I am trying to update a label on view controller 1 by pressing a button on different view controller 2. I have this IBAction in the view controller 2:
- (IBAction)done:(id)sender {
DropPinVC * vc = [[DropPinVC alloc]init];
NSString *updatedLabel = [[NSUserDefaults standardUserDefaults] stringForKey:#"Type Location"];
NSLog(#"Updated Label = %#", updatedLabel);
vc.TypeLabel.text = updatedLabel;
[self closeScreen];
}
However, the label on view controller 1 does not update. Does anybody know a solution to this problem?
vc is a new instance of DropPinVC class declared in the scope of the action posted, and is not the same instance as the one you want to update.
One way to achieve this is to keep a pointer to the first view controller.
In order for viewController2(vc2) to update a UILabel that is owned by viewController1(vc1), vc2 needs a reference to vc1 so it can access the label.
Add a property to vc2 of type DropPinVC
#property (nonatomic, strong) DropPinVC *vc1Ref;
Assuming vc1 allocates and initialises vc2 then where after this happens assign the vc1Ref property.
vc2.vc1Ref = self;
Now in the IBAction, your code can now access the correct instance and update the correct label.
- (IBAction)done:(id)sender {
NSString *updatedLabel = [[NSUserDefaults standardUserDefaults] stringForKey:#"Type Location"];
NSLog(#"Updated Label = %#", updatedLabel);
self.vc1Ref.TypeLabel.text = updatedLabel;
[self closeScreen];
}
Related
Firstly, I've already tried to search for solutions online but none works for me and I'm thinking since I'm using ECSlidingViewController to navigate around the app, I can't utilise the prepareForSegue method thus, my problem may need a different approach.
I have a class called viewInits which holds properties in the .h file that I want allow other classes to set and get it's values. In this case, the property is an NSString *navBarTitle.
In ClassA, I have a tableView:didSelectRowAtIndexPath: method, where I
Create an ViewInits class object - *viewInits.
I then set the setNavBarTitle: to the value of [self.MenuRowsArray objectAtIndex:indexPath.row].
In the next line, I did an NSLog to check and yes, viewInits.navBarTitle now holds the value I desire.
In ClassB's viewDidloadMethod, similarly, I created a ViewInits object - *viewInits and did an NSLog check for viewInits.navBarTitle. But it returns (null). What seems to be the problem here?
Here is the code for how I'm trying to pass the NSString. What am I doing wrong?
viewInit .h
#interface ViewInits : NSObject
#property (strong, nonatomic) NSString *navBarTitle;
#end
ClassA.m tableView:didSelectRowAtIndexPath: method:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *identifier = [self.MenuRowsArray objectAtIndex:indexPath.row];
UIViewController *newTopViewController = [self.storyboard instantiateViewControllerWithIdentifier:identifier];
// *---------- Assign identifier to NSString viewInits ----------*
ViewInits *viewInits = [[ViewInits alloc] init];
[viewInits setNavBarTitle:identifier];
NSLog(#"%#", viewInits.navBarTitle);
// *---------- Assign identifier to NSString viewInits ----------*
[self.slidingViewController anchorTopViewOffScreenTo:ECRight animations:nil onComplete:^
{
CGRect frame = self.slidingViewController.topViewController.view.frame;
self.slidingViewController.topViewController = newTopViewController;
self.slidingViewController.topViewController.view.frame = frame;
[self.slidingViewController resetTopView];
}];
}
ClassB.m
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
// *========== ECSlidingViewController ==========*
self.view.layer.shadowOpacity = 0.75f;
self.view.layer.shadowRadius = 10.0f;
self.view.layer.shadowColor = [UIColor blackColor].CGColor;
if (![self.slidingViewController.underLeftViewController isKindOfClass:[MenuViewController class]])
{
self.slidingViewController.underLeftViewController = [self.storyboard instantiateViewControllerWithIdentifier:#"Menu"];
}
[self.view addGestureRecognizer:self.slidingViewController.panGesture];
// *========== ECSlidingViewController ==========*
ViewInits *viewInits = [[ViewInits alloc] init]; // Create ViewInit class object
self.navBar.topItem.title = viewInits.navBarTitle;
NSLog(#"%#", viewInits.navBarTitle); // <<--- This always ends up null. What's wrong?
}
Your help are much appreciated. Thank you.
If you want to use ViewInit as a common store of settings it should be a singleton so that all other instances in the app can get it. Currently you're creating a new instance each time you want to use it, so the new instance doesn't have any of your previous settings.
Aside, I know what the sliding view controller is, I ask about it because you may be using it incorrectly. If you have a view controller which is the current top view controller and it changes the top view controller (class A might be doing this, not sure) then the reference self.slidingViewController will stop working part way through your code.
(IBAction)captureButton:(id)sender {
captureButton.hidden = YES;
cancelButton.hidden = YES;
currImage = [signatureViewController imageWithView:self.view];
NSLog (#"image %#",currImage);
imgView = [[UIImageView alloc]initWithFrame:CGRectMake(150,100,300,350)];
imgView.backgroundColor = [UIColor blackColor];
imgView.image = currImage;
[self.view addSubview:imgView];
}
Capturing the imageView now need to pass this to signView in first Controller.
You can pass the image from one view controller to other view controller in many ways,Out of which some are listed below
In the app delegate create one imageview object.Declare property &
synthesize of it to access it in other classes. Now Create App
delegate share instance & set the image view object of app delegate
in captureButton method of second view controller. To access the
same image again create shared instance of app delegate file in
first view controller and use the app delegate image view property
to get the image.
Second way is by using the delegates methods
//Declare delegate in second view controller
#protocol SecondViewControllerDelegate
-(void)setTheImage:(UIImage *)img
#end
//Declare property of delegate protocol
#property (assign)id<SecondViewControllerDelegate> delegate;
//synthesize the variable
#synthesize delegate;
//Extend SecondViewControllerDelegate in first view controller by importing secondviewController in first view controller
#import secondviewController.h
#interface firstviewController : UIViewController<SecondViewControllerDelegate>
// Now wherever you are creating object of SecondViewController set the delegate as follows lets say objSecondViewController is object of your view controller
objSecondViewController.delegate=(id)self;
//Now define delegate method of SecondViewControllerDelegate
-(void)setTheImage:(UIImage *)img
{
//here set the image img to your image view present in first view controller
}
//Now lastly in second view controller in captureButton function call the function
[delegate captureButton:currImage];
Third way is to use the global declaration of the first view
controller & set the image view in the captureButton by declaring
the property & synthesize of imageview of first view controller
I Have done this using NSUser defaults..
In the secondViewController:
-(IBAction)doneAction:(id)sender
{
imgView.image = currImage;
NSData *imageData = UIImagePNGRepresentation(currImage);
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:imageData forKey:#"imageDataKey"];
NSLog (#"Data Saved");
}
and i have assigned this saved image to the imageview in the firstController in -(void)viewWillAppear: Method
I'm trying to use storyboard and get things working properly. I've added a a Container View to one of my existing views. When I try to add a reference to this in my view controller .h file (ctrl-drag), I get a IBOutlet UIView *containerView. How do I get a reference to the container view's view controller instead? I need the container view controller so I can set it's delegate to my view's controller so they can "talk" to each other.
I have my story board setup as:
And its referenced in my .h file as:
Notice in the .h that is is a UIView, not my InstallViewController for the view. How do I add a reference to the view controller? I need to be able to set its delegate.
There is another solution by specifying an identifier for the embed segue(s) and retrieve the corresponding view controllers in method prepareForSegue:
The advantage of this way is that you needn't rely on a specific order in which your child view controllers are added due to the fact that each child view controller is embedded via an unique segue identifier.
Update 2013-01-17 - Example
- (void) prepareForSegue:(UIStoryboardSegue*)segue sender:(id)sender
{
// -- Master View Controller
if ([segue.identifier isEqualToString:c_SegueIdEmbedMasterVC])
{
self.masterViewController = segue.destinationViewController;
// ...
}
// -- Detail View Controller
else if ([segue.identifier isEqualToString:c_SegueIdEmbedDetailVC])
{
self.detailViewController = segue.destinationViewController;
// ...
}
}
c_SegueIdEmbedMasterVC & c_SegueIdEmbedDetailVC are constants with the corresponding ID of the segue IDs defined in the storyboard.
When you add a container view the xcode calls the UIViewController method addChildViewController:
In your case, you can get the container ViewController looking for it on the SplashViewController's list of childViewControllers, something like this:
for (UIViewController *childViewController in [self childViewControllers])
{
if ([childViewController isKindOfClass:[InstallViewController class]])
{
//found container view controller
InstallViewController *installViewController = (InstallViewController *)childViewController;
//do something with your container view viewcontroller
break;
}
}
I had the same doubt yesterday :)
The answer of Vitor Franchi is correct but could be more performant and convenient. Especially when accessing the child view controller several times.
Create a readonly property
#interface MyViewController ()
#property (nonatomic, weak, readonly) InstallViewController *cachedInstallViewController;
#end
Then create a convenient getter method
- (InstallViewController *)installViewController
{
if (_cachedInstallViewController) return _cachedInstallViewController;
__block InstallViewController *blockInstallViewController = nil;
NSArray *childViewControllers = self.childViewControllers;
[childViewControllers enumerateObjectsUsingBlock:^(id childViewController, NSUInteger idx, BOOL *stop) {
if ([childViewController isMemberOfClass:InstallViewController.class])
{
blockInstallViewController = childViewController;
*stop = YES;
}
}];
_cachedInstallViewController = blockInstallViewController;
return _cachedInstallViewController;
}
From now on access the child view controller that way
[self.installViewController doSomething];
UIView* viewInsideOfContainer = installerView.subviews[0];
Will give you the UIView inside of the UIViewController that your controller UIView references. You can cast the subview to any type that inherits from UIView.
If the nib is loaded it will call addChildViewController as part of the initialisation process
so a performant solution could be also to overwrite
- (void)addChildViewController:(UIViewController *)childController
there you can catch your childController e.g. by comparing its Class and assign it to a property / ivar
-(void)addChildViewController:(UIViewController *)childController
{
[super addChildViewController:childController];
if([childController isKindOfClass:[InstallViewController class]])
{
self.installViewController = (InstallViewController *)childController;
}
}
This will save your from iterating trough the childViewControllers.
I am currently designing the structure for my first iPhone game and ran into a problem. Currently, I have a 'MenuViewController' that allows you to pick the level to play and a 'LevelViewController' where the level is played.
A UIButton on the 'MenuViewController' triggers a modal segue to the 'LevelViewController'.
A UIButton on the 'LevelViewController' triggers the following method to return to the 'MenuViewController':
-(IBAction)back:(id)sender //complete
{
[self dismissModalViewControllerAnimated:YES];
}
The problem is, I have a UILabel on the menu page that prints the number of total points a player has. Whenever I go back to the menu from the level, I want this label to automatically update. Currently, the label is defined programmatically in the 'MenuViewController':
-(void)viewDidLoad {
[super viewDidLoad];
CGRect pointsFrame = CGRectMake(100,45,120,20);
UILabel *pointsLabel = [[UILabel alloc] initWithFrame:pointsFrame];
[pointsLabel setText:[NSString stringWithFormat:#"Points: %i", self.playerPoints]];
[self.pointsLabel setTag:-100]; //pointsLabel tag is -100 for id purposes
}
self.playerPoints is an integer property of MenuViewController
Is there a way I could update the label? Thanks ahead of time!
This is a perfect case for delegation. When the LevelViewController is done, it needs to fire off a delegate method which is handled in the MenuViewController. This delegate method should dismiss the modal VC and then do whatever else you need it to do. The presenting VC should normally handled the dismissal of modal views it presents.
Here is a basic example of how to implement this:
LevelViewController.h (Above the Interface declaration):
#protocol LevelViewControllerDelegate
-(void)finishedDoingMyThing:(NSString *)labelString;
#end
Same file inside ivar section:
__unsafe_unretained id <LevelViewControllerDelegate> _delegate;
Same File below ivar section:
#property (nonatomic, assign) id <LevelViewControllerDelegate> delegate;
In LevelViewController.m file:
#synthesize delegate = _delegate;
Now in the MenuViewController.h, #import "LevelViewController.h" and declare yourself as a delegate for the LevelViewControllerDelegate:
#interface MenuViewController : UIViewController <LevelViewControllerDelegate>
Now inside MenuViewController.m implement the delegate method:
-(void)finishedDoingMyThing:(NSString *)labelString {
[self dismissModalViewControllerAnimated:YES];
self.pointsLabel.text = labelString;
}
And then make sure to set yourself as the delegate for the LevelViewController before presenting the modal VC:
lvc.delegate = self; // Or whatever you have called your instance of LevelViewController
Lastly, when you are done with what you need to do inside the LevelViewController just call this:
[_delegate finishedDoingMyThing:#"MyStringToPassBack"];
If this doesn't make sense, holler and I can try to help you understand.
Make a property self.pointsLabel that points to the UILabel, then you can just call something like [self.pointsLabel setText:[NSString stringWithFormat:#"Points: %i", self.playerPoints]]; to update the label with the new score
In your modal view header file, add the property:
#property (nonatomic,assign) BOOL updated;
Then in your main view controller, use didViewAppear with something like:
-(void)viewDidAppear:(BOOL)animated{
if (modalView.updated == YES) {
// Do stuff
modalView.updated = NO;
}
}
Where "modalView" is the name of that UIViewController that you probably alloc/init there.
Add more properties if you want to pass more info, like what level the user picked.
I have a main view with 3 buttons. Clicking on any of the buttons adds a SubView.
The buttons have different titles and are all linked to IBAction "switchView"
The "switchView" code is below.
- (IBAction)switchView:(id)sender{
secondView *myViewController = [[secondView alloc] initWithNibName:#"secondView" bundle:nil];
[self.view addSubview:myViewController.view];
}
The "secondView" loads up correctly and everything works well.
The problem is I want to be able to know which button was the Sender.
I don't want to create 3 subviews, one for each button. The code and XIB would be absolutely the same>
The only difference would be a variable that I would like to set up in the second view (viewDidLoad method) depending on who is the Sender (which button was clicked)
Is this possible? Or I would need to create 3 subViews - one for each button?
Your help is greatly appreciated!
You can identify different buttons with the tag property.
e.g. with your method:
-(IBAction)switchView:(id)sender {
UIButton *button = (UIButton*)sender;
if (button.tag == 1) {
//TODO: Code here...
} else if (button.tag == 2) {
//TODO: Code here...
} else {
//TODO: Code here...
}
}
The tag property can be set via the InterfaceBuilder.
Hope this helps.
I think you can solve in 2 ways:
Create a property like:
#property (nonatomic, strong) IBOutlet UIButton *button1, *button2, *button3;
in your viewcontroller and link the buttons to them as referencing outlet on the XIB.
Give a different tag to each button on your xib and ask for the tag of the sender with UIButton *b=(UIButton*)sender; b.tag; like Markus posted in detail.
Solving my problem it all came down to transferring data between the mainView and subView.
In my mainView.h I declared an NSString and its #property
...
NSString *btnPressed;
}
#property(nonatomic, retain) NSString *btnPressed;
...
then in my mainView.m inside the switchView method I did this:
- (IBAction)switchView:(id)sender{
secondView *myViewController = [[secondView alloc] initWithNibName:#"secondView" bundle:nil];
btnPressed = [NSString stringWithFormat:#"%i", [sender tag]];
[myViewController setBtnPressed:self.btnPressed];
[self.view addSubview:myViewController.view];
}
This line in the code above actually takes care of transferring the data to the newly created subView:
[myViewController setBtnPressed:self.btnPressed];
Then in my secondView.h I declare exactly the same NSString *btnPressed and its #property (though this a completely different object than the one declared in main)
Then in my secondView.m I get the value of the button pressed I'm interested in.
- (void)viewDidLoad {
[super viewDidLoad];
int theValueOfTheButtonPressed = [self.btnPressed intValue];
}
This works well.
Don't forget to #synthesize btnPressed; as well as [btnPressed release]; in both mainView.m and secondView.m