I have a few custom UIView objects that all handle drawing like this:
- (void)drawRect:(CGRect)rect {
// ^ I init the layers 1 and 2
[self.layer insertSublayer:layer1 atIndex:0]; // 1 or more
[self.layer insertSublayer:layer2 atIndex:1];
}
They also have a - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event; with nothing else inside but a NSLog.
I add them all inside my main ViewController like so:
- (void)viewDidLoad
{
[super viewDidLoad];
CustomView *myViewWith1Layer = [[CustomView alloc] initWithFrame:CGRectMake(20, 20, 440, 260)];
[self.view addSubview:myViewWith1Layer];
CustomViewLayered *myViewWith2Layer = [[CustomViewLayered alloc] initWithFrame:CGRectMake(40, 260, 200, -120)];
[self.view addSubview:myViewWith2Layers];
}
When I run my app, if I tap on a view that has only a single layer - I get my NSLog to show, and everything's fine. If, on the other hand, I tap on views with 1+ layers, the app crashes (objc_msgSend log shows up with "EXC_BAD_ACCES (code=1, address=..."). I guess this is somehow related with ARC, which I have enabled.
How do I add multiple layers to a view, without it being messed up by ARC?
I don't think that this is an ARC problem, but creating and inserting the layers in drawRect
is wrong. This should be done (only once) in the init method of the view, e.g. in initWithFrame.
In my case, the solution was definitely related to ARC.
When initialising my delegates, I immediately assigned them to the layer.delegate property, and ARC would remove the object from existence immediately after that.
So for each layer, I add a strong #property (strong, nonatomic) delegatesClass *delegatesName and initialise straight to the property. After that, I assign the layer.delegate = self.delegatesName.
This did solve the issue, although I'm not sure if it is the right way to do things.
Related
my didAddSubview is not being called.
This is what I am doing.
In my viewController
- (void)viewDidLoad {
[super viewDidLoad];
SomeView *view = [[SomeView alloc] initWithFrame:CGRectMake(0.0, 0.0, CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame))];
[self.view addSubview:view];
}
Where my SomeView is a UI view (.h file)
#import <UIKit/UIKit.h>
#interface DyteMeetingView : UIView
#end
in which I have didAddSubview like this
- (void)didAddSubview:(UIView *)subview{
[super didAddSubview:subview];
[self someFunc];
}
I placed debugger in didAddSubview but the debugger never reaches here and hence [self someFunc]; is also not called.
Since didAddSubview is a lifecycle method for UI view, I am also not calling it from anywhere.
Can someone help me in figure out the concept I missed out on/what I could be doing wrong?
PS: I don't have any xib file for UIView.
PS: Intentionally added swift tag as well since there isn't large chunk of code and I am confident that swift developers would be able to understand the question/code and might be able to help me out.
didAddSubview in SomeView will be called when a sub view is added to an instance of SomeView, but that isn't what you are doing here. You are adding a SomeView as a subview of another view.
You want didMoveToSuperview; in this method you can use the superview property of self to identify the view that it moved to.
The didAddSubview will be called in viewController.view, instead of your SomeView, because you using viewController.view.addSubview(subview)
I'm trying to do some CALayer stuff on a UIButton that resides inside a uitableviewcell.
I've imported but the CALayer manipulation is not working.
When I moved it to cellForRowAtIndexPath method it works fine.
I do want to make the change once inside the class of the cell itself and not inside the table creation table.
Do you have any ideas ?
By the way, I do see the NSLog text on the init (so I know it entered the block).
Thanks !
- (id)initWithCoder:(NSCoder *)aDecoder {
self = [super initWithCoder:aDecoder];
if (self) {
NSLog(#"STARTED coder init in testResultCell");
[[self.bubbleMore layer] setMasksToBounds:YES];
[[self.bubbleMore layer] setBorderWidth:3.0f];
[[self.bubbleMore layer] setBorderColor:[UIColor blueColor].CGColor];
[[self.bubbleMore layer] setCornerRadius:20.0f];
}
return self;
}
Move the code to awakeWithNib. Your outlets won't be connected yet in initWithCoder. From Apple's documentation:
When an object receives an awakeFromNib message, it is guaranteed to have all its outlet instance variables set.
User interface objects are not available until viewDidLoad is called, which actually loads controls from your xib or Storyboard. Please move your code to viewDidLoad and it should work just fine.
If you add a breakpoint and look at the self.bubbleMore, it is going to be nil in initWithCode function.
I am designing a custom view controller in interface builder with a XIB file and I have a custom UIView subclass that I want to add to my view controller. Here is how I've put my custom view into the view controller:
My TonerEffectButtonView class is a subclass of UIView (and has nothing to do with UIButton) and here is my code for it:
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
-(void)prepareWithSelector:(SEL)selector onTarget:(id)targ withFilter:(GPUImageFilter*)filter{
self.gpuImageView = [[GPUImageView alloc] initWithFrame:self.frame];
UITapGestureRecognizer *gesture = [[UITapGestureRecognizer alloc] initWithTarget:targ action:selector];
[self addGestureRecognizer:gesture];
selectedFilter = filter;
[filter addTarget:self.gpuImageView];
[self setNeedsDisplay];
}
- (void)drawRect:(CGRect)rect
{
[super drawRect:rect];
}
initWithFrame: is not called anyway as I'm creating the view through a XIB, and I don't need any customization in initWithCoder: so I haven't implemented it. I have a GPUImageView (that is a part of a library that I'm using) that I'm creating programatically inside my view, and adding camera input to it (if you ask what happens in the prepare method). Prepare method is called from outside, and I've verified my UIView's frame is correct when it is called. I have a breakpoint on [super drawRect:rect]; and it never gets called, and when I run the program, my custom view is not displayed, nor does receive touch events (but prepare method DOES get called so the instance is created with the correct frame). It's like it has never been put there in interface builder. What could be the cause of this? I've seen many posts about this, and they mostly refer to creating views programatically and indicating problems with 'initWithFrame:'. But I have nothing to do with that method, and I want to use the interface builder/XIB couple, please don't advice me to create the view controller programatically. What could be the cause of it?
Thanks,
Can.
UPDATE: I can verify that -(void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx is also not called in any way.
Ok, I've found the answer. First, I've tried to add another instance programatically, and I've found out that it has autoresizing mask set to none, whereas my original instance has it set to W+H. This clue made me realize that in fact, I was forgetting to add my GPUImageView instance as a subview into my custom view. I've added it, and it worked.
I have some custom appearance properties in my view class (a descendant of UIView). I want to customize the view appearance according to these properties, but I can’t do that inside the initializer, since the values set using [[MyClass appearance] setFoo:…] aren’t in effect at that point:
#interface View : UIView
#property(strong) UIColor *someColor UI_APPEARANCE_SELECTOR;
#end
#implementation View
#synthesize someColor;
// Somewhere in other code before the initializer is called:
// [[View appearance] setSomeColor:[UIColor blackColor]];
- (id) initWithFrame: (CGRect) frame
{
self = [super initWithFrame:frame];
NSLog(#"%#", someColor); // nil
return self;
}
#end
They are already set in layoutSubviews, but that’s not a good point to perform the view customizations, since some customizations may trigger layoutSubviews again, leading to an endless loop.
So, what’s a good point to perform the customizations? Or is there a way to trigger the code that applies the appearance values?
One possible workaround is to grab the value directly from the proxy:
- (id) initWithFrame: (CGRect) frame
{
self = [super initWithFrame:frame];
NSLog(#"%#", [[View appearance] someColor); // not nil
return self;
}
Of course this kills the option to vary the appearance according to the view container and is generally ugly. Second option I found is to perform the customizations in the setter:
- (void) setSomeColor: (UIColor*) newColor
{
someColor = newColor;
// do whatever is needed
}
Still I’d rather have some hook that gets called after the appearance properties are set.
Why not wait until
- (void)willMoveToSuperview:(UIView *)newSuperview {
[super willMoveToSuperview:newSuperview];
if (newSuperview) {
... code here ...
}
}
if it's giving you trouble?
I believe UIAppearance properties are applied to a view when it is being added into a view hierarchy. So presumably you could access the set properties in UIView didMoveToSuperview.
Caveat: I am using Swift 2, so not sure about earlier versions of Swift / Objective-C. But I have found that didMoveToSuperview() will not work. The properties are available in layoutSubviews(), but that's not a great place to do anything like this (since it can be called more than once). The best place to access these properties in the lifeCycle of the view I have found is didMoveToWindow().
I would have thought that viewDidLoad would be best if it's a one-time thing. Otherwise, viewWillAppear.
EDIT:
If you want to do it in the view, and not it's controller then I would create a custom init for the view along the lines of:
-(id) initWithFrame:(CGRect) frame andAppearanceColor:(UIColor)theColor;
thereby passing the colour into the view at creation time.
I know this is really basic stuff but i need to understand whether my understanding of this is correct.
So what i want to do is this. I want an view with a label on which when double tapped flips and loads another view. On the second view i want a UIPickerView and above i have a button saying back. Both views will be of same size as an UIPickerView which is 320px x 216px.
What i am thinking of to do is create two UIViewclasses named labelView and pickerView. I would then create a viewController which on loadView loads labelView then when user double taps the labelView i get an event in labelView class which is sent to my viewController that then can unload loadView and load the pickerView.
Does this sound as the best way to do this ? Is there a simpler way ? I am also unsure how i route the event from the labelView class to the viewControllerclass.
I dont exactly know the most efficient way to do it(as i am also now to this language),but it is for sure that i have solved ur problem. I made a simple program for that.Three classes involved here in my eg are BaseViewController (which will show two views),LabelView and PickerView (according to ur requirement).
In LabelView.h
#protocol LabelViewDelegate
-(void)didTapTwiceLabelView;
#end
#interface LabelView : UIView {
id <LabelViewDelegate> delegate;
}
#property(nonatomic,retain)id <LabelViewDelegate> delegate;
-(void)didTouch;
#end
In LabelView.m
#synthesize delegate;
-(id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self)
{
UILabel* labl = [[UILabel alloc] initWithFrame:CGRectMake(10, 5, frame.size.width-20,20)];
labl.text = #"Some Text";
[self addSubview:labl];
[labl release]; labl = nil;
self.backgroundColor = [UIColor grayColor];
UITapGestureRecognizer* ges = [[[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(didTouch)] autorelease];
ges.numberOfTapsRequired = 2;
[self addGestureRecognizer:ges];
}
return self;
}
-(void)didTouch
{
[delegate didTapTwiceLabelView];
}
//=============================================================
In Pickerview.h
#protocol PickerViewDelegate
-(void)didTapBackButton;
#end
#interface PickerView : UIView <UIPickerViewDelegate,UIPickerViewDataSource>{
id <PickerViewDelegate> delegate;
}
#property(nonatomic,retain)id <PickerViewDelegate> delegate;
#end
In Pickerview.m
#implementation PickerView
#synthesize delegate;
-(id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self)
{
UIPickerView* picker = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 30, 320, 216)];
picker.delegate = self;
picker.dataSource = self;
[self addSubview:picker];
[picker release]; picker = nil;
self.frame = CGRectMake(frame.origin.x, frame.origin.y, 320, 250);
UIButton* btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[btn setFrame:CGRectMake(10, 1, 50, 27)];
[btn setTitle:#"Back" forState:UIControlStateNormal];
[btn addTarget:self action:#selector(backButton) forControlEvents:UIControlEventTouchUpInside];
[self addSubview:btn];
}
return self;
}
-(void)backButton
{
[delegate didTapBackButton];
}
//====================================================================
in BaseViewController.h
#import "LabelView.h"
#import "PickerView.h"
#interface VarticalLabel : UIViewController<UITextFieldDelegate,PickerViewDelegate,LabelViewDelegate> {
PickerView* myPickerView;
LabelView* myLabelView;
}
#end
In BaseViewController.m
-(void)viewDidLoad
{
[super viewDidLoad];
myPickerView= [[PickerView alloc] initWithFrame:CGRectMake(0, 50, 320, 250)];
[self.view addSubview:myPickerView];
myPickerView.delegate = self;
myLabelView= [[LabelView alloc] initWithFrame:CGRectMake(0, 50, 320, 250)];
[self.view addSubview:myLabelView];
myLabelView.delegate = self;
myPickerView.hidden = YES;
}
#pragma mark PickerViewDelgate
-(void)didTapBackButton
{
myPickerView.hidden = YES;
myLabelView.hidden = NO;
}
#pragma mark LabelViewDelegate
-(void)didTapTwiceLabelView
{
myPickerView.hidden = NO;
myLabelView.hidden = YES;
}
To get events from a button to the view controller, just hook up the button's event, e.g. touch up inside, to a method in the view controller, using interface builder. (Double tapping is probably more complicated though.)
When you say 'flips', do you mean it actually shows an animation of flipping over a view to show a 'reverse' side? Like in the weather app when you hit the 'i' button? I'm assuming this is what you mean.
Perhaps check TheElements sample example on the iPhone Reference Library, it has an example of flip animation.
Btw, it's not strictly necessary to unload the loadView that is being 'hidden' when you flip -- it saves you having to construct it again when you flip back -- but it may be pertinent if you have memory use concerns, and/or the system warns you about memory being low.
Also, what do you mean by "create a UIView"? Do you mean subclass UIView, or just instantiate a UIVIew and add children view objects to it? The latter is the usual strategy. Don't subclass UIView just because you want to add some things to a UIView.
If you've got one screen of information that gives way to another screen of information, you'd normally make them separate view controllers. So in your case you'd have one view controller with the label and upon receiving the input you want, you'd switch to the view controller composed of the UIPickerView and the button.
Supposing you use Interface Builder, you would probably have a top level XIB (which the normal project templates will have provided) that defines the app delegate and contains a reference to the initial view controller in a separate XIB (also supplied). In the separate XIB you'd probably want to add another view controller by reference (so, put it in, give it the class name but indicate that its description is contained in another file) and in that view controller put in the picker view and the button.
The point of loadView, as separate from the normal class init, is to facilitate naming and linking to an instance in one XIB while having the layout defined in another. View controllers are alloced and inited when something that has a reference to them is alloced and inited. But the view is only loaded when it is going to be presented, and may be unloaded and reloaded while the app is running (though not while it is showing). Generally speaking, views will be loaded when needed and unnecessary views will be unloaded upon a low memory warning. That's all automatic, even if you don't put anything in the XIBs and just create a view programmatically within loadView or as a result of viewDidLoad.
I've made that all sound more complicated than your solution, but it's actually simpler because of the amount you can do in Interface Builder, once you're past the curve of learning it. It may actually be worth jumping straight to the Xcode 4 beta, as it shakes things up quite a lot in this area and sites have reported that a gold master was seeded at one point, so is likely to become the official thing very soon.
With respect to catching the double tap, the easiest thing is a UITapGestureRecognizer (see here). You'd do something like:
// create a tap gesture recogniser, tell it to send events to this instance
// of this class, and to send them via the 'handleGesture:' message, which
// we'll implement below...
UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc]
initWithTarget:self action:#selector(handleGesture:)];
// we want double taps
tapGestureRecognizer.numberOfTapsRequired = 2;
// attach the gesture recogniser to the view we want to catch taps on
[labelView addGestureRecognizer:tapGestureRecognizer];
// we have an owning reference to the recogniser but have now given it to
// the label. We don't intend to talk to it again without being prompted,
// so should relinquish ownership
[tapGestureRecognizer release];
/* ... elsewhere ... */
// the method we've nominated to receive gesture events
- (void)handleGesture:(UIGestureRecognizer *)gestureRecognizer
{
// could check 'gestureRecognizer' against tapGestureRecognizer above if
// we set the same message for multiple recognisers
// just make sure we're getting this because the gesture occurred
if(gestureRecognizer.state == UIGestureRecognizerStateRecognized)
{
// do something to present the other view
}
}
Gesture recognisers are available as of iOS 3.2 (which was for iPad only; so iOS 4.0 on iPhone and iPod Touch).