I'm trying to create a NSImageView programmatically as a subview of another NSImageView when awakeFromNib is called.
My code is as follows (Fader is defined in MyImageView.h):
#implementation MyImageView
- (void)awakeFromNib {
Fader = [NSImageView initWithFrame: [self frame]];
}
I get the warning message "NSImageView may not respong to +initWithFrame". When I build, the app simply frizzes without showing anything, and I have to "force quit".
What am I doing wrong?
You’ve forgotten to send +alloc in order to allocate the object. Change that line to:
Fader = [[NSImageView alloc] initWithFrame: [self frame]];
Related
I have an xib file containing a custom cell. I'm trying to access the height of an object created in customCell.m.
Here is my code:
customCell.m
- (void)awakeFromNib
{
self.label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 50, 200)];
[self.label setText:#"This is a label"];
[self.myView addSubview:self.label];
NSLog(#"%f", self.label.frame.size.height); // Results: 200.0000
}
mainViewController.m
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
customCell *cellVC = [[cutsomCell alloc] init];
NSLog(#"%f, %f", cellVC.label.frame.size.height); // Results: 0.0000
}
awakeFromNib is called when all file owners outlets and properties are set. Things are not wired up (in terms of frames/layout) in viewDidLoad.
awakeFromNib is called after viewDidLoad, that is why you see the difference.
Sorry, this doesn't work. You are creating your customCell via alloc/init in code. AwakeFromNib is only called for objects defined in a nib file.
You probably need to define your customCell in a separate nib file, and load that nib file through + (BOOL)loadNibNamed:(NSString *)aNibName owner:(id)owner or similar.
I have an app with several SKScenes. To keep it snappy, I have a single UIViewController, that handles 1 SKView.
I'm trying to add a UICollectionView to one of the SKScenes. However the problem comes when I try to set the delegate for the collection view to the SKScene initialising it.
I initialise it here:
- (id)initWithSize:(CGSize)size
{
if (self = [super initWithSize:size]) {
//Initialise collectionView
UICollectionViewLayout *layout = [[UICollectionViewLayout alloc] init];
_collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, size.width, size.height) collectionViewLayout:layout];
_collectionView.delegate = self;
_collectionView.dataSource = self;
[_collectionView setBackgroundColor:[UIColor redColor]];
}
return self;
}
After initialising, I add the collection view as a subview of the UIViewController's view by calling:
- (void)didMoveToView:(SKView *)view
{
[self.view addSubview:_collectionView];
}
But the delegate or datasource methods aren't called. I've set up the header:
#interface BrowseScene : SKScene <UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout>
I'm guessing that despite setting self as the delegate, once the collection view is added, it is added as a subview of the UIViewController's SKView, and therefore has no reference to the SKScene that initialised it. I tried calling:
_collectionView.delegate = self.view.scene;
But I get a compiler error saying SKScene is an incompatible type for UICollectionViewDelegate.
So my question is, how best to approach this?
It turns out, the problem lay in how I was initialising the UICollectionView, not where. And it's perfectly ok to set an SKScene as the delegate class.
The main reason the delegates weren't being called was because I'd initialised the collectionView with an empty layout object (as UICollectionViewLayout is just an abstract class). I initialised with a standard UICollectionViewFlowLayout instead, and the methods were then called when the class initialised.
I was also missing a call to
[_collectionView registerClass:[collectionViewCell class] forCellWithReuseIdentifier:#"collectionViewCell"];
(In the complete code, I had calls to reloadData, so that wasn't the problem here).
I have an iPad app, using Storyboards, XCode 4.6 and iOS 6.1. I have a scene that contains a UIViewController. Inside that UIViewController, I have a UIScrollController, all created using IB. Programmatically, in viewDidLoad I created two (2) UIViews (one called subViewGrid, the other called subViewData) and added them to the UIViewController; they both display correctly in the Simulator. Here's the code:
- (void)viewDidLoad {
[super viewDidLoad];
// notify me when calendar has been tapped and CFGregorianDate has been updated
[[NSNotificationCenter defaultCenter] removeObserver:self];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(calendarTapNotification:)
name:#"calendarDateSelected" object:nil ];
// UIScrollVIew settings
CGSize scrollableSize = CGSizeMake(760, 1379); // set size of scheduleView
[self.schedScrollView setContentSize:scrollableSize];
self.schedScrollView.contentInset = UIEdgeInsetsMake(0,0,44,44); // allow for scroll bar
self.schedScrollView.directionalLockEnabled = YES; // prevents diagonal scrolling
// create a sub-view to hold the appointment GRID
CGRect frame = CGRectMake(0,0,760,1390); // 110,48,760,1390
subViewGrid = [[UIView alloc] initWithFrame:frame];
subViewGrid.tag = 12; // use tag to get correct sub-view
subViewGrid.backgroundColor = [UIColor grayColor];
subViewGrid.alpha = 1.0; // make it opaque
[self.schedScrollView addSubview:subViewGrid];
// create a sub-view to hold the appointment DATA
frame = CGRectMake(110,48,670,750);
subViewData = [[UIView alloc] initWithFrame:frame];
subViewData.tag = 22; // use tag to get correct sub-view
subViewData.backgroundColor = [UIColor redColor];
subViewData.alpha = 0.2; // make it sort of transparent
[self.schedScrollView addSubview:subViewData];
[self.subViewGrid setNeedsDisplay]; // **** UPDATED ****
}
Here is the .h file contents for the UIViewController:
#interface CalendarViewController : UIViewController {
UIView *subViewGrid;
UIView *subViewData;
}
#property (strong, nonatomic) IBOutlet UIScrollView *schedScrollView;
- (void) calendarTapNotification:(NSNotification *) notification;
-(NSDate *)beginningOfDay:(NSDate *)date;
-(NSDate *)endOfDay:(NSDate *)date;
#end
In my drawRect method, I have some code that is supposed to draw a "grid" on the subViewGrid. The problem is drawRect never gets called.`
I have read the UIView Programmer's Guide and looked in SO and did a Google search, but found nothing that addresses the issue, which is: why won't [self.subViewGrid setNeedsDisplay] call drawRect from where I have it placed?
Your view controller needs to call setNeedsDisplay for the view it controls, not for itself. So, you want
[self.subViewGrid setNeedsDisplay]
This is just an error in your reading the documentation. Understanding the documentation is critical for objective-C programming so I'll try to help you get a grasp of it.
If you look at the documentation for setNeedsDisplay you will see that it is either a CALayer or UIView class method. If you then look at inheritance, you will see that UIView is UIResponder:NSObject and CALayer is NSObject. None of these inherit from UIViewController which is why you are getting the error. You need to call [self.subViewGrid setNeedsDisplay]
I have a strange problem that I've never encountered before,
I have data in my viewController that I want to display in a UIView.
It's an iPad App which involve a SplitView Controller, when I click on an element within the table view (masterView) it execute a function in my detailViewController (via a protocol).
A function is executed which launch a UIView and send data to it:
myController:
- (void)SelectionChanged:(DocumentInfo*)document_info withDocu:(Document *)document{
DocumentView *viewDoc=[[DocumentView alloc]initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height)];
viewDoc.doc=document;
viewDoc.doc_info=document_info;
[viewDoc setBackgroundColor:[UIColor whiteColor]];
[self.view addSubview:viewDoc];
}
DocumentView.h
#import <UIKit/UIKit.h>
#import "Document.h"
#import "DocumentInfo.h"
#class Document;
#class DocumentInfo;
#interface DocumentView : UIView
#property(strong,nonatomic) Document *doc;
#property(strong,nonatomic) DocumentInfo *doc_info;
#end
DocumentView.m
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
UILabel *titreDoc=[[UILabel alloc] initWithFrame:CGRectMake(20, 32, 339, 21)];
titreDoc.textColor = [self makeColorRGB_RED:66 GREEN:101 BLUE:149];
titreDoc.font = [UIFont fontWithName:#"System" size:(24.0)];
[self addSubview:titreDoc];
NSLog(#"%# - %#",doc,doc_info);
titreDoc.text=#"Nouveau Document";
}
return self;
}
My view is well displayed (I mean the label appear) but impossible to get the data which would have been passed to it... (the NSLog print (null) (null) )
Anybody know the reason why?
The problem seems pretty straight forward. You initialize your view (which means that you run - (id)initWithFrame:(CGRect)frame) and after that you're setting the data, so it's normal that you see null values into your init method because the ivars have not being set yet. What you could do is to modify your init method in order to construct your view taking into account these ivars. Something like this perhaps:
- (id)initWithFrame:(CGRect)frame doc:(Document *)doc docInfo:(DocumentInfo *)docInfo;
ps. If you choose to make your custom init method do not forget to call the designated initializer (-initWithFrame:) before any customization.
The reason the NSLog prints null is because the doc and doc_info are nil when the initWithFrame method is called. The doc and doc_info properties are set after the initWithFrame method is called in selectionChanged: method. Add the NSLog function after line 3 in selectionChanged method like this:
- (void)SelectionChanged:(DocumentInfo*)document_info withDocu:(Document *)document{
DocumentView *viewDoc=[[DocumentView alloc]initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height)];
viewDoc.doc=document;
viewDoc.doc_info=document_info;
NSLog(#"%# - %#",doc,doc_info);
[viewDoc setBackgroundColor:[UIColor whiteColor]];
[self.view addSubview:viewDoc];
}
I'm trying to lay out some images in code using addSubview, and they are not showing up.
I created a class (myUIView) that subclasses UIView, and then changed the class of the nib file in IB to be myUIView.
Then I put in the following code, but am still getting a blank grey screen.
- (id)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
// Initialization code
[self setupSubviews];
}
return self;
}
- (void)setupSubviews
{
self.backgroundColor = [UIColor blackColor];
UIImageView *black = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"black.png"]];
black.center = self.center;
black.opaque = YES;
[self addSubview:black];
[black release];
}
yes, just implement initWithCoder.
initWithFrame is called when a UIView is created dynamically, from code.
a view that is loaded from a .nib file is always instantiated using initWithCoder, the coder takes care of reading the settings from the .nib file
i took the habit to do the initialization in a separate method, implementing both initWithCode and initWithFrame (and my own initialization methods when required)
try implementing initWithCoder: sometimes I've had trouble with IB and initWithFrame:
or at least add a logging call to see if your init method is executed