My Setup
I have a ViewController, where users type some sort of text in there. Call it InputViewController.
I have a UIView (in a separate class), where I draw a navigation bar that has a gradient (I override drawRect for Core Graphics, hence I need to to have in a separate class) which has a button. The button takes you to a MapViewController, which allows you to add a location tag to your input. Once a location tag is added, I would like to change the button's image.
My Problem
Once the button is tapped, I need to send the user's input to the MapViewController, where a delegate is also implemented and will pass back some information back to the InputViewController. The issue here is that the button resides in the separate UIView. One way to do this is pass the UIView the information once they are set, which in turn would be passed to the MapViewController once the button is tapped. The problem here would be the delegate as the delegate needs to return to the InputViewController and not the `UIView.
I was wondering if its possible to move the UIView into the InputViewController, including the drawRect method for that view. If so, how can I do that? If not, what are other ways/suggestions I can do to have the above set up?
I guess you need to use NSNotifications for sending messages to your classes. See this.
Related
I have a problem, I want to show right delete confirmation button of my UITableView's cell. Swipe to delete works just fine but I also want this to happen without swiping.
I would like to change cell's state from default to showing delete confirmation. There is bool property showingDeleteConfirmation but it's read only.
[self setEditing:YES animated:YES];
From custom cell's class doesn't do anything.
How to change cell's state to showing delete confirmation without swipe?
i.e. after swipe gesture on a cell is recognized what is being called? I would like to call it manually.
That is a delegate method meaning you should not call it yourself as that is a part of the process handles by the tableView class.
Instead you'll want to override the call class, prepare the method to show your button (or whatever you want to show) and animate other views trimming their frames. Doing that you'll understand the difference between the delegate and instance messages as you'll probably need to notify the tableView or it's delegate that your method is complete, the button is shown and other views are also animated.
Assume you do not have a UIController to do the job. From inside the UIView .. how would you replace self with another UIView?
It's not very clear what you are trying to do from your question. UIController is not a class, for instance.
Ideally your app should be structured something like this:
UIViewController subclass
Controls a set of objects that are all on screen at one time. For example, any number of UITextFields, UIButtons, UIViews and UILabels.
has methods (IBActions and other delegate methods) which are triggered by user interaction with the controls and inputs.
has IBOutlets which allow it to manipulate what the user sees on screen. For instance an IBOutlet attached to a UILabel allows changing the text when a user presses a button.
UIView is only generally subclassed if you need custom drawing code, or some kind of custom control. Don't put application logic here if you can help it, and you can usually help it.
You can have multiple UIViewControllers but they usually function very independently. Often View Controllers don't maintain references for other view controllers. If they do it's loose couplings like the delegate pattern.
Bottom line: if you have two views controllers that need to communicate with each-other, you need to have a reference to one from the other. This usually occurs in the form of a property on one or both of the view controllers, and is connected either by interface builder or at run time when you create them.
You can add another subview using self.addSubview: you may also want to check self.bringSubviewToFront:
For more information, check the docs:
http://developer.apple.com/library/ios/#documentation/uikit/reference/uiview_class/uiview/uiview.html
Hi I have a quiz app that I am working on, and on my RootViewController I have two buttons with action methods, now when I press on one of the buttons I get my questionViewController and text is loaded into specific fields, I do this by using the viewDidLoad method. When I go back to the RootViewController and click on a different button I want to show the same questionViewController but with different text, how can I go about doing this?
I just finished a project with similar requirement. One way to do this is to use static variable and class method in your questionViewController class.
You could implement viewDidAppear: on your questionViewController, and set the text there instead of viewDidLoad.
You could also implement a method on questionViewController, that updated the text fields, and call this method from the RootViewController.
Must I always resignFirstResponder for a UITextView? Or, will this happen automatically when its view controller disappears?
I'm asking because I'm having an issue similar to iPhone Objective-C: Keyboard won't hide with resignFirstResponder, sometimes, where the keyboard stays up even when the nav controller pushes and pops other view controllers. The keyboard works, and when I hit done, it unfocuses the UITextView (i.e., the cursor disappears), but the keyboard stays up.
I never found out why this is happening, but maybe it's due to not doing resignFirstResponder before pushing another view controller, but I thought it was optional?
At a total guess, the UITextView has a reference to the view controller (as its delegate) but does not retain it. When you go to the next screen, the controller is dealloced and then the UITextView (which has perhaps been retained by something else) tries to call back to the dealloced controller and crashes. When you call resignFirstResponder, you reverse the order this happens, and therefore no crash.
The way round this to add a textView.delegate = nil call in your view controller's dealloc method - obviously put it before you release the text view.
The contract between a UITextView and it's delegate says that the delegate will send -resignFirstResponder when the text view is done editing. This informs the framework that the view is done editing, fires the events relating to that (willEndEditing and didEndEditing), and allows other parts of the responder hierarchy to react accordingly. Failing to do so might work, but it's not following the contract (that's all a protocol is) it agreed to.
I don't think you have to because the Xcode Sample UICatalog UITextField doesn't call resignFirstResponder before the TextViewController is popped.
The reason the keyboard got stuck for me is that I was having the same view controller present two view controllers modally at the same time, one after the other. UIKit didn't like that.
Calling resignFirstResponder makes sure that the text property contains the actual text shown in the control.
Depending on the state this is not always necessary, but if your controls have resigned first responder, you know that you're working with valid data.
Here's a simplification:
I have an application with several buttons. If it is the first time the application is launching, I want to do some special things. In my AppController class, which is a delegate of NSApp, I use the delegate method -applicationDidFinishLaunching: to perform the test. After I've detected that it is the first time, I first want to access some IBOutlets. Then, I'd like to be able to get mouse events for each button, so that I can do other things.
I can't figure out want to do with the classes. I'd like to make a new class (FirstLaunch) for the first launch, but I'm not sure what to call from AppDelegate. Also, to get mouse events, shouldn't I be a sublass of the buttons, and considering that I have multiple buttons, I'm confused. I could probably tackle these issues one-by-one, but taken all together, they're confusing me.
Broken down, I need to access & manipulate IBOutlets I have set in IB, determine when buttons are clicked (and which button was clicked). I'd like to be able to do this from another class so as to not clutter up the AppDelegate.
Thanks for the help!
To be more clear, what I'm actually trying to do is to use Matt Gemmel's MAAttachedWindow to put up a help bubble by a button. When the button is clicked clicked, the bubble disappears and another one is put somewhere else. The bubbles will be attached to controls in the main window.
I'm guessing you want to show some additional user interface on the first launch? If it's a separate window, I'd advise creating a subclass of NSWindowController. Add a new NIB file for the first-run user interface to your project and change the class of the File's Owner object to FirstLaunch. Control-drag a wire from the File's Owner delegate onto the window to connect it with the window outlet.
You create IBOutlets by adding an instance variable to the class. If your app will only run on Leopard or higher, it's better to declare your outlets like this:
#interface FirstLaunch : NSWindowController {
NSTextField *myTextField;
}
#property (nonatomic, retain) IBOutlet NSTextField *myTextField;
#end
In Interface Builder, you'll control-drag a wire from the File's Owner onto the control to associate it with that outlet. Make sure that you release your reference to each IBOutlet in your class's dealloc method (if you're not using garbage collection) or else your app will leak memory.
Buttons send action messages when they're clicked, so you'll need to provide an action method for the button to call. You do that by declaring a method with a signature like this:
- (IBAction)myButtonClicked:(id)sender;
In Interface Builder, you'll control-drag a wire from the button onto your window controller and choose the myButtonClicked: method.
To make all this work, you'll need to create an instance of the window controller and tell it to load the NIB file at runtime. So, in your AppDelegate class, when you've determined that this is the first launch, you'll do this:
FirstLaunch *firstLaunchController = [[FirstLaunch alloc] initWithWindowNibName:#"nameOfNibFile"];
[firstLaunchController show:self];
You'll probably want to keep the reference to the window controller in an instance variable instead of a local variable like I've done here. And, depending on your application, it may make more sense to show this as a sheet. But once you've made it this far, you'll be able to figure out how to do that on your own.
Then, I'd like to be able to get mouse events for each button, so that I can do other things.
Don't worry about the mouse. There may not even be a mouse (think of the ever-popular tablet-Mac rumor).
I'd like to make a new class (FirstLaunch) for the first launch, but I'm not sure what to call from AppDelegate.
You make your own methods here. You'll probably make it a singleton*; then, you'll implement a method named something like runFirstLaunchPanel:, which will be an action method (more on those in a moment):
- (IBAction) runFirstLaunchPanel:(id)sender;
Instantiate the object in the nib, then, from your app delegate, call the action method with nil as the sender.
The reason to put the object in your nib and make the method an action method is that this makes it easy to hook up a menu item to it, so that the user can re-run the first-launch panel at a later time. (For example, if it's a Starting Points window, you might connect the New menu item to this action instead of the default one.)
*Yes, I've seen the articles about singletons, and I agree with them. In a case like this, it's OK.
Also, to get mouse events,
This is the wrong way of thinking about it. What you need to do is set your button up to send a message to your controller to make the controller (probably AppDelegate) do something. The message you want the button to send is an action message.
Implement an action method in the object that owns the nib containing the window with the buttons. Declare this method in the class's header, then connect the button to it in IB by right-clicking on your controller and dragging from the correct action method's circle to the button.
This is called the target-action paradigm, and it insulates controller responsibilities (doing things) from the views that ordered them. Because each action method does only one thing, you can have a button, a menu item, and even another controller (your app delegate, above) send the same action message, and the receiving controller won't have to care which control is sending the action, because it already knows what it has to do.
shouldn't I be a sublass of the buttons,
No. You very rarely create subclasses of anything other than NSObject (or, for model objects in Core Data, NSManagedObject) in Cocoa.
Note that I said “rarely”, not “never”. You will have to make the occasional subclass, especially if you want to create custom or customized views and cells (and, maybe, customized windows). However, subclassing is not necessary in Cocoa to the degree that (I hear) it is in some other frameworks on other platforms.
and considering that I have multiple buttons, I'm confused.
The target-action paradigm means you don't have to create one button subclass per button. One controller class implements all the actions, and the stock buttons, because you've hooked them up in IB, simply tell the controller “do this”.
Broken down, I need to access & manipulate IBOutlets I have set in IB,
Probably not. At least, not as much as you think you do.
determine when buttons are clicked (and which button was clicked).
Nope. The buttons will worry about being clicked; you just worry about setting them up to send, and then responding to, their action messages.