0, 0, width, height)];
I think you have to set frame of titlelabel and textlabel of aView, to get full width text.
For Second issue , when you click on view, that view display properly but previous view's text get cut.
I think you have are reloading all carousel view on click ,
[carousel reloadData];
instead of that you have to reload only that view on which you are clicked. for that you can use
(void)reloadItemAtIndex:(NSInteger)index animated:(BOOL)animated;
May this line solve your issue.
Enjoy....
For me helped next:
Move function with iCarousel configuring (dataSource and etc.) to viewDidAppearfunction. Otherwise, my frames were not correct.
Then just write something like this:
currentView?.frame.size.width = carouselView.bounds.size.width
currentView?.frame.size.height = carouselView.bounds.size.height
Hope it helps to someone
I would like to implement an app using a UIScrollView with paging, similar to the apple weather app.
But I am a little concerned about performance. The example implementation I have been using loads all of the views then the application launches. After a certain point, once this prove slow?
I wonder how Apple's camera roll is dealing with this, where a user may have 100+ photos that can be scrolled through. Should I try to figure out a way to build the view only when it is needed? Or maybe there is a way to replicate the dequeue reusable cell technique from a UITableView, only for horizontal view loading, since each view will have the same layout.
By far the most efficient solution (and this is used in many photo-browsing apps such as Facebook, and probably the native Photos app too) is going to be to load the content on-demand, just as UITableView does. Apple's StreetScroller sample project should get you on the right track.
A very efficient solution, is to make sure to reuse any views whenever possible. If you are going to be simply displaying images, you could use a subclass of UIScrollView, and layout these reusable views within layoutSubviews. Here you could detect what views are visible and not visible and create the subviews as needed.
An example dequeuing function may look like:
- (UIImageView *)dequeueReusableTileWithFrame:(CGRect) frame andImage:(UIImage *) image
{
UIImageView *tile = [reusableTiles anyObject];
if (tile) {
[reusableTiles removeObject:tile];
tile.frame = frame;
}
else {
tile = [[UIImageView alloc] initWithFrame:frame];
}
tile.image = image;
return tile;
}
Where reusableTiles is just an iVar of NSMutableSet type. You could then use this to load fetch any currently offscreen image views and quickly and easily bring them back into view.
Your layoutSubviews may look something like:
- (void)layoutSubviews {
[super layoutSubviews];
CGRect visibleBounds = [self bounds];
CGPoint contentArea = [self contentOffset];
//recycle all tiles that are not visible
for (GSVLineTileView *tile in [self subviews]) {
if (! CGRectIntersectsRect([tile frame], visibleBounds)) {
[reusableTiles addObject:tile];
[tile removeFromSuperview];
}
}
int col = firstVisibleColumn = floorf(CGRectGetMinX(visibleBounds)/tileSize.width);
lastVisibleColumn = floorf(CGRectGetMaxX(visibleBounds)/tileSize.width) ;
int row = firstVisibleRow = floorf(CGRectGetMinY(visibleBounds)/tileSize.height);
lastVisibleRow = floorf(CGRectGetMaxY(visibleBounds)/tileSize.height);
while(row <= lastVisibleRow)
{
col = firstVisibleColumn;
while (col <= lastVisibleColumn)
{
if(row < firstDisplayedRow || row > lastDisplayedRow || col < firstDisplayedColumn || col >lastDisplayedColumn)
{
UImageView* tile = [self dequeueReusableTileWithFrame:CGRectMake(tileSize.width*col, tileSize.height*row, tileSize.width, tileSize.height) andImage:YourImage];
[self addSubview:tile];
}
++col;
}
++row;
}
firstDisplayedColumn = firstVisibleColumn;
lastDisplayedColumn = lastVisibleColumn;
firstDisplayedRow = firstVisibleRow;
lastDisplayedRow = lastVisibleRow;
}
I used something similar to this to tile in areas of a line when I was working with an exceptionally large area of a scroll view and it seemed to work quite well. Sorry for any typos that I may have created when updating this for an image view instead of my custom tileView class.
I'm having some problems in my usage of the TiledScrollView from Apple (3_Tiling/Classes/TiledScrollView.m) where sometimes the tiles don't show as I scroll and other times they do show. To clarify, the problem I'm seeing is analogous to having a tableview list of 100 rows and only 10 rows are being displayed at a time. As you scroll through the list, sometimes one or more rows are blank and stay blank because once they're displayed on the screen there is no reloading to make sure the content is there. However once these blank rows go off screen and say you scroll back to them, they show up with the content.
It seems to be completely random with no discernible patterns to it's behaviour. I know the delegate method ((UIView *)tiledScrollView:(TiledScrollView *)tiledScrollView tileForRow:(int)row column:(int)column resolution:(int)resolution) is executing thru NSLog's.
My Question is:
1. Have you encountered this phenomenon and how did you solve it? or
2. My debugging skill are very rudimentary. If I wanted to isolate the problem by seeing whether the tile or subviews exists, or the imageView was not able to fetch the image or if its a rendering problem... how would I go about debugging this?
Note- the delegate method shown below is a stripped down version of the above tiledScrollView delegate method where I removed the row and resolution portions of the code since there is no need for it if I'm just scrolling horizontally.
- (UIView *)tiledScrollView:(HorizontalTiledScrollView *)tiledScrollView column:(int)column {
NSLog(#"+++ %s +++", __PRETTY_FUNCTION__);
// re-use a tile rather than creating a new one, if possible
UIView *tile = [tiledScrollView dequeueReusableTile];
if (!tile) {
// the scroll view will handle setting the tile's frame, so we don't have to worry about it
if (tiledScrollView == self.timeHour) {
tile = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, TIMEHOUR_COLUMN_WIDTH, TIMEHOUR_COLUMN_HEIGHT)] autorelease];
} else if (tiledScrollView == self.timeMinute) {
tile = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, TIMEMINUTE_COLUMN_WIDTH, TIMEMINUTE_COLUMN_HEIGHT)] autorelease];
}
// Some of the tiles won't be completely filled, because they're on the right or bottom edge.
// By default, the image would be stretched to fill the frame of the image view, but we don't
// want this. Setting the content mode to "top left" ensures that the images around the edge are
// positioned properly in their tiles.
[tile setContentMode:UIViewContentModeTopLeft];
}
for(UIView *subview in [tile subviews]) {
if (subview.tag != 3) {
[subview removeFromSuperview]; //remove all previous subviews in tile except tile annotation if present
}
}
UIImageView *imgView = [[UIImageView alloc] init];
UILabel *digitLabel;
// Add blank UIImageView as filler or UIImageView with PNG or UILabel if no PNG sized correctly and offsetted from tile's origin as subviews in the tile
if (tiledScrollView == self.timeHour) {
if (column < 1) {
imgView.frame = CGRectZero;
[tile addSubview:imgView];
[tile bringSubviewToFront:imgView];
} else {
int digitH = ((column - 1) % 12 + 1);
imgView.frame = CGRectMake(9, 0, 17, 21);
[imgView setContentMode:UIViewContentModeScaleToFill];
if ((imgView.image = [UIImage imageNamed:[NSString stringWithFormat:#"TimeHour_%02d.png", digitH]])) {
[tile addSubview:imgView];
[tile bringSubviewToFront:imgView];
} else {
// NSLog(#"No TimeHour_%02d.png", digitH);
digitLabel = [self makeDigitLabel:digitH frame:imgView.frame fontSize:14.0];
[tile addSubview:digitLabel];
[tile bringSubviewToFront:digitLabel];
}
}
} else if (tiledScrollView == self.timeMinute) {
// if (column % 2) {
// tile.backgroundColor = [UIColor redColor];
// } else {
// tile.backgroundColor = [UIColor blueColor];
// }
if (column < 1) {
imgView.frame = CGRectZero;
[tile addSubview:imgView];
[tile bringSubviewToFront:imgView];
} else {
int digitM = ((column - 1) % 60);
imgView.frame = CGRectMake(9, 0, 16, 15);
[imgView setContentMode:UIViewContentModeScaleToFill];
if ((imgView.image = [UIImage imageNamed:[NSString stringWithFormat:#"TimeMinute_%02d.png", digitM]])) {
[tile addSubview:imgView];
[tile bringSubviewToFront:imgView];
} else {
NSLog(#"No TimeMinute_%02d.png", digitM);
digitLabel = [self makeDigitLabel:digitM frame:imgView.frame fontSize:12.0];
[tile addSubview:digitLabel];
[tile bringSubviewToFront:digitLabel];
}
}
}
}
[imgView release];
NSLog(#"Tile: %d",[tile.subviews count]);
return tile;
}
Hope it's clear.
Thanks for helping,
Hiren
I finally solved this!
The issue wasn't in the code posted above. It was in the layoutSubviews method of Apple's TiledScrollView. There is a line of code that calculates the maximum column shown below (max row has a similar calculation)
int lastNeededCol = MIN(maxCol, floorf(CGRectGetMaxX(visibleBounds) / scaledTileWidth));
In my case, this formula calculates one extra column than is needed and this column tile ends up sitting off screen. This is fine when you're not scrolling around and setting animated to NO. But when you do scroll around and/or set animated to YES in scrollview setContentOffset method call, you will sometimes end up with a missing tile because of the delay due to animation or if you scrolled really slowly. The animation or moving really slowly causes the scrollview to detect there is a movement and thus calls the layoutSubviews method where a line of code checks to see which tiles are visible and drops non-visible tiles. Now if you did this just right, then the extra tile created earlier gets dropped because its still off-screen and is never created again until the tile has moved far enough off-screen triggering a reload of that tile.
The fix I did was to change the above line to:
int lastNeededCol = MIN(maxCol, floorf((CGRectGetMaxX(visibleBounds)-0.1) / scaledTileWidth));
This new formula calculates the right number of columns of tiles needed to be displayed on screen thereby eliminating the whole thing of dropping extra tiles sitting off-screen.
I create an example code on github that helps demonstrates this.
https://github.com/hmistry/TiledScrollViewDebug
Is it possible to change the height of UIPickerView? Some applications seem to have shorter PickerViews but setting a smaller frame doesn't seem to work and the frame is locked in Interface Builder.
It seems obvious that Apple doesn't particularly invite mucking with the default height of the UIPickerView, but I have found that you can achieve a change in the height of the view by taking complete control and passing a desired frame size at creation time, e.g:
smallerPicker = [[UIPickerView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 120.0)];
You will discover that at various heights and widths, there are visual glitches. Obviously, these glitches would either need to be worked around somehow, or choose another size that doesn't exhibit them.
None of the above approaches work in iOS 4.0
The pickerView's height is no longer re-sizable. There is a message which gets dumped to console if you attempt to change the frame of a picker in 4.0:
-[UIPickerView setFrame:]: invalid height value 66.0 pinned to 162.0
I ended up doing something quite radical to get the effect of a smaller picker which works in both OS 3.xx and OS 4.0. I left the picker to be whatever size the SDK decides it should be and instead made a cut-through transparent window on my background image through which the picker becomes visible. Then simply placed the picker behind (Z Order wise) my background UIImageView so that only a part of the picker is visible which is dictated by the transparent window in my background.
There are only three valid heights for UIPickerView (162.0, 180.0 and 216.0).
You can use the CGAffineTransformMakeTranslation and CGAffineTransformMakeScale functions to properly fit the picker to your convenience.
Example:
CGAffineTransform t0 = CGAffineTransformMakeTranslation (0, pickerview.bounds.size.height/2);
CGAffineTransform s0 = CGAffineTransformMakeScale (1.0, 0.5);
CGAffineTransform t1 = CGAffineTransformMakeTranslation (0, -pickerview.bounds.size.height/2);
pickerview.transform = CGAffineTransformConcat (t0, CGAffineTransformConcat(s0, t1));
The above code change the height of picker view to half and re-position it to the exact (Left-x1, Top-y1) position.
Try:
pickerview.transform = CGAffineTransformMakeScale(.5, 0.5);
In iOS 4.2 & 4.3 the following works:
UIDatePicker *datePicker = [[UIDatePicker alloc] init];
datePicker.frame = CGRectMake(0, 0, 320, 180);
[self addSubview:datePicker];
The following does not work:
UIDatePicker *datePicker = [[UIDatePicker alloc] initWithFrame:CGRectMake(0, 0, 320, 180)];
[self addSubview:datePicker];
I have an app that is in the app store with a 3 line date picker. I thought the height change may have been prevented because you see the text under the date picker's border, but this happens to the normal 216 height date picker too.
Which is the bug? Your guess is as good as mine.
Also there are 3 valid heights for UIDatePicker (and UIPickerView) 162.0, 180.0, and 216.0. If you set a UIPickerView height to anything else you will see the following in the console when debugging on an iOS device.
2011-09-14 10:06:56.180 DebugHarness[1717:707] -[UIPickerView setFrame:]: invalid height value 300.0 pinned to 216.0
As of iOS 9, you can freely change UIPickerView's width and height. No need to use the above mentioned transform hacks.
I have found that you can edit the size of the UIPickerView - just not with interface builder. open the .xib file with a text editor and set the size of the picker view to whatever you want. Interface builder does not reset the size and it seems to work. I'm sure apple locked the size for a reason so you'll have to experiment with different sizes to see what works.
Advantages:
Makes setFrame of UIPickerView behave like it should
No transform code within your UIViewController
Works within viewWillLayoutSubviews to rescale/position the UIPickerView
Works on the iPad without UIPopover
The superclass always receives a valid height
Works with iOS 5
Disadvantages:
Requires you to subclass UIPickerView
Requires the use of pickerView viewForRow to undo the transformation for the subViews
UIAnimations might not work
Solution:
Subclass UIPickerView and overwrite the two methods using the following code. It combines subclassing, fixed height and the transformation approach.
#define FIXED_PICKER_HEIGHT 216.0f
- (void) setFrame:(CGRect)frame
{
CGFloat targetHeight = frame.size.height;
CGFloat scaleFactor = targetHeight / FIXED_PICKER_HEIGHT;
frame.size.height = FIXED_PICKER_HEIGHT;//fake normal conditions for super
self.transform = CGAffineTransformIdentity;//fake normal conditions for super
[super setFrame:frame];
frame.size.height = targetHeight;
CGFloat dX=self.bounds.size.width/2, dY=self.bounds.size.height/2;
self.transform = CGAffineTransformTranslate(CGAffineTransformScale(CGAffineTransformMakeTranslation(-dX, -dY), 1, scaleFactor), dX, dY);
}
- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
//Your code goes here
CGFloat inverseScaleFactor = FIXED_PICKER_HEIGHT/self.frame.size.height;
CGAffineTransform scale = CGAffineTransformMakeScale(1, inverseScaleFactor);
view.transform = scale;
return view;
}
An easy way to change the visible height of a picker view is to embed the picker in a UIView, adjust the parent view's height to the height you want to see of the picker, then enable "Clip Subviews" in Interface Builder on the parent UIView or set view.clipsToBounds = true in code.
I wasn't able to follow any of the above advice.
I watched multiple tutorials and found this one the most beneficial:
I added the following code to set the new height inside the "viewDidLoad" method, which worked in my app.
UIPickerView *picker = [[UIPickerView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 120.0)];
[self.view addSubview:picker];
picker.delegate = self;
picker.dataSource = self;
Hope this was helpful!
This has changed a lot in iOS 9 (in iOS 8 it's pretty similar to what we're seeing here). If you can afford to target iOS 9 only, then you resize the UIPickerView as you see fit, by setting its frame. Good!
Here it is from iOS 9 Release Notes
UIPickerView and UIDatePicker are now resizable and
adaptive—previously, these views would enforce a default size even if
you attempted to resize them. These views also now default to a width
of 320 points on all devices, instead of to the device width on
iPhone.
Interfaces that rely on the old enforcement of the default size will
likely look wrong when compiled for iOS 9. Any problems encountered
can be resolved by fully constraining or sizing picker views to the
desired size instead of relying on implicit behavior.
I am working with ios 7, Xcode 5. I was able to adjust the height of date picker indirectly by enclosing it in a view. The container views height can be adjusted.
Create a view in IB or code. Add your picker as a subview of this view. Resize the view. This is easiest to do in IB. Create constraints from the view to its superview and from the picker to this new view.
Since the Picker curves around it spills out over the top and bottom of the view. You can see in IB when you add top and bottom constraints from the picker to the view it shows a standard space something like 16 points above and below the superview container. Set the view to clip it if you don't want this behaviour (ugly warning).
Here's what it looks like at 96 points high on an iPhone 5. The picker with the spillover is about 130 points high. Pretty skinny!
I'm using this in my project to prevent the picker from spreading out to an unnecessary height. This technique trims it down and forces a tighter spill over. It actually looks slicker to be a bit more compact.
Here's an image of the view showing the spillover.
Here's the IB constraints I added.
As mentioned above UIPickerView is now resizable. I just want to add though that if you want to change the pickerView's height in a tableView Cell, I didn't have any success with setting the height anchor to a constant. However, using lessThanOrEqualToConstant seems to work.
class PickerViewCell: UITableViewCell {
let pickerView = UIPickerView()
func setup() {
// call this from however you initialize your cell
self.contentView.addSubview(self.pickerView)
self.pickerView.translatesAutoresizingMaskIntoConstraints = false
let constraints: [NSLayoutConstraint] = [
// pin the pickerView to the contentView's layoutMarginsGuide
self.pickerView.leadingAnchor.constraint(equalTo: self.contentView.layoutMarginsGuide.leadingAnchor),
self.pickerView.topAnchor.constraint(equalTo: self.contentView.layoutMarginsGuide.topAnchor),
self.pickerView.trailingAnchor.constraint(equalTo: self.contentView.layoutMarginsGuide.trailingAnchor),
self.pickerView.bottomAnchor.constraint(equalTo: self.contentView.layoutMarginsGuide.bottomAnchor),
// set the height using lessThanOrEqualToConstant
self.pickerView.heightAnchor.constraint(lessThanOrEqualToConstant: 100)
]
NSLayoutConstraint.activate(constraints)
}
}
Even thought it is not resizing, another trick may help in the situation when the UIPicker is located at the bottom of the screen.
One can try moving it slightly downwards, but the central row should remain visible. This will help reveal some space above the picker since bottom rows will be offscreen.
I repeat that this is not the way of changing UIPicker view's height but some idea on what you can do if all other attempts fail.
Ok, after struggling for a long time with the stupid pickerview in iOS 4, I've decided to change my control into simple table:
here is the code:
ComboBoxView.m = which is actually looks more like pickerview.
//
// ComboBoxView.m
// iTrophy
//
// Created by Gal Blank on 8/18/10.
//
#import "ComboBoxView.h"
#import "AwardsStruct.h"
#implementation ComboBoxView
#synthesize displayedObjects;
#pragma mark -
#pragma mark Initialization
/*
- (id)initWithStyle:(UITableViewStyle)style {
// Override initWithStyle: if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
if ((self = [super initWithStyle:style])) {
}
return self;
}
*/
#pragma mark -
#pragma mark View lifecycle
/*
- (void)viewDidLoad {
[super viewDidLoad];
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem;
}
*/
/*
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
}
*/
/*
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
}
*/
/*
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
}
*/
/*
- (void)viewDidDisappear:(BOOL)animated {
[super viewDidDisappear:animated];
}
*/
/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// Return YES for supported orientations
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/
#pragma mark -
#pragma mark Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
// Return the number of sections.
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
// Return the number of rows in the section.
self.tableView.separatorStyle = UITableViewCellSeparatorStyleSingleLine;
return [[self displayedObjects] count];
}
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *MyIdentifier = [NSString stringWithFormat:#"MyIdentifier %i", indexPath.row];
UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:MyIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:MyIdentifier] autorelease];
//cell.contentView.frame = CGRectMake(0, 0, 230.0,16);
UILabel *label = [[[UILabel alloc] initWithFrame:CGRectMake(0, 5, 230.0,19)] autorelease];
VivatAwardsStruct *vType = [displayedObjects objectAtIndex:indexPath.row];
NSString *section = [vType awardType];
label.tag = 1;
label.font = [UIFont systemFontOfSize:17.0];
label.text = section;
label.textAlignment = UITextAlignmentCenter;
label.baselineAdjustment = UIBaselineAdjustmentAlignCenters;
label.adjustsFontSizeToFitWidth=YES;
label.textColor = [UIColor blackColor];
//label.autoresizingMask = UIViewAutoresizingFlexibleHeight;
[cell.contentView addSubview:label];
//UIImage *image = nil;
label.backgroundColor = [UIColor whiteColor];
//image = [awards awardImage];
//image = [image imageScaledToSize:CGSizeMake(32.0, 32.0)];
//[cell setAccessoryType:UITableViewCellAccessoryDisclosureIndicator];
//UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
//cell.accessoryView = imageView;
//[imageView release];
}
return cell;
}
/*
// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
// Return NO if you do not want the specified item to be editable.
return YES;
}
*/
/*
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete the row from the data source
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES];
}
else if (editingStyle == UITableViewCellEditingStyleInsert) {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}
*/
/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath {
}
*/
/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath {
// Return NO if you do not want the item to be re-orderable.
return YES;
}
*/
#pragma mark -
#pragma mark Table view delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// Navigation logic may go here. Create and push another view controller.
/*
<#DetailViewController#> *detailViewController = [[<#DetailViewController#> alloc] initWithNibName:#"<#Nib name#>" bundle:nil];
// ...
// Pass the selected object to the new view controller.
[self.navigationController pushViewController:detailViewController animated:YES];
[detailViewController release];
*/
}
#pragma mark -
#pragma mark Memory management
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Relinquish ownership any cached data, images, etc that aren't in use.
}
- (void)viewDidUnload {
// Relinquish ownership of anything that can be recreated in viewDidLoad or on demand.
// For example: self.myOutlet = nil;
}
- (void)dealloc {
[super dealloc];
}
#end
Here is the .h file for that:
//
// ComboBoxView.h
// iTrophy
//
// Created by Gal Blank on 8/18/10.
//
#import <UIKit/UIKit.h>
#interface ComboBoxView : UITableViewController {
NSMutableArray *displayedObjects;
}
#property (nonatomic, retain) NSMutableArray *displayedObjects;
#end
now, in the ViewController where I had Apple UIPickerView I replaced with my own ComboBox view and made it size what ever I wish.
ComboBoxView *mypickerholder = [[ComboBoxView alloc] init];
[mypickerholder.view setFrame:CGRectMake(50, 220, 230, 80)];
[mypickerholder setDisplayedObjects:awardTypesArray];
that's it, now the only thing is left is to create a member variable in the combobox view that will hold current row selection, and we are good to go.
Enjoy everyone.
You can not generally do it in xib or setting frame programtically but if you open its parent xib as source and change height from there then it works.Right click the xib within which pickerview is contained,Search pickerview and you can find height,width etc in that tag,Change height there then save file.
<pickerView contentMode="scaleToFill" id="pai-pm-hjZ">
<rect key="frame" x="0.0" y="41" width="320" height="100"/>
<autoresizingMask key="autoresizingMask" widthSizable="YES" flexibleMaxY="YES"/>
<connections>
<outlet property="dataSource" destination="-1" id="Mo2-zp-Sl4"/>
<outlet property="delegate" destination="-1" id="nfW-lU-tsU"/>
</connections>
</pickerView>
As far as I know, it's impossible to shrink the UIPickerView. I also haven't actually seen a shorter one used anywhere. My guess is that it was a custom implementation if they did manage to shrink it.
If you want to create your picker in IB, you can post-resize it to a smaller size. Check to make sure it still draws correctly though, as there comes a point where it looks heinous.
Swift: You need to add a subview with clip to bounds
var DateView = UIView(frame: CGRectMake(0, 0, view.frame.width, 100))
DateView.layer.borderWidth=1
DateView.clipsToBounds = true
var myDatepicker = UIDatePicker(frame:CGRectMake(0,-20,view.frame.width,162));
DateView.addSubview(myDatepicker);
self.view.addSubview(DateView)
This should add a clipped 100 height date picker in the top of the view controller.
My trick: use datepicker's mask layer to make datePicker some part visible. as you see just like change the datepicke's frame.
- (void)timeSelect:(UIButton *)timeButton {
UIDatePicker *timePicker = [[UIDatePicker alloc] initWithFrame:CGRectMake(0, 0, kScreenWidth, 550)];
timePicker.backgroundColor = [UIColor whiteColor];
timePicker.layer.mask = [self maskLayerWithDatePicker:timePicker];
timePicker.layer.masksToBounds = YES;
timePicker.datePickerMode = UIDatePickerModeTime;
[self.view addSubview:timePicker];
}
- (CALayer *)maskLayerWithDatePicker:(UIDatePicker *)datePicker {
CAShapeLayer *shapeLayer = [[CAShapeLayer alloc] init];
UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, datePicker.width*0.8, datePicker.height*0.8) cornerRadius:10];
shapeLayer.path = path.CGPath;
return shapeLayer;
}
I use a mask layer to change it's display size
// swift 3.x
let layer = CALayer()
layer.frame = CGRect(x: 0,y:0, width: displayWidth, height: displayHeight)
layer.backgroundColor = UIColor.red.cgColor
pickerView.layer.mask = layer
Embed in a stack view. Stack view is a component recently added by Apple in their iOS SDK to reflect grid based implementations in java script web based front end libraries such as bootstrap.
After a long day of scratching my head, I've found something that works for me. The codes below will recreate the UIDatePicker everytime the user change the phone orientation. This will remove whatever glitches that the UIDatePicker have after an orientation change.
Since we are recreating the UIDatePicker, we need an instance variable that will keep the selected date value. The codes below are tested on iOS 4.0.
#interface AdvanceDateViewController : UIViewController<UIPickerViewDelegate> {
UIDatePicker *datePicker;
NSDate *date;
}
#property (nonatomic, retain) UIDatePicker *datePicker;
#property (nonatomic, retain) NSDate *date;
-(void)resizeViewWithOrientation:(UIInterfaceOrientation) orientation;
#end
#implementation AdvanceDateViewController
#synthesize datePicker, date;
- (void)viewDidLoad {
[super viewDidLoad];
[self resizeViewWithOrientation:self.interfaceOrientation];
}
-(void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];
[self resizeViewWithOrientation:self.interfaceOrientation];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
return YES;
}
-(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration{
[super willRotateToInterfaceOrientation:toInterfaceOrientation duration:duration];
[self resizeViewWithOrientation:toInterfaceOrientation];
}
-(void)resizeViewWithOrientation:(UIInterfaceOrientation) orientation{
[self.datePicker removeFromSuperview];
[self.datePicker removeTarget:self action:#selector(refreshPickupDate) forControlEvents:UIControlEventValueChanged];
self.datePicker = nil;
//(Re)initialize the datepicker, thanks to Apple's buggy UIDatePicker implementation
UIDatePicker *dummyDatePicker = [[UIDatePicker alloc] init];
self.datePicker = dummyDatePicker;
[dummyDatePicker release];
[self.datePicker setDate:self.date animated:YES];
[self.datePicker addTarget:self action:#selector(refreshPickupDate) forControlEvents:UIControlEventValueChanged];
if(UIInterfaceOrientationIsLandscape(orientation)){
self.datePicker.frame = CGRectMake(0, 118, 480, 162);
} else {
self.datePicker.frame = CGRectMake(0, 200, 320, 216);
}
[self.view addSubview:self.datePicker];
[self.view setNeedsDisplay];
}
#end
stockPicker = [[UIPickerView alloc] init];
stockPicker.frame = CGRectMake(70.0,155, 180,100);
If You want to set the size of UiPickerView. Above code is surely gonna work for u.
In iOS 5.0, I got the following to work:
UIDatePicker *picker = [[UIDatePicker alloc] init];
picker.frame = CGRectMake(0.0, 0.0, 320.0, 160.0);
This created a date picker like the one Apple uses in the Calendar app when creating a new event in landscape mode. (3 rows high instead of 5.) This didn't work when I set the frame within the initWithFrame: method, but so far works when setting it using a separate method.
for iOS 5:
if you take a quick look at the UIPickerView Protocol Reference
you'll find
– pickerView:rowHeightForComponent:
– pickerView:widthForComponent:
I think is the first one you're looking for