Hy
i have two classes uiviewcontroller and uiview. I have one view controller. Inside i have uiview. Inside uiview i have textfield and when i write a text and click done i need to refresh uiviewcontroller.
I tried with this in uiview class:
-(IBAction)textFieldReturn:(id)sender
{
ViewController *vc = [[ViewController alloc] init];
[vc viewDidLoad];
}
i need refresh the same as you click the button and open viewcontroller.
I am guessing you mean that you want to "refresh" the view, not the view controller. To do that simply call [self setNeedsDisplay] from the view, or [self.view setNeedsDisplay] from the view controller. Also make sure that the textfield is a subview of the uiview. Either do that in the nib file or in code by calling [self addSubview: (textfield here)].
Also, if you want to access the view controller from the view you will need to create an IBOutlet, simply allocating a new ViewController object within the view does not mean that the created view controller controls the view. Hopefully that makes sense. I'd recommend going through some ios starter tutorials as well. Just google that there are a lot.
Related
I have a UIViewController (HomeView) that shows my UIView called GameView via a Segue.
[self performSegueWithIdentifier: #"segue_playgame" sender: self];
The GameView calls a UIView (PauseView) when the use presses a button. This pause view is shown via just adding the PauseView to the UIView.
UIView *pv = [[PauseView alloc] initWithFrame:self.view.bounds];
[self.view addSubview:pv];
To remove the PauseView I call
[pv removeFromSuperview];
Is there a way to call an "End Game" method in the PauseView that will remove both the PauseView and the GameView taking the user back the HomeView (UIViewController)?
And side note, is there a better way to handle showing views and removing them? Or is how I am doing it pretty much standard?
What you are missing here is a UINavigationController. From the official documentation:
The UINavigationController class implements a specialized view
controller that manages the navigation of hierarchical content. This
navigation interface makes it possible to present your data
efficiently and makes it easier for the user to navigate that content.
You generally use this class as-is but you may also subclass to
customize the class behavior.
With your views managed by the UINavigationController stack you can use:
- (NSArray<__kindofUIViewController *> *)popToRootViewControllerAnimated:(BOOL)animated
To pop back to the root view controller which in your case is your home view controller.
I have a view controller in my application where on my screen I have a UIView that the user is required to tap on. When they do that, I want to call another viewController's view, and display it on the screen for the user. Unfortunately, I am having trouble displaying the view.
The name of my viewController that I am making the call from is called "MainViewController", and the ViewController whose view I wish to display is called, "NextViewController"
Here is my code from where I make the call:
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"I was touched.");
_nextView = [[NextViewController alloc] init]; //this code is not being called
[self.view addSubview:_nextView.view]; //neither is this being called
}
Where _nextView is a property that I declare in the .h file of MainViewController.
This method is being called, but for some reason because I am able to see the log statements print to the output, but for some reason I am unable to call the lines after that. What am I doing wrong?
You shouldn't add the view of another view controller to your view without making that view controller a child view controller. If you just want a view, then set one up in a xib file and add it to your view as a subview. If you want to use a view controller, then you should present it modally, and dismiss it when you're done. This kind of situation where you want to gather some info from the user to use in your app, is an appropriate place to use a modal view controller. MainViewController should set itself as the delegate of NextViewController, and NextViewController should define a delegate protocol to send the data back to MainViewController.
To present it modally, do this:
_nextView = [[NextViewController alloc] initWithNibName:#"your nib name here" bundle:nil];
[self presentViewController:_nextView animated:YES completion:nil];
Are you using a Navigation Controller? Or Storyboards? One way of displaying another view controller would be like this:
[self presentViewController:_nextView animated:YES completion:^{
}];
A couple of things:
- If your NSLog gets called, then so do the other two lines you say do not.
- I assume you mean you want to display the other view controller on screen, not display the other view controller's view on the first view controller. These are two very different things, the second of which you wouldn't want to do.
in my iPad-app I am trying to present one of my views with a modal formsheet-style.
Here's some code:
-(void)present
{
SecondViewController *modal = [[SecondViewController alloc]init];
modal.modalPresentationStyle = UIModalPresentationStyleFormSheet;
[self presentModalViewController:modal animated:YES];
}
I am using Storyboard, and I have put stuff like a textView and toolbars in the view I'd like to show. I have set the right class in Identity Inspector, and in the class-files I have checked that it's the right view appearing with putting NSLog(#"Right view");
When calling the void present, a view is appearing, but only as a dark-white square. Nothing og my content from Storyboard is in it, I even tried changing the background color of the view and the textView to see if something was just outside the square, but the whole thing stayed white. It feels like it's not using the view I created in storyboard, but I have set it to the correct class, and the NSLog gets printed out when calling it. I have not connected the two views in any way in Storyboard, the SecondViewController is just floating around, so that might be the problem? The button that calls for -(void)present is created programmatically, so I can't ctrl+drag it to the button either.
Why is it showing an empty version of my class?
In the "Identity Inspector" set a "Storyboard ID" for your ViewController, and then present it like this:
-(void)present
{
SecondViewController *modal = [self.storyboard instantiateViewControllerWithIdentifier:#"myStoryboardID"];
modal.modalPresentationStyle = UIModalPresentationStyleFormSheet;
[self presentModalViewController:modal animated:YES];
}
And if you're using iOS6, presentModalViewController:animated: is deprecated, so use this:
-(void)present
{
SecondViewController *modal = [self.storyboard instantiateViewControllerWithIdentifier:#"myStoryboardID"];
modal.modalPresentationStyle = UIModalPresentationStyleFormSheet;
[self presentViewController:modal animated:YES completion:nil];
}
Your problem is that you're assuming the program will intrinsically know where to find the, already laid out, view for this controller when that's simply not how storyboards work. The code you list about will create a view controller, but without an associated view it will simply show as a black square.
There's a few ways to solve your dilemma:
Add the modal transition as a segue in the view controller, this would be the simplest way and is what iOS storyboards expect you to do.
Move the view from the storyboard to an external .xib and call the initWithNibName:bundle: method to load this as your view controller's view. This is the best solution if you just want to programmatically load the view.
Load the view from your storyboard programmatically with the instantiateViewControllerWithIdentifier: method, this is probably a bad idea as it goes against the design of storyboards.
I can elaborate on those if you want.
I am trying to get a popup effect and want to design the popup view in another view controller so i can use the xib to do it.
When i used the presentViewController or pushViewController and set the background to transparent, i end up seeing the Window's background color.
I tried this code to add subview to the navigation controller's view so that i can have the Info view cover the entire screen with a transparent background. I also have tab bar to cover up as well.
InfoVC *vc = [[InfoVC alloc] initWithNibName:#"InfoVC" bundle:nil];
[self.navigationController.view addSubview:vc.view];
My problem is inside my InfoVC when i try to dismiss it, the app will crash with some EXC_BAD_ACCESS message:
[self.view removeFromSuperview];
EDIT:
I found a way to stop it crashing but setting the InfoVC as a property in the MainVC. I think the reason for crash is when i call "self.view" in the action inside the InfoVC, it doesn't know that self is the InfoVC inside MainVC.
InfoVC *vc = [[InfoVC alloc] initWithNibName:#"InfoVC" bundle:nil];
[self.navigationController.view addSubview:vc.view];
No no no no. Never never do that.
There is an elaborate dance that you must traverse in order to put a view controller's view inside another view controller's view (or remove it afterwards) if it doesn't come with built-in facilities for doing this (the way a UISplitViewController does, or the way a navigation controller manages the views of the view controllers that are pushed and popped within it).
Read up on customer container controllers. One of the examples from my book is here:
https://github.com/mattneub/Programming-iOS-Book-Examples/blob/master/ch19p556containerController/p476containerController/ViewController.m
Shouldn't you be using the following to remove the view from its superview?
[vc.view removeFromSuperview];
You can never have a UIView remove it's subviews, the subviews themselves must remove themselves from it's superview. You can easily loop through subviews and have them removed like so
for (UIView *view in vc.view.subviews) {
[view removeFromSuperview];
}
Docs for reference:
http://developer.apple.com/library/ios/#documentation/uikit/reference/uiview_class/uiview/uiview.html
After a "modally" presented view controller has appeared the views under the now presented view controller will be removed; this saves memory, and eases rendering. In your case, though, you also end up seeing the window behind the "modally" presented view.
The natural, and seemingly logical, next step is to simply take one view controller's view and cram it into another. However, as you have discovered, this is problematic. With the newly inserted view safely retained by the view hierarchy it is safe, but the new view controller is not so lucky, it is quickly deallocated. So when this new view tries to contact its controller you will get an EXC_BAD_ACCESS and crash. One workaround, again as you have found, is to simply have the original view controller keep a strong reference to the new view controller. And this can work... badly. There's still a good chance you will get an UIViewControllerHierarchyInconsistencyException.
Of course if you simply want to add a small view you create in IB you don't need to use a view controller as the "File's Owner" and there are many examples of creating an instance of a view from a xib file.
The more interesting question here is, "How would/does apple do it?" Apple consistently says that a view controller is the correct controller for an encapsulated unit of work. For example, their TWTweetComposeViewController, you present it, and it seems to float. How?
The first way of accomplishing this that comes to my mind is to have a clear background that isn't clear. That is, create an image of the screen before the presented view controller appears and set that as the background before the presenting view is removed. So for example(Explanation to follow):
QuickSheetViewController.xib
QuickSheetViewController.h
#import <UIKit/UIKit.h>
#interface QuickSheetViewController : UIViewController
- (IBAction)dismissButtonPressed:(id)sender;
#end
QuickSheetViewController.m
#import "QuickSheetViewController.h"
#import <QuartzCore/QuartzCore.h>
#implementation QuickSheetViewController {
UIImage *_backgroundImage;
}
-(void)renderAndSaveBackgroundImageFromVC:(UIViewController *)vc{
UIGraphicsBeginImageContext(vc.view.bounds.size);
[vc.view.layer renderInContext:UIGraphicsGetCurrentContext()];
_backgroundImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
}
-(void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];
// save an image of the current view, and set our background to clear so we can see the slide-in.
[self renderAndSaveBackgroundImageFromVC:self.presentingViewController];
self.view.backgroundColor = [UIColor clearColor];
}
-(void)viewDidAppear:(BOOL)animated{
[super viewDidAppear:animated];
// Time to use our saved background image.
self.view.backgroundColor = [UIColor colorWithPatternImage:_backgroundImage];
}
-(void)viewWillDisappear:(BOOL)animated{
[super viewWillDisappear:animated];
// Set our background to clear so we can see the slide-out.
self.view.backgroundColor = [UIColor clearColor];
}
- (IBAction)dismissButtonPressed:(id)sender {
[self dismissViewControllerAnimated:YES completion:nil];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation{
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
#end
The majority of this example hinges upon the renderAndSaveBackgroundImageFromVC: method. In which, we create a graphics context render the view we are about to cover into it, and then create a UIImage to later (in viewDidAppear) use as a background.
Now simply use it like:
QuickSheetViewController *newVC = [[QuickSheetViewController alloc] initWithNibName:nil bundle:nil];
[self presentViewController:newVC animated:YES completion:nil];
You will see through the background just long enough for the animation to happen, then we use our saved image to hide the removal of the presenting view.
I'm pretty new to iOS development, and I'm trying to develop a simple app in which a button changes the subviews. I have a base RootViewController, which displays MiddleView correctly on init. MiddleView has a single button, labeled "First," which is connected (in Interface Builder) to RootViewController's -openFirstView.
Here's how MiddleView is displayed within RootViewController's -viewDidLoad
MiddleViewController *middleTemp = [[MiddleViewController alloc] initWithNibName:#"MiddleView" bundle:nil];
self.middle = middleTemp;
self.middle.rootViewController = self;
[self.view addSubview:middle.view];
[middleTemp release];
So I have the following ViewControllerss: MiddleViewController and FirstController which control MiddleView and FirstView respectively, and a RootViewController which switches between the two.
I've linked this by placing a RootViewController reference in MiddleViewController, and adding
self.middle.rootViewController = self;
to RootViewController's -viewDidLoad.
-(IBAction)openFirstView:(id)sender{
[middle.view removeFromSuperview];
[self.view addSubview:firstController.view];
}
Note: I've tried initializing firstController within -openFirstView, and when it initially didn't run, I moved the initialization to -viewDidLoad and have proven that it is initializing from the nib correctly by displaying FirstView directly in -viewDidLoad
Where firstController is loaded to a reference earlier in code. However, when I run the code and click the button, nothing in the view changes.
I've done some more diagnosing. I've found specifically that -ViewDidLoad in rootViewController is being called twice, once on the original load and once on the first click of the button, and I'm not sure exactly why.
It seems you haven't inialize your firstView in the below method
-(IBAction)openFirstView:(id)sender{
[middle.view removeFromSuperview];
//First initialize the firstController
[self.view addSubview:firstController.view];
}