Not sure if this is the correct approach but subclassing a UINavigationBar and setting it's translucent to YES doesn't seem to work.
In my implementation file:
- (void)drawRect:(CGRect)rect
{
self.translucent = YES;
}
I was able to override it within a view controller, however, i find myself repeating code and would like to move the implementation in the custom class.
Any thoughts?
Found a solution if anyone needs it. Set self.translucent to YES on init:
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
self.translucent = YES;
}
return self;
}
- (void)drawRect:(CGRect)rect
{
}
Related
I'm create a custom UIView with some sub views.
In the IB - i'v set my subview to be a CreateAlbumView which is a UIView, and created some subviews and outlet those.
When i'm inflating this view in code, and adding it to a super view the follow code is being called:
-(id)initWithCoder:(NSCoder *)aDecoder {
self = [super initWithCoder:aDecoder];
if (self)
[self setViews];
return self;
}
but the subviews are all nil there - making my setViews() function to become useless.
I've changed my code to set the code in the following function, but it doesn't seems right:
-(void)layoutSubviews {
[super layoutSubviews];
[self setViews];
}
Where does the subviews are actually initialized and where can i start using them ?
You should use
- (void)awakeFromNib
The nib-loading infrastructure sends an awakeFromNib message to each object recreated from a nib archive, but only after all the objects in the archive have been loaded and initialized. When an object receives an awakeFromNib message, it is guaranteed to have all its outlet and action connections already established.
I've changed my code to set the code in layoutSubviews, but it
doesn't seems right.
— well, have a method create the views (setViews is a bad name due to cocoa conventions) and layout them and add them in layoutSubviews, than layoutSubviews does exactly what it's name suggests.
-(id)initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder:aDecoder];
if (self)
[self createSubviews];
return self;
}
-(void)layoutSubviews
{
[super layoutSubviews];
for (UIView *v in mySubviews) {
v.frame = CGRectMake(...);
[self addSubview:v];
}
}
I am trying to subclass UILabel. The first try involves that my custom UILabel simply sets the property adjustsFontSizeToFitWidth to YES. The problem is that I am new to iOS programming and unsure about where to put this code. I tried the code below but they are never called.
- (id)initWithFrame:(CGRect)frame
{
NSLog(#"init custom label");
self = [super initWithFrame:frame];
if (self) {
// Initialization code
self.adjustsFontSizeToFitWidth=YES;
}
return self;
}
- (id)init
{
NSLog(#"init custom label");
self = [super init];
if (self) {
// Initialization code here.
self.adjustsFontSizeToFitWidth=YES;
}
return self;
}
I got it to work by using:
lblCustom = [lblCustom init];
But is there someway I can get this call to be called automatically?
When a label is used in interface builder is then the coded use the NSCoder protocol:
- (id)initWithCoder:(NSCoder *)aDecoder
{
NSLog(#"init custom label");
self = [super initWithCoder:aDecoder];
if (self) {
// Initialization code here.
self.adjustsFontSizeToFitWidth=YES;
}
return self;
}
What I do, is create one method to setup my custom UI object and let all the init call this method.
I would personally stay away from initWithCoder: and instead use awakeFromNib instead. Here is why (Apple UIKit Documentation):
The nib-loading infrastructure sends an awakeFromNib message to each
object recreated from a nib archive, but only after all the objects in
the archive have been loaded and initialized. When an object receives
an awakeFromNib message, it is guaranteed to have all its outlet and
action connections already established.
I have a variety of UI subclasses in my program and here is the solution I came up in my BaseLabel class.
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if(self)
{
// We were not loaded from a NIB
[self labelDidLoad:NO];
}
return self;
}
- (void)awakeFromNib
{
[super awakeFromNib];
// We were loaded from a NIB
[self labelDidLoad:YES];
}
- (void)labelDidLoad:(BOOL)loadedFromNib
{
// Do some initialization here...
}
Now all of my subclasses simply override {type}didLoad:(BOOL)loadedFromNib.
For example buttonDidLoad:, textFieldDidLoad:, and tableViewDidLoad: (you get the idea).
Calling only init on an UIView is the same as calling initWithFrame: with a zero-rect. So you should override initWithFrame or initWithCoder if you are using nib-files.
There is an ios library called HGKOptionPane by Jon Arrien. It is a show/hide dropdown panel. While I was implementing it to my demo app, I noticed this UIView frame linked with the UIButton.
I'm sure it has something to do with the code below, I didn't understand the code and I would appreciate if you could explain it. Most importantly, how is the UIButton linked with the UIView or Option Panel it self.
The 2 methods inside HGKOptionPanel.m :
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
- (void)drawRect:(CGRect)rect{
[super drawRect:rect];
isExpanded = YES;
}
Photo:
Option Panel is the UIView with black Background color.
The UIButton is an IBOutlet which is not linked by code.
It is actually all saved in the xib file here:
https://raw.github.com/Hegaka/HGKOptionPanel/master/HGKOptionPanel/HGKOptionPanel/en.lproj/MainWindow.xib
I am new to Core Animation and having trouble implementing a CALayer object with the drawLayer method in a delegate.
I have narrowed the problem down to a very simple test. I have a main viewController named LBViewController that pushes a secondary viewController called Level2ViewController. In the level 2 controller, in viewWillAppear:, I create a CALayer object with it's delegate=self (i.e. the level 2 controller). Whether or not I actually implement the drawLayer:inContext: method I have the same problem -- when I return to the main viewController I get a zombie crash. In the profiler it appears that the object in trouble is the level 2 viewController object -- which is being dealloc'ed after it's popped.
I've tried using a subclassed CALayer object instead of the delegate and it works fine. If I comment out the delegate assignment it also runs fine. I would like to understand why delegation is causing this problem. Any advice is greatly appreciated.
Here's my code ---
Level2ViewController
#implementation Level2ViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewDidAppear:animated];
CALayer *box1 = [[CALayer alloc] init];
box1.delegate = self; // problem disappears if I comment out this assignment
box1.backgroundColor = [UIColor redColor].CGColor;
box1.frame = CGRectMake(10,10,200,300);
[self.view.layer addSublayer:box1];
[box1 setNeedsDisplay];
}
// makes no difference whether or not this method is defined as long
// as box1.delegate == self
- (void)drawLayer:(CALayer *)theLayer inContext:(CGContextRef)theContext
{
CGContextSaveGState(theContext);
CGContextSetStrokeColorWithColor(theContext, [UIColor blackColor].CGColor);
CGContextSetLineWidth(theContext, 3);
CGContextAddRect(theContext, CGRectMake(5, 5, 40, 40));
CGContextStrokePath(theContext);
CGContextRestoreGState(theContext);
}
- (void)viewDidUnload
{
[super viewDidUnload];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
#end
The method in LBViewController (the main controller) that pushes the level 2 view controller
- (IBAction)testAction:(id)sender {
Level2ViewController *controller = [[Level2ViewController alloc]
initWithNibName:#"Level2ViewController" bundle:nil];
controller.title = #"Level2";
// this push statement is where the profiler tells me the messaged zombie has been malloc'ed
[self.navigationController pushViewController:controller animated:YES];
[controller release];
}
You may want to set the layer's delegate to nil before the delegate object is released. So in your Leve2ViewController do this:
-(void)viewWillDisappear:(BOOL)animated
{
if (box1) {
box1.delegate = nil;
}
box1 = nil;
}
Obviously this requires, that box1 is turned into a field (so it is accessible in viewWillDisappear:)
Since you create box1in viewWillAppear: the code above uses viewWillDisappear:. Recently, when I ran into a similar problem, I had a separate delegate object in which I used init and dealloc.
Note: You call [super viewDidAppear:animated]; in viewWillAppear. Looks like a typo or copy/paste glitch :-)
In the ViewController's interface, I have
#property int count;
and in the implementation, I have
#synthesize count;
-(id) init {
self = [super init];
if (self) {
self.count = 100;
}
return self;
}
-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"%i", self.count++);
}
but for some reason, the first time self.count got printed, it is 0 but not 100?
One of various -init methods will be called on your UIViewController, depending on whether it came out of a .xib, storyboard, or is alloc'd manually somewhere else in your code.
A better place to put this kind of initialization is in -viewDidLoad, something like this
- (void)viewDidLoad {
[super viewDidLoad];
self.count = 100;
}
Put a NSLog or debugging breakpoint in your init method and I suspect you'll find it isn't called. If you look at UIViewController, you'll see other initialization methods (e.g. if you're using a NIB, it would invoke initWithNibName:bundle:). If it's via a storyboard, it can differ. See the discussion of initialization in Apple's View Controller Programming Guide for iOS.
A better place for general view controller configuration is viewDidLoad.
Change it to:
- (id)initWithCoder:(NSCoder *)aDecoder{
self = [super initWithCoder:aDecoder];
if (self) {
self.count = 100;
}
return self;
}
The view is actually getting created by the XIB, which is 'decoding' it or unboxing it. When this happens, the XIB calls initWithCoder: