I need to add two additional properties (NSString * and NSMutableArray *) along with three extra methods to UIButton. I also want to reference the new objects using a supertype if that is possible. I do not necessarily want to subclass (as I read that it is tricky and not recommended), but I am quite new to Objective-C and iOS development and don't know what else to do.
I tried to subclass UIButton with my subclass implementing a formal protocol in the following way:
#interface Button : UIButton <MyProtocol> ...
However, I found out this doesn't work like I thought it would, as buttonWithType: returns an object from a subclass. What else can I do to achieve the desired result?
-- EDIT:
Ok, my current code is like this:
#interface Button : UIButton <SteapeObject> {
ActionQueue * actions;
Meta meta;
}
#property (nonatomic, retain) ActionQueue * actions;
#property (nonatomic) Meta meta;
- (id) initWithFrame:(CGRect)frame;
...
And the implementation:
- (id) initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
NSLog (#"finally");
}
return self;
}
An still doesn't work. It seems that when I invoke:
Button * button = [Button buttonWithType: UIButtonTypeRoundedRect];
NSLog (#"%#", [button description]);
I should get two 'finally' strings and two descriptions in the log. However, I only get the two description strings:
[Session started at 2011-02-24 09:47:14 +0100.]
2011-02-24 09:47:15.431 IphoneClient3[702:207] <UIRoundedRectButton: 0x5f47690; frame = (0 0; 0 0); opaque = NO; layer = <CALayer: 0x5f47240>>
2011-02-24 09:47:15.461 IphoneClient3[702:207] <UIRoundedRectButton: 0x6a0f000; frame = (0 0; 0 0); opaque = NO; layer = <CALayer: 0x6a344b0>>
And you can see that the type is still UIRoundedRectButton, but the buttons do not respond to my added methods. Actually, since my overriden initWithFrame doesn't get called, that is to be expected. Perhaps I should default to implementing a custom control...
As far as I know, the doc does not say subclassing of UIButton is not recommended.
I have done it multiple times to add custom properties — without problems.
The only thing to do is to create the button using:
[Button buttonWithType:UIButtonTypeCustom]; // won't work for other button types though
Use a Category.
#interface UIButton (MyButtonCategory)
- (void) myMethod;
#end
#implementation UIButton (MyButtonCategory)
- (void) myMethod
{
NSLog(#"Called myMethod!");
}
#end
[EDIT]
Alternatively, if I finally understand you, you can do this.
#interface MyButton : UIButton
- (id) initWithFrame:(CGRect)rect;
#end
#implementation MyButton
- (id) initWithFrame:(CGRect)rect
{
if ((self = [super initWithFrame:rect])){
// Do your init in here
}
return self;
}
#end
Then calling
MyButton *btn = [MyButton buttonWithType:UIButtonTypeRoundedRect];
Should get you what you want. buttonWithType should call initWithFrame on your subclass.
I found that it is not possible to accomplish that task with the current implementation of the SDK.
Categories might help. Implement like this:
//In the UIButtonMyExtras.h file
#interface UIButton(MyExtras)
//extras
#end
//In the UIButtonMyExtras.m file
#implementation UIButton(MyExtras)
//extra implementation
#end
This adds these extras to every UIButton in your project.
Related
I want to make an Advertising banner in my app. A bit like iAd's.
I was going to make it by having a UIImage on the view then assigning the banner image. I would then add a touch gesture so the user could click it and go to another view in my app. I Know That I can do this on one view quite easily but I want this to be on most views in the app. Whats the best way for adding the banner to more than one view with out writing the same code more that once?
The below design shows the sort of banner im after.
Thanks
#import <UIKit/UIKit.h>
#class custom;
#protocol adDelegate
- (void)viewAd:(NSString *)adRate;
#end
#interface custom : UIView
#property (strong, nonatomic) UIImage *viewImage;
#property (assign) id <adDelegate> delegate;
#end
// Main class
#import "custom.h"
#implementation custom
#synthesize viewImage;
#synthesize delegate;
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
UIImageView *imageView = [[UIImageView alloc] initWithFrame:frame];
imageView.image = viewImage;
[self addSubview:imageView];
}
return self;
}
- (id)initWithCoder:(NSCoder *)aDecoder
{
if ((self = [super initWithCoder:aDecoder]))
{
}
return self;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[self.delegate viewAd:#"view"];
}
You can Create a UIView Class and call it BannerView for instance.
// in the bannerView.h
#import <UIKit/UIKit.h>
#interface BannerView : UIView{
UIImageView* bannerImage;
}
#property(nonatomic,retain) UIImageView* bannerImage;
#end
//in the bannerView.m
#import "BannerView.h"
#implementation BannerView
#synthesize bannerImage;
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
// Drawing code
bannerImage=[[UIImageView alloc]initWithImage:[UIImage imageNamed:#"banner-image.png"]];
bannerImage.frame=CGRectMake(0, 0, 320, 100);
[self addSubview:bannerImage];
// add a uibutton on top of the uiimageview and assign an action for it
// better than creating an action recogniser
UIButton* actionButton=[UIButton buttonWithType:UIButtonTypeCustom];
actionButton.frame=CGRectMake(0, 0, 320, 100);
[actionButton addTarget:self action:#selector(yourAction) forControlEvents:UIControlEventTouchUpInside];
[self addSubview:actionButton];
}
-(void) yourAction{
// do what ever here like going to an other uiviewController as you mentionned
}
#end
Now you can call this view from any View Controller this way
BannerView* banner=[[BannerView alloc] initWithFrame:CGRectMake(0, 300, 320, 100)];
[self.view addSubview:banner];
Try creating a parent class from UIView where you do all the display and handling of the banner using your UIImageView and gesture recognizers. Then whichever views need this functionality, derive them from this parent class, and override default handling in method so that you can customize the behavior in your child class.
A few suggestions:
First, why not just use a UIButton instead of a UIImage with a Gesture? All you're really doing is replicating button functionality after all...
Second, I'd probably tackle the overall problem by creating a class that includes the UIButton, like so:
#interface YourSuperViewController : UIViewController
#property (nonatomic, strong) IBOutlet UIButton *adButton;
- (IBAction)adTouched:(id)sender;
#end
In the viewDidLoad for this class, create the button, and add it to the view, and add your ad-specific logic to the adTouched action.
Then create the rest of the views in your app as an instance of YourSuperViewController. Like so:
#interface SomeOtherViewController : YourSuperViewController
Now the SomeOtherViewController will auto-magically have the ad button and respond to a touch on it properly. Done!
What everyone else has said is the best way. If you need custom functionality, subclassing is probably the way to go.
I just wanted to add one pedantic thing. Its important to remember that a UIImage is not a view. There has never been a UIImage on the screen, ever. A UIImage is a model object. It is just a collection of data. A UIImageView is a view object and as such, a UIImageView can display itself on the screen.
This might seem overly pedantic and nitpicky, but its important to have these things sorted out in our heads in order to effectively use MVC (model, view, controller)
having a little issue in an ARC environment. Creating an NSObject that adds a view to a parent view - it's basically a 'popup class' that can handle some text and display it.
In a view controller it's instantiated..
CBHintPopup *popup = [[CBHintPopup alloc]init];
[popup showPopupWithText:#"test text" inView:self.view];
And the actual class files..
CBHintPopup.h
#interface CBHintPopup : NSObject {
}
-(void)showPopupWithText:(NSString *)text inView:(UIView *)view;
-(IBAction)closePopup;
#property (nonatomic, strong) UIView *popupView;
#property (nonatomic, strong) UIImageView *blackImageView;
#property (nonatomic, strong) UIButton *closeButton;
#end
CBHintPopup.m
#implementation CBHintPopup
#synthesize popupView,blackImageView, closeButton;
-(void)showPopupWithText:(NSString *)text inView:(UIView *)view {
//CREATE CONTAINER VIEW
self.popupView = [[UIView alloc]initWithFrame:CGRectMake((view.frame.size.width/2)-(225/2),-146,225,146)];
self.popupView.alpha = 0;
self.popupView.backgroundColor = [UIColor clearColor];
//CREATE AND ADD BACKGROUND
UIImageView *popupBackground = [[UIImageView alloc]initWithFrame:CGRectMake(0,0,225,146)];
popupBackground.image = [UIImage imageNamed:#"hintbackground.png"];
[self.popupView addSubview:popupBackground];
//CREATE AND ADD BUTTON
self.closeButton = [UIButton buttonWithType:UIButtonTypeCustom];
[self.closeButton addTarget:self action:#selector(closePopup) forControlEvents:UIControlEventTouchUpInside];
[self.popupView addSubview:self.closeButton];
//CREATE AND ADD LABEL
UILabel *popupTextLabel = [[UILabel alloc]initWithFrame:CGRectMake(22,25,176,93)];
popupTextLabel.text = text;
[self.popupView addSubview:popupTextLabel];
[view addSubview:self.popupView];
}
-(void)closePopup {
NSLog(#"HI");
}
Recieving the following once closePopup is called via pressing the button ('HI' is not printed)..
-[CBHintPopup performSelector:withObject:withObject:]: message sent to deallocated instance 0x246b2fe0
I've tried retaining the button in non-ARC and a load of other methods but simply having no luck. Probably something real simple but i can't nail it. I've removed all the setting up of the labels and images etc to save some space, so ignore alpha's etc.
Any help will be much appreciated, thanks for your time.
Have you implemented the constructor for CBHintPopup,since you have called the constructor
[[CBHintPopup alloc]init];
you have to implement the constructor method like this
in .m file of CBHintPopup
-(id)init{
if(self == [super init]){
// do some initialization here
}
return self;
}
I tried your code and found the crash you mentioned. I found a solution for fixing the crash.
I declared the CBHintPopup *popup; in the viewController's interface. And changed this line
CBHintPopup *popup = [[CBHintPopup alloc]init];
to
popup = [[CBHintPopup alloc]init];
Everything worked fine for me. But I couldn't find the reason behind this. Hope this will help you.
Found a fix for it - instead of CBHintPopup being an NSObject, i simply made it a sub-class of UIView and added self to the parent view (instead of self.popupView). I wouldn't really call this a 'fix' though - more of an alternative method. Surely an NSObject can add a UIView (with a UIBUtton) to a parent view with no problems? Is this a bug?
Make sure you are retaining the object for class CBHintPopup.
I think the crash is coming because object of CBHintPopup deallocates. And hence the action method is not found.
I have an IBOutletCollection of UIButtons:
#property (nonatomic, retain) IBOutletCollection(UIButton) NSMutableArray *Buttons;
with an ibaction i would to change the highlighted state permanently after the touch down event.
This Problem is very similar to this:
IBOutletCollection of UIButtons - changing selected state of buttons
... but with the for-loop the buttons doesnt change.
i also tried the perfomselector method from here: Keep iPhone UIButton Highlighted
but it doesnt work.
now my code:
-(IBAction)toggleButtons:(id)sender
{
NSUInteger Index = [button tag];
[[Buttons objectAtIndex:Index] setHighlighted:YES];
}
if i change line four to this:
[[Buttons objectAtIndex:3] setHighlighted:YES];
it works for the fourth element in my collection... But not with the index variable....
regards, phil
Update
SelectionViewController.h
#import <UIKit/UIKit.h>
#interface SelectionViewController : UIViewController
#property (nonatomic, retain) IBOutletCollection(UIButton) NSMutableArray *Buttons;
- (IBAction)toggleButtons:(id)sender;
#end
SelectionViewController.m
#import "SelectionViewController.h"
#interface SelectionViewController ()
#end
#implementation SelectionViewController
#synthesize Buttons;
-(IBAction)toggleButtons:(id)sender
{
UIButton *button = sender;
NSUInteger Index = [button tag];
[self performSelector:#selector(doHighlight:) withObject:sender afterDelay:0];
[[Buttons objectAtIndex:Index] setHighlighted:YES];
}
- (void)doHighlight:(UIButton *)b {
[b setHighlighted:YES];
}
Okey Update 2:
Now i had declared my Buttons as normal IBOutlet and this is not working:
-(IBAction)toggleButtons:(id)sender
{
UIButton *button = sender;
[button setHighlighted:YES];
}
But if change it to this:
-(IBAction)toggleButtons:(id)sender
{
[myOutletButton setHighlighted:YES]; //Normal Outlet
}
it works....
But why is not possible with the sender?
regards!
Update 3
This works also:
for(id button in self.view.subviews)
{
[button setHighlighted:YES];
}
Ok if change the delay time in the selector to 1, the state will be highlighted. I am using "touch down" event... i think after i touched up the button gets its old state. Which event is the right?
Given that your example works with a specific integer, the problem is probably that the tag property is not set properly for each of your buttons. If the buttons are created in interface builder, each of them will have a default tag value of 0. To check this, click on the button and then, in the Attributes Inspector, scroll down to View and see what value is entered in the tag field
I am new to objective C and I have a c++ background. I want to display a value in the label on the screen. I am calling the label value from the MainView.m. However, the label becomes blank after I click a button instead of printing a value. What is the problem? Here is the code.
MainView.h
#interface MainView : UIView {
int a;
}
-(int) vr;
#end
MainView.m
-(int) vr
{
return 100;
}
#end
MainViewController.h
#interface MainViewController : UIViewController {
IBOutlet UILabel *myLabel;
NSMutableString *displayString;
MainView *view1;
}
#property (nonatomic, retain) UILabel *myLabel;
#property (nonatomic, retain) NSMutableString *displayString;
(IBAction)showInfo;
(IBAction) pressButton:(id) sender;
#end
MainViewController.m
#synthesize myLabel, displayString;
-(IBAction) pressButton:(id) sender{
[displayString appendFormat:#"%i", view1.vr];
myLabel.text = displayString;}
- (void)viewDidLoad {
view1 = [[MainView alloc] init];
[super viewDidLoad];}
- (void)dealloc {
[view1 dealloc];
[super dealloc];}
I have not mentioned code that had been auto generated. This is enough to get the whole picture. I tried a lot to debug this thing. I believe that IBAction carries out direct command such that
myLabel.text = #"string";
but it does not invoke any method or class. Any subtle ideas? Thanks.
Few issues:
1
In MainView.h you declare -(id) vr;
And in MainView.m it returns int.
2
Maybe pressButton is not connected to the right event in Interface Builder (it is usually touch up inside).
Try to write to log in this method.
3
Maybe myLabel is not connected to the label in the Interface Builder.
Try to set tome hard-coded string to label's text property.
4
Do you initiate view1 in some place?
Can you post this piece of code too?
5
You can use [displayString appendFormat:#"%i", view1.vr];...
EDIT (due to changes in question):
6
The line [super viewDidLoad]; should be the first line inside viewDidLoad.
7
[view1 dealloc]; - never call dealloc directly on objects. Call release instead. The only place, where you can and should use dealloc is the line [super dealloc]; inside dealloc method.
8
When you format your question/answer in Stack Overflow, remember that each code line should start with at least 4 spaces (or tab). Try reformatting you question by adding 4 spaces in the beginning of each code line.
9
I think that displayString is not initiated. Add the next line in the viewDidLoad: displayString = [NSMutableString new];
I'm going to write my own custom control that is very different from UIButton. It's so much different that I decided to write it from scratch. So all I subclass is UIControl.
When my control is touched up inside, then I want to fire a message in means of target-action. The user of that class may instantiate it and then add some targets and actions for this event.
i.e. imagine I would call internally a method -fireTargetsForTouchUpEvent. How could I maintain this target-action-mechanism in my class? Do I have to add all targets and actions to my own array and then just call selectors (the actions) on the target objects in a for-loop? Or is there a more intelligent way to do it?
I imagine to provide some methods for adding targets and actions for some events like that touch up event (I raise that manually by calling a internal method when that happens). Any idea?
I just want to clarify what #Felixyz said because it wasn't clear to me at first.
If you are subclassing UIControl, even if you are going to have a custom event, you don't have to keep track of your own targets/actions. The functionality is already there, all you have to do is call the code below in your subclass to trigger the event:
[self sendActionsForControlEvents:UIControlEventValueChanged];
Then in the view or view controller that instantiates your custom UIControl, just do
[customControl addTarget:self action:#selector(whatever) forControlEvents:UIControlEventValueChanged];
For custom event, just define your own enum (for example, UIControlEventValueChanged is equal to 1 << 12). Just make sure it is within the permitted range defined by UIControlEventApplicationReserved
You have the right idea. Here is how I would do it:
#interface TargetActionPair : NSObject
{
id target;
SEL action;
}
#property (assign) id target;
#property (assign) SEL action;
+ (TargetActionPair *)pairWithTarget:(id)aTarget andAction:(SEL)selector;
- (void)fire;
#end
#implementation TargetActionPair
#synthesize target;
#synthesize action;
+ (TargetActionPair *)pairWithTarget:(id)aTarget andAction:(SEL)anAction
{
TargetActionPair * newSelf = [[self alloc] init];
[newSelf setTarget:aTarget];
[newSelf setAction:anAction];
return [newSelf autorelease];
}
- (void)fire
{
[target performSelector:action];
}
#end
With that class in place, storing your target/action pairs is pretty straightforward:
MyCustomControl.h:
#import "TargetActionPair.h"
#interface MyCustomControl : UIControl
{
NSMutableArray * touchUpEventHandlers;
}
- (id)init;
- (void)dealloc;
- (void)addHandlerForTouchUp:(TargetActionPair *)handler;
#end
MyCustomControl.m:
#import "TargetActionPair.h"
#implementation MyCustomControl
- (id)init
{
if ((self = [super init]) == nil) { return nil; }
touchUpEventHandlers = [[NSMutableArray alloc] initWithCapacity:0];
return self;
}
- (void)dealloc
{
[touchUpEventHandlers release];
}
- (void)addHandlerForTouchUp:(TargetActionPair *)handler
{
[touchUpEventHandlers addObject:handler];
}
- (void) fireTargetsForTouchUpEvent
{
[touchUpEventHandlers makeObjectsPerformSelector:#selector(fire)];
}
#end
After that, setting up the control would be done as follows:
[instanceOfMyControl addHandlerForTouchUp:
[TargetActionPair pairWithTarget:someController
andAction:#selector(touchUpEvent)];
Since you're planning to subclass UIControl, you can just use
- (void)addTarget:(id)target action:(SEL)action forControlEvents:(UIControlEvents)controlEvents;
Using this, any class can register itself as a target for any events it wants to on your custom controller.