I have a button named start and I want to know in the method that it calls what it's name is and I'm not really sure how to do it. This is the method the button calls.
-(IBAction) startMotion: (id)sender {
UIButton * buttonName = (UIButton *) sender;
NSLog(#"Button Name: %#", buttonName.currentTitle);
}
The NSLog prints
Button Name: (null)
You can set the title of the button through
[b setTitle:#"Start" forState:UIControlStateNormal];
and to get the title (currentTitle is read-only and may be nil):
[b currentTitle];
BTW, if you just want to differentiate multiple buttons, you can just set the tag property (an integer value) of the buttons.
Also, check if you have the button specified as an IBOutlet in your viewController class, and is it connected properly as an outlet in Interface Builder?
I would rather set a certain Tag and compare the tag value rather than reading the title of the button since you have possibility to localize your app where button titles will possibly be different.
I was using the wrong property in Interface Builder.I was using name property of button in Interface Builder instead of the title property from the button settings.
Related
I have made a horizontal scroll view with images and buttons in it using a for loop, what i want to do now is when a button is pressed, open the image it corresponds to full screen. The issue im having is determining which button has been pushed. I am using :
[button addTarget:self action:#selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
then :
-(void)buttonPressed:(UIButton *)sender {}
What can i do to fix this? Thanks
Which button has been pushed
Create a property to store a tag. In the buttonPressed method set the property to sender.tag
Now you can know which was the button who got pressed last.
The sender is the button that the user has tapped, so when you create the buttons you could use the tag property and set it to an index of an array where you hold your images. But this could be a bit unstable if you change the order or amount of images or buttons for example so be prepared to check for that.
one way to do so is to keep references of your button (with a property, an attribute in your class) and test if it is the good one in your buttonPressed method
- (void)buttonPressed:(UIButton *)sender {
if (sender == self.myButton) {
// DO YOUR WORK HERE
}
}
you can also create a method for this and only this one button
by the way it is better to say
- (IBAction)buttonPressed:(UIButton *)sender
you then can set the target of your button in the interface builder interface
set tag for each button in the for loop but.tag=i;
-(void)buttonPressed:(UIButton *)sender {
if (sender.tag==1){
//display image 1
}
else if ....
}
I am developing for iPhone the app I am developing has many buttons and I want all buttons to call the same class but with different parameter
for example I want button1 to call the displayimageclass
and button2 should call the same class displayimageclass so, how to different method call same class and in that same class how to fetch different button from where it is call to particular class.
That is pretty much standard. Just define as many IBAction methods as you need.
In the viewController's .h file:
- (IBAction)actionButton1:(UIButton *)sender;
- (IBAction)actionButton2:(UIButton *)sender;
- (IBAction)actionButton3:(UIButton *)sender;
And in its .m file:
{
//react here to button1 pressed
}
- (IBAction)actionButton1:(UIButton *)sender
{
//react here to button1 pressed
}
- (IBAction)actionButton2:(UIButton *)sender
{
//react here to button2 pressed
}
- (IBAction)actionButton3:(UIButton *)sender
{
//react here to button3 pressed
}
Then associate the action with the Button's events (TouchUpInside would be most appropriate, I guess).
You should add tag property to your buttons.
Suppose your buttons are
button1.tag =1;
button2.tag =2;
button3.tag =3;
When you click any button, NSLog shows related button tag number. i.e You will get your result what you want.
- (IBAction)buttonClicked:(id)sender {
UIButton* button = (UIButton *)sender;
NSLog(#"The number of tag:%d",button.tag);
}
I think it will be helpful to you.
you can implement your action method like this:
- (IBAction)action:(UIButton *)sender
{
//sender will be different for different button
}
Set tag value for buttons and get those buttons like
- (IBAction)action:(UIButton *)sender
{
UIButton *btn = (UIButton*)sender;
}
Are you looking for
1) several buttons performing the same method with the same behavior
2) several buttons performing the same method but having different behavior based on the button characteristics
3) each button performing its own method.
1) You can register several buttons on the same IBAction, they all will call it and perform the same code
2) In the method were all the buttons are registered (cf: 1) it is possible to sort the buttons by subclassing the UIButton class, giving an enum value that represents what the button should perform and then in the called method check the enum value with a switch in order to trigger the wanted behavior
The UIBarButtonItem already has this tag property so you could use them by giving a value to each of your UIBarButtonItem in the Interface Builder and set them to call the following method
- (IBAction) myButtonsMethod:(id)object
if ([object isKindOfClass:[UIBarButtonItem class]])
{
switch ([(UIBarButtonItem *)object tag])
{
case myFirstTagValue
...
}
3) #Hermann Klecker solution is the right one.
I have 5X5 button in a view.
Based on some Condition, i want to interchange them.
How can i know which of them is touched, if move is not possible then a message
alert will be displayed.If the move is possible then current button should replace the
Previous one.
Thanks in Advance...
I suggest you review your question as it is difficult to understand what you really want. But to know which button was touched up inside you can assign unique tags to buttons and then check for the sender's tag. Or another way, declare 25 UIButton IBOutlets (instance variables) and connect them to the buttons in Interface Builder. And then you can check if the [sender isEqual:button1(button2 etc....)].
-(IBAction)buttonTouched:(UIButton*)sender{
if (sender.tag=#"Button1")
..........
}
or
IBOutlet UIButton button1;
..........
-(IBAction)buttonTouched:(UIButton*)sender{
if ([sender isEqual:button1])
.......
}
After clicking the button if you can retreive the title of the button you can use the follwing code(if your button touch down event is connected to this function):-
-(void)btnClicked:(id)sender {
UIButton *rButton = (UIButton *)sender;
NSLog(#" The button's title is %#." rButton.currentTitle);
}
I'm trying to change the properties of various UIButton that I have declared as follows:
UIButton * button1; UIButton *
button2; ....
It's possible to access them in a similar way to this?
[button+i setTitle:#"button"
forState:UIControlStateNormal];
The variable "i" would be an integer to distinguish one from button from another.
you need to use the tag property of UIButton, which is an integer
EDIT to show tag property
UIButton* myButton .... // whichever way your button is init'd
// set the tag
myButton.tag = 2; // or i or whatever way you set it the property is an int
// get the tag
int y = myButton.tag; // set y to the tag value of the button
its that easy
Do you have lots and lots of button?
Okay, the immediate best way I can think of is something I have put into practice when I had something like 30+ buttons on a screen (it was a calendar).
I created an array into which I put the button then accessed them like this (or something like this)
for (UIButton* b in myBigArrayOfButtons) {
[b setTitle:#"button" for State:UIControlStateNormal];
}
How can I make a button that says "Show Picture" and when it's clicked it changes to "Hide Picture". I'm new to objective C, I know how to make a button in interface builder but don't know how to switch the button's text and function. Can someone help me out?
Don't abuse the tag property. It is advise only to be used as a button identifier (for example when you have few buttons in your view you set their tags as 0, 1, 2... so can identify which button is a sender). You could set some global int i variable and change it's value accordingly.
abuse the .tag property of the button. Hook up the touch down action to this function:
-(IBAction)buttonClick:(UIButton*)sender
{
if ( sender.tag )
{
sender.tag = 0;
sender.text = #"Show Picture";
// do actions when "hide" is clicked
} else {
sender.tag = 1;
sender.text = #"Hide Picture";
// do actions when "show" is clicked
}
}
Instead of (ab)using the tag property, you could also simply toggle the button between selected and not selected, like so:
- (IBAction)myButtonAction:(id)sender
{
[sender setSelected:![sender isSelected]];
// or in Objective-C 2.0 if you're so inclined
sender.selected = !sender.selected;
}
In IB, you could then set the text for the normal and the selected state of the button directly in the inspector (or programmatically through the setTitle:forState: method).
The tricky thing with this one is that a UIButton doesn't have an "official" text properly - see the docs here:
http://developer.apple.com/iphone/library/documentation/uikit/reference/UIButton_Class/UIButton/UIButton.html
because it's designed to have multiple, separate sets of texts, displayed according to the button's current state; i.e., whether it's currently enabled or disabled, highlighted, etc. So there's not one, simple property you can set to make this work.
So, you want to declare your button like this, as both an action and an outlet:
from button.h:
// inside the class declaration
BOOL pictureShown ; // initializer not required, defaults to 0 (NO)
UIButton * sampleButton ;
// skip irrelevant lines here
#property (nonatomic, retain) IBOutlet UIButton * sampleButton ;
- (IBAction) doSampleButton ;
Hook both of those up in Interface Builder, and then change the text using the setTitle:forState: method (and in this case, I've specified all the states, so the title stays the same across all of them). For example:
from button.m:
#synthesize sampleButton ;
- (IBAction) doSampleButton {
if (pictureShown == YES) {
// hide the picture, and then...
[sampleButton setTitle: #"Show Picture" forState: (UIControlStateNormal | UIControlStateHighlighted | UIControlStateSelected | UIControlStateDisabled)] ;
pictureShown = NO ;
} else {
// show the picture, and then...
[sampleButton setTitle: #"Hide Picture" forState: (UIControlStateNormal | UIControlStateHighlighted | UIControlStateSelected | UIControlStateDisabled)] ;
pictureShown = YES ;
}
}
You'll also note that I've declared an instance variable, "pictureShown", in the view controller for the view with the button, to track the current "mode" of the button, and that I'm essentially using an if statement inside the button's action to determine which function is carried out according to the current mode of the button, and to toggle the button text accordingly.
(I'm using this to track the current mode of the button rather than, for example, examining the current title of the button directly, or other ways of storing state on the button, because MVC-wise, this sort of state belongs in the controller class.)
(If the function required a lot of code, I'd use messages to self, i.e.:
[self showPicture] ;
[self hidePicture] ;
to avoid having to cram it all inside doSampleButton, but that's purely stylistic, rather than technically required.