I have a button in my iphone app, when I click the button it calls a linked method, that I have done as:
[myButton addTarget:self action:#selector(buttonTapped:) forControlEvents:UIControlEventTouchUpInside];
all working well, but i want if user tap the button for say 5 second continuously then he will be shown a message that will be there and gone away after some time and button does not get clicked, how can I do that, please help me.
Many Thanks in advance.
Regards
iPhone Developer11
Youcould use UIControlEventTouchDown and make sure it is touched down in the right view and if it is start a timer. If there are no UIControlEventTouchUpInside for 5 seconds you do whatever you need to do.
You should check docs for UILongPressGestureRecognizer. I think it fits your requirements.
Related
I have a button, and I'd like to call a function when the user pushes it then call a different function when he releases it.
Right now I'm using this to create the button:
[ScanButton addTarget:self action:#selector(scanButtonPressed)
forControlEvents:UIControlEventTouchUpInside];
to call scanButtonPressed. As of now scanButtonPressed is only called upon release. How do I change this?
Thanks
How about by trying a control event other than UIControlEventTouchUpInside?
Try - UIControlEventTouchDown .
This contains all of the different events you can pass to a button
UIControl Class Reference. Try looking at these; both UIControlEventTouchUpInside and UIControlEventTouchDown will work.
I need to implement such kind of functionality in my slider such that the submit button should not appear till the user pull up his fingers from slider.
Is there any kind of function which can duplicate this.
Thanks,
The UISlider has a continuous property. Set this to NO, and you will only receive valueChanged events when the user is done choosing his value. Then add a target for the valueChanged event, and there you can set the button to be enabled.
If you can't set continuous to NO for some reason, observe the UIControlEventTouchUpOutside and UIControlEventTouchUpInside events:
[yourSlider addTarget:self
action:#selector(showSubmit:)
forControlEvents:UIControlEventTouchUpInside|UIControlEventTouchUpOutside];
And
- (void)showSubmit:(UISlider *) {
// code to show your button here
}
Is there a similar method in xcode to the AS3 "AddEventListener" code?
I want to be able to watch for a certain thing to happen, but not use up too much memory.
Basically I have 8 buttons. Obviously I can't just go through a for loop to see if a touch is on them, I need an event or a trigger or something.
(The reason I don't just use normal buttons is that I need to be able to slide onto them.)
Any ideas?
I assume you are implying you are using UIView and not UIButton. What you are looking for is a UIGestureRecognizer, which you would attach to the view. Review the SimpleGestureRecognizers sample project for examples of how to accomplish this.
[yourButton addTarget:self action:#selector(clickHandler:) forControlEvents:UIControlEventTouchUpInside];
-(void)clickHandler:(id)sender{
//your actions
}
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.
I am trying to add an info button to my app to provide custom help.
Instead of adding the button to the nib and linking the event (touchUpInside) to the controller, I decided to add the button programmatically. The button shows up. When I add the target event handler to be executed when the button is touched, it does not work. That my method(doHelp) is not being called on touching the button.
When I debugged it, the event is not registered with the button! Although the code does not throw any exceptions.
Here is the code snippet FROM the view:
// Create a Button to get Help
UIButton *helpButton = [UIButton buttonWithType:UIButtonTypeInfoDark ] ;
buttonRect = helpButton.frame;
// CALCulate the bottom right corner
buttonRect.origin.x = rect.size.width - buttonRect.size.width - 8;
buttonRect.origin.y = rect.size.height - buttonRect.size.height - 8;
[helpButton setFrame:buttonRect];
[helpButton addTarget:self action:#selector(doHelp:) forControlEvents:UIControlEventTouchUpInside];
[helpButton setEnabled:TRUE];
[self addSubview:helpButton];
........
// Another METHOD ELSEWHERE in the VIEW object
-(void)doHelp:(id)Sender
{
[self setHelpNeeded:TRUE];
[self setNeedsDisplay];
}
What am I doing wrong please?
I have looked at the SDK help and samples and am really flummoxed!
Am hoping another pair of eyes will help! :-)
This code snippet is in the View Object in case you need to know.
I just added the doHelp to help the first 2 responders... thanks.
**UPDATE 6/4/09 ** -
I have been trying all night and nothing worked. I think there is something wrong in the way I have set up the method selector as my method never gets called. Everything else looks fine. Even using a NIB file does not work. I have tagged the button, retrieved it and added the method selector but to no avail. There is something fundamental which I am doing wrong... Argh!!!
Any ideas, anyone?
Resolved it finally!!! and learnt something in return. Did cost me a few days to figure this out.
The reason my UIButton object was not working was because I found that in case of a UIIMageView object:
"initWithImage: This method adjusts the frame of the receiver to match the size of the specified image. It also disables user interactions for the image view by default."
AND my UIButton had been assigned as a subview of a UIImageView control !!!
There was no errors / warnings. It just gets disabled quietly.
Solution: Created a container UIView object which now contains the UIImageView AND the button so that the button appears as overlayed on the Image but it is actually a sibling of the image and a subview of the dummy container UIView.
It's been awhile, but I think your addTarget needs to take the object that contains the doHelp: selector, like so:
[helpButton addTarget:self action:#selector(doHelp:)];
assuming somewhere in that same View you have:
- (void)doHelp: { }
passing nil to addTarget means that you're sending that selector to no recipient.
The problem is your addTarget:nil there. The selector you gave it for action is just a message it'll send to its target. You didn't give it a target, so it doesn't know what to do with that message. You probably want to pass in self instead of nil there.
I came across this while googling for a solution to the same problem. At least with the 3.x SDK, all you have to do is set the UserInteractionEnabled property of the UIImageView to YES.
Thanks for posting your discovery about the problem, I wouldn't have even thought to look at that one.
I had a similar problem where Buttons were outside of the view and did not receive tap messages
what helps is to set background colour of the parent view, to see that button is outside of it:
...
[buttonParentView addSubview: myButton];
buttonParentView.backgroundColor = [UIColor cyanColor];