Alright, so here is what I am trying to do. I have a UITextField. When I single tap it, I want to call one of my methods. When I double tap (tap it twice with 1 finger) it, I want to edit the text field (as though I had single tapped it on a normal UITextField.)
I am not sure how to go about this. I was thinking of sub-classing UITextField and trying to intercept the touch event as it is sent, but I can't figure out which methods to override to do this. Which methods should I override and how?
Or, if there is a better way to do this, let me know! I'm all ears, and not sure how to proceed.
This would involve several steps:
1.) Add a NSBoolean property that keeps track of whether the user has already tapped the field once recently (you get to decide what recently means here).
2.) Implement the textFieldShouldBeginEditing: method of the delegate assigned to your UITextField. If the user has tapped twice in quick succession (detectable by checking whether or not the boolean property is true), then return YES. If not, call your method, and then return NO.
Related
I'm making an app and I want the user to be able to input text without having them actually click on a UITextField (have it open after the game ends for a scoreboard), is there some way to do that?
Call the following in the viewDidLoad of scoreboard, or whatever the entry point of that view is.
yourTextField.becomeFirstResponder()
Yes, just:
<#your_text_field#>.becomeFirstResponder()
after the game ends.
This will produce the "same" effect as a tap on the UITextField. If this is on a new UIViewController you can place it on viewDidAppear, otherwise you can assume everything is already loaded and simply call it anywhere.
I have an option menu where a user can change the application's settings. I need to track the changes. There is a DONE button, I want to make changes to the data model only when the button is pressed.
My question is, I am not sure the best way to track the changes. I don't want to introduce a giant if blocks in the doneButtonPressed button. Any general advice?
Well, the generic answer is: add callback to your controls in your options screen.
For example if you are using UISlider, then you have to customize it slightly. Probably create a subclass, that would receive touch events and then you redirect them to the delegate. OR you can use this one: RCSwitch
If you are using UIButton's then it's even easier: just add action to it.
After that you can create method like:
-(void) controlDidChange:(UIView*) control {
//mark changed items here
}
I have a UISegmentedController to allow a user to choose which order they want slides in my app to show up. Im wondering if anyone knows of a method to set it other than value did change. I have other methods that keep getting triggered in viewDidLoad while its being set to their previously selected index. I don't want the other methods triggered until a user changes it. Any suggestions?
Thanks in advance
The simplest way would be adding boolean to your class, e.g. canTrigger. And you can set it to YES, once user changes.
I am confused about the iPhone responder chain. Specifically, in the iPhone event handling guide http://developer.apple.com/iPhone/library/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/EventHandling/EventHandling.html, we have the following:
The first responder is the responder object in an application (usually a UIView object) that is designated to be the first recipient of events other than touch events.
But UIView is a subclass of UIResponder. And the UIResponder class reference says this:
- (BOOL)canBecomeFirstResponder
Return Value
YES if the receiver can become the first responder, NO otherwise.
Discussion
Returns NO by default. If a responder object returns YES from this method, it becomes the first responder and can receive touch events and action messages. Subclasses must override this method to be able to become first responder.
I am confused by the apparent contradiction. Can anyone clear it up for me?
For what it's worth, I did set up a simple view-based application, and call canBecomeFirstResponder and isFirstResponder on its view. Both returned NO.
The nomenclature can be confusing. Instead of "first responder" think of it as "initial event target" i.e. the object that is the first responder becomes the initial target for all events. In some APIs this is also called the "focus" although in the Apple APIs that is usually reserved to describe windows.
At any given time, there is only one first-responder/intial-event-target in the app. Only individual objects/instances can become a first-responder/intial-event-target. Classes can merely define if their instance have the ability to become a first-responder/intial-event-target. A class need only provide the ability to become the app's first-responder/intial-event-target if it make sense to do so. For example, a textfield obviously needs the ability to trap events so that it can use those event to edit itself. By contrast, a static label needs no such capability.
Whether a particular class inherits from NSResonder has no bearing on whether the class (or a specific instance of the class) will let itself be set as the first-responder/intial-event-target. That ability comes solely from the instances' response to the canBecomeFirstResponder message. The same instance can refuse to be the first-responder/intial-event-target under one set of conditions and then allow it later when conditions change. Classes can of course hardwire the status if they wish.
In other words, first-responder/intial-event-target is a status of a particular instance at a particular time. The first-responder/intial-event-target is like a hot potato or a token that is handed off from instance to instance in the UI. Some classes refuse to grab the hot potato at all. Some always do and others grab it sometimes and ignore it others.
What this means is that the basic UIView is not able to become first responder - it doesn't do anything with motion events, editing-menu messages, etc.
Some UIView subclasses (like UITextView) are able to become first responder, and you can write your own UIView subclass that does so too.
I am having quite a issue trying to change the cut/copy/paste behavior of the UITextView.
What I want to achieve is: detect when the user has pasted some text into the UITextView. When I detect this I will then check the data and do my thing.
According to the documents, I found out about UIResponder.
So I created an simple class that inherits UITextView.
in the .m file I create 1 function called.
-(void) paste:(id)sender{
NSLog(#"paste button was pressed do something");
}
But for some reason it never seems to fire. I could get the select statement working and tracing data.
-(void) select:(id)sender
1. Is this the correct way to detect Paste in a UITextView?
2. Right now I am tracking buy how many Characters UITextView changes and if its greater than one char then I suspect that it could be a paste operation. But since the iPhone can autocomplete words eg Wedn (goes to Wednesday) its possibly not a paste operation.
In Interface Builder, I selected my textView in my NIB file, and selected its "Class Identity" to my nearly created class before and I know that this file was working as a subclass but it just would not respond to the Paste event.
thanks.
UITextView has a view that handles the cut, copy, paste. It's UIWebDocumentView. So if UITextView is the first responder, UIWebDocumentView will get it first instead of your implementation. I would like to overwrite these functions so this is very frustrating.
Same thing happens to me too. Select (and copy sometimes) gets called but paste never.
I have simulated the behavior using textViewDidChange where I always verify the difference between the current text and the previous one. If there are more letters different and the text.length is bigger than it must have been pasted.
Hope Apple will fix this.
In case somebody still needs short and easy solution I'll share mine. I use wonderfull NSObject+REResponder category from REKit project. The solution is as easy as this:
- (void)hookMessageTextFieldPasteAction
{
void (^textFieldDidPasteBlock)(id receiver, id sender) = ^(id receiver, id sender)
{
NSLog(#"paste hook");
};
[self.messageTextField respondsToSelector:#selector(paste:) withKey:nil usingBlock:textFieldDidPasteBlock];
}
Yes your above code for paste is correct according to Apple's Documentation which refers to it here.
- (void)paste:(id)sender
I suspect you are implementing it in the wrong file. You should be implementing it in a file that is part of the 1st Responder chain. Have you subclassed the UITextView or are you using a vanilla one in your ViewController?
Hmmm I think the problem is that you may need to make your UITextView subclass become the delegate in order for the delegate method to work, because it's not by the looks of things. I'll try to find how i did that before.
Okay think i found it. I think you need to do this on your subclassed UITextField class:
#interface mySpecialTextFieldClass : NSObject <UITextFieldDelegate>
{
}
Adding that onto the end should work, give it a try!
What it does is makes your subclass become an object of a type that the delegate can send a notification to...it's polymorphism, unless someone wants to correct me here :)
One last thing to try John, in the ViewController which contains the IBOutlet to the UITextView, try calling this method on the instance of the UITextView:
[myUITextView setDelegate:self];
Just to throw something completely random in there try setting it to become first responder.
[myUITextView becomeFirstResponder];
This is called programming in the dark kiddies! And is a very bad way to program, but I admit I do it and sometimes it pays off :P lol.