I need several UIButtons to all connect to the same IBAction so the buttons can all do the same thing without having to copy and paste the code. Please tell me if there is a way to do this! It might be right under my nose, but I can't find it. Thanks!
Simply add the same target and selector to each button:
[button1 addTarget:self
action:#selector(buttonClicked:)
forControlEvents:UIControlEventTouchUpInside];
[button2 addTarget:self
action:#selector(buttonClicked:)
forControlEvents:UIControlEventTouchUpInside];
// etc.
For this You need to use set IBOutlet for Each Button or Set tag for each button if you are using Outlet then used this code .h
#interface RootViewController_Phone : UIViewController
{
IBOutlet UIButton *btn1;
IBOutlet UIButton *btn2;
}
- (IBAction)buttonPressed:(id)sender;
-(void)CallButtonsMethod;
#end
Now in .m file
- (IBAction)buttonPressed:(id)sender{
if([sender isEqual:btn1])
{
[self CallButtonsMethod];
}
if([sender isEqual:btn2])
{
[self CallButtonsMethod];
}
}
-(void)CallButtonsMethod
{
//your Code
}
Use IBOutletCollections.
Here is tutorial for that:
http://useyourloaf.com/blog/2011/03/28/interface-builder-outlet-collections.html
I've found that I'm usually not able to hook up multiple buttons (or even a single button, for that matter) in IB to an already existing IBAction in code, by Ctrl-dragging from the button to the IBAction in the m file. Xcode tries to create a new action in the dragged-to file, but won't connect to an existing action. [This is true for Xcode 4.6.1 and several previous (maybe all) versions.]
The approach in the accepted answer in the following link works if the IBAction is in the view controller which is the "File Owner" for the view containing the button:
Connect object in .xib to existing IBAction
However if you want your IBAction to be in the view's own class, rather than the view controller's class, then the following approach works:
Drag only one button onto the canvas in IB first. Control-drag from
the button to the view's .m file.
Drop the dragged line in any vacant space in the implementation section of the code.
Define a new IBAction in the little popup dialogue box. So now you have one
button hooked up to an IBAction.
Now instead of dragging more buttons from the object library, hold
down the Option key and drag out a new button from the original one.
This new button will come hooked up to the same IBActions as the
original one. (If you need to create lots and lots of buttons and
this seems tedious, you can select a bunch of already created ones simultaneously and
Option-drag to create as many more in a single go.)
Related
I have a Button1 which has IBAction. Also I set target and action for my button
- (void)setTarget:(id)target action:(SEL)action {
[self.Button1 addTarget:target action:action
forControlEvents:UIControlEventTouchUpInside];
}
So when I pressed the button firstly IBAction did what he should, and than action that I set to button. Is that order always be like that ?
If you are loading you view or view controller from a nib file then yes the pattern will always be the IBAction even first followed by the target you have added to the button.
In effect adding an IBAction in Interface Builder is really just telling IB to call ["UIControl" addTarget:"id" forControlEvents:"UIControlEvent"], and you can add multiple targets to a UIButton.
In effect your code will load everything from the NIB file first (if you are using initWithNib:named:), so this will call the addTarget function on the button first with the action you have specified in Interface Builder, then at some later point the setTarget function you have above will get called, which will add another target action to the button. A UIControls targets are stored in an array which is accessed in order and will trigger if control events are met in the order they were created in.
If you look in the header file for UIControl (the super class for UIButton) you will see that NSMutableArray* _targetActions is an array. So the order is guaranteed to fire like this unless you reorder this array after it is created at some point.
In my project I have a button that calls a function via a IBOutlet, I need to know how can I put in the function code to make disable the button, as I identify the button (using tags?)
And what to write?
I think you're slightly confused. Your button is connected to a method via an IBAction. You'll need to create a #property for your button and connect it to IB via an IBOutlet.
Alternatively you could utilize the sender argument from the IBAction. Something like this perhaps...
- (IBAction)buttonPressed:(id)sender
{
UIButton *buttonThatWasPressed = (UIButton *)sender;
buttonThatWasPressed.enabled = NO;
}
Very simply.
self.yourButton.enabled = NO;
For that make code like this
button.enabled=NO;
& if you want to enable it agaian code like this
button.enabled=YES;
I need to generate a custom button through code, this is how i am currently doing it.
-(void) initialiseButtons
{
int ypos = playerImage.frame.origin.y + playerImage.frame.size.height + 8;
for(int i=0; i<totalButtons; i++)
{
UIButton *newButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[newButton setFrame:CGRectMake(20, ypos, 220, 30)];
newButton.tag = 10 + i;
[newButton addTarget:self action:#selector(statTapped:) forControlEvents:UIControlEventTouchUpInside];
[self.frontView addSubview:newButton];
ypos += 30 + 7;
}
}
This creates the blank buttons perfectly through code, gives them a tag and assigns an callback function on touchUpInside.
The custom button needs to be able to handle showing an image when pressed down.
It needs to be able to draw 2 pieces of Text. 1 aligned to the left hand side of the button and 1 aligned to the righthand side of the button.
My boss suggested instead of buttons I use a View. I dont understand how this will work. When i start thinking about it, i think it would require having a viewcontroller dedicated to the buttons. And some draw method? It sounds complicated and I am not grasping how it can be done.
Is there a simpler method by making a custom class overriding UIButton? I made a simple test class earlier but nothing was drawn in the buttons locations when I used them in place of the Normal UIButton class. I expected i would see the buttonUp.png drawn.
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
#interface CardButton : UIButton {
}
#end
#import "CardButton.h"
#import <UIKit/UIKit.h>
#implementation CardButton
- (id)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:frame])
{
[self setImage:[UIImage imageNamed:#"buttonUp.png"] forStates:UIControlStateNormal];
self.adjustsImageWhenHighlighted = YES;
}
return self;
}
#end
Anybody able to give me some pointers on this? I'm pretty blocked at the moment. Have been reading some various other threads related to buttons but nothing that made it clear in my head how to tackle the problem
Personally, I would subclass UIButton. Despite all the talk that you can't subclass UIButton, Apple even talks about subclassing UIButton in the UIButton documentation.
In the subclass I would create a UIView with the two labels (or images or whatever) and add them as subviews to the button (be sure to set interactive for the text and view as FALSE).
What is awesome about this is that it leverages the UIButton code and keeps you from reinventing the wheel.
You should not (I'd almost say you can't) subclass UIButton, as it turns out to be a class cluster, and it would be impractical (read: impossible) to derive from that.
So your two options are:
1) Use standard UIButton of custom type, add the elements you want to show (i.e. UILabel) and hook up actions for touch down and touch up and react accordingly (change the views, trigger actions etc.)
2) Use a custom UIView, implement drawRect: to draw how you like it or use custom views as subviews as in 1). Then use the touchesBegan:, touchesEnded: etc. messages to react accordingly (or UIGestureRecognizer if you can live with 3.2+ compatibility).
You might build a factory to build those buttons if they all are very similar, so that your code becomes clean and non-repetive.
Edit as per iOS 6:
Apple now mentions subclassing in the UIButton docs, so while still not very well defined, it seems quite safe now to do so.
An easy way to do this, is to override a UIView. In the view you add a UIButton as Subview. This way you have a reusable class without the need to re-implement button behaviour.
You can style your button the way you want in the initWithFrame method of your UIView derived class. If you use this class as target for your button events, you can implement special behaviour easily, like showing the image.
For the two pieces of text, you create two labels and add them as subviews to the button.
I have a small iPhone app which I've created a button with some functionality in. My question is, how can I call this button without actually pressing it?
Any help would be appreciated!
Thanks
If you want to activate whatever target a button is wired to, you can call:
[button sendActionsForControlEvents:UIControlEventTouchUpInside];
(TouchUpInside is the event you'd normally wire a button action to). This way if other targets are added or changed for any button (say for debugging) you don't have to alter your code.
This method is on UIControl which UIButton inherits from, which is why you might have overlooked it at first glance...
Have your button event call a function. You can also manually call the function yourself.
Example:
- (void) btnFunction {
NSLog (#"test");
}
...
UIButton *btn1 = [UIButton buttonWithType:UIButtonRoundedRect];
// other code to set up button goes here
[btn1 addTarget:self action:#selector(btnFunction) forControlEvents:UIControlEventTouchUpInside];
You can also call the function yourself:
[self btnFunction];
Your button shouldn't have functionality, it should just send a message to its target (or call a method, or call a function...).
You're free to send that message to that target yourself.
e.g. Your button's target outlet is connected to an IBAction on your controller. That IBAction is just a method of the form:
- (void) doSomething:(id)sender
In your own code do:
[controller doSomething:self];
It's exactly the same as having your button do it.
This is a very simple iPhone / Cocoa question. I have a button that transitions between two views. I set most of this up using interface builder. When I click the button and the second view is displayed, how do I programmatically change the text of the button (to say 'back', for instance)?
In your class declaration, declare a button object, and make sure it is specified as an IBOutlet:
IBOutlet UIButton* myButton;
Once you save this change, if you go back to Interface Builder, you should see this outlet when you right click on your File's Owner (assuming you have specified the File's Owner properly). Associate this outlet with the onscreen UIButton by right-click dragging.
Now the on screen object is associated with your in-code name.
Whereever you want to change the text on the UIButton, just say:
[myButton setTitle:#"Back - or whatever else you want it to say"
forState: UIControlStateNormal ];
// you can set different title text for each state
// of the button (selected, active, or normal)
Alternately, you can assign a unique tag to the control and use -[UIView viewWithTag:] to get a UIView pointer to the control. In most cases, outlets are the preferred mechanism, but tags are useful in things like table cells.
You'll need to set up an outlet for IB:
#interface MyViewController : UIViewController {
IBOutlet UIButton *myButton;
}
Save, bring up IB, set the file's owner to MyViewController, then create referencing outlets from both your UIView and UIButton to the appropriate points in the file's owner in the Connections Inspector.
Then in the implementation, you could do:
[myButton setTitle:#"Back" forState:UIControlStateNormal];
If you get lost with the connections, I'd recommend having a look at the lecture notes and video lectures at http://www.stanford.edu/class/cs193p/cgi-bin/index.php , which go into some detail about iPhone basics.
Hope that helps.
Most of the posts so far have focused on creating the button, and are very correct. The following answers the rest of the question:
When I click the button and the second view is displayed, how do I programmatically change the text of the button (to say 'back', for instance)?
The easiest way, if I understand your circumstance correctly, is to use the plug-n-play UINavigationBarController. First you want to push your second view controller onto the view stack:
// In firstViewController.m
self.navigationController = [[UIViewController alloc]initWithNibName:#"secondView" bundle:nil];
[self pushViewController:secondViewController animated:TRUE];
When your second view controller is shown, you should automatically get a back button on the left side of the nav-bar. If there is a need to change the text of that back button, you can simply refer to it like so:
// In secondViewController.m
-(void)ViewWillAppear
{
[self.navigationItem.backBarButtonItem setText:#"GoBack"];
}
There are also the left and rightBarButtonItem(s) which are handy for more complex navigation. Here is a less plug-n-play scenario:
// In secondViewController.h
-(IBAction)goBack; (this should appear as an action in your associated nib file)
// In secondViewController.m
-(void)viewDidLoad
{
self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:#"GoBack" style:UIBarButtonItemStylePlain target:self action:#selector(goBack)];
}
-(IBAction)goBack
{
// logic to be done before going back
[self popViewControllerAnimated:secondViewController animated:TRUE];
}
You need to define and connect an "outlet". Take a look at the documentation, making note of the section on "Connections and Bindings".