I have a UIViewController that is a delegate of a UIScrollView called NumberLineScroll. I have set the delegate of the scrollview to be the view controller, but I am not getting any calls to scrollViewDidScroll: whenever the scrollview is scrolled. Here's the implementation:
The UIViewController header file (Game) :
#interface Game : UIViewController <LocDelegate, UIScrollViewDelegate, ResultsDelegate> {
...
NumberLineScroll* nline;
...
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView;
- (UIView*)viewForZoomingInScrollView:(UIScrollView*)scrollView;
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale;
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView;
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView;
and the component of the main file where the methods are implemented:
- (void)viewDidLoad {
...
nline = [[NumberLineScroll alloc] initWithFrame: CGRectMake(0, -50, 1024, 400)];
[nline setScrollEnabled:YES];
[nline setContentSize:CGSizeMake(4100, 400)];
[self.view addSubview:nline];
nline.delegate = self;
nline.locDelegate = self; //this is for a Ball imageview that is implemented in NumberLineScroll
...
}
and here's the implementation of the UIScrollView (NumberLineScroll):
header file:
#interface NumberLineScroll : UIScrollView {
NumberLine* nline;
Ball* ball;
id <UIScrollViewDelegate> delegate;
id <LocDelegate> locDelegate;
}
#property(nonatomic, assign)id <UIScrollViewDelegate> delegate;
#property(nonatomic, assign)id <LocDelegate> locDelegate;
There's nothing that's very relevant in the main file. The only programming in there that I do to affect the scrolling is turn the bounce off and to switch the scrolling off when the ball is being moved by the user, then on again when they finish. Also, the locDelegate isn't a problem since that works just fine. The main problem is that NumberLineScroll is making no delegate calls. Why is this?
Also, the NumberLine view in NumberLineScroll is the contentview for the scrollview, just for clarification.
My best guess here is that you're redefining the delegate property inside you NumberLineScroll class. Try deleting the #property(nonatomic, assign)id <UIScrollViewDelegate> delegate; line (and if you have a #synthesize statement in your *.m file delete that one too). Also, delete the following variable declaration: id <UIScrollViewDelegate> delegate;.
Finally, just as a side comment, when you conform to a protocol (like UIScrollViewDelegate) you don't declare the methods that you implement in your *.h file. So, the following lines in your Game class are not needed:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView;
- (UIView*)viewForZoomingInScrollView:(UIScrollView*)scrollView;
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale;
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView;
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView;
Hope this helps!
Related
I am a very beginner of objective c and I wanted to create a scene about using 2 child view controller in a master view controller which includes MapKit and TableView. I ve searched it on internet for 1 day and but I couldn't make any of solutions since I failed in different steps of each suggestions. I know that there are a lot of way to pass data between View Controllers and I thought the best way is using delegation logic in this situation. (let me know if I am wrong please). By the way, I can update or move the cursor onto specific location WHEN I set a dummy button on MapKitViewController, so MapKit part is not where I am failing at. I am pretty sure that the problem is about communication between 2 View Controllers which are active at the same time.
Problem:
Updating MapView by clicking a table row of TableView which includes location coordinate detail. Both children view are set on a MasterViewController by 2 container views.
Tried so far:
Created a method "goToLocation:(Location*) location" in MapViewController and sent parameters to this method from TableViewController. =>(Lat and Long parameters received by goToLocation() but MapKitView doesn't get updated)
Tried to create a delegate logic between MapView and TableView.=>(Probably I couldn't create it properly. Please see below)
What I want :
I want to know what part I am doing wrong. Is there a easy or proper way to achieve that ?
TableViewController.h
#class TableViewController; //define class
#protocol TableViewDelegate <NSObject> //define delegate protocol
//define delegate method to be implemented within another class
- (void) locationSelected: (TableViewController *) sender object:(Location *) location;
#end
#property (nonatomic, weak) id <TableViewDelegate> delegate; //define TableViewVCDelegate as delegate
TableViewController.m
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
[self notifyNow:[_locations objectAtIndex:indexPath.row]];
}
- (void) notifyNow:(Location *) location {
//this will call the method implemented in your other class
[self.delegate locationSelected:self object:(Location *) location];
NSLog(#"Selected: %#",[location name]);
}
MapViewController.h
//make it a delegate for TableViewVCDelegate
#interface MapViewController : UIViewController <TableViewDelegate>
MapViewController.m
- (void)viewDidLoad {
_tableViewController = [[TableViewController alloc]init];
_tableViewController.delegate = self; //set its delegate to self somewhere
}
!!_ This Method Doesn't Get Triggered _!!
- (void)locationSelected:(TableViewController *)sender object:(Location *)location {
NSLog(#"%# is great!", [location name]);
}
MainViewController.m (Master/Root View Controller)
#import "MainViewController.h"
#import "MapViewController.h"
#import "TableViewController.h"
#interface MainViewController ()
#property (strong, nonatomic) IBOutlet UIView *topCont;
#property (strong, nonatomic) IBOutlet UIView *bottomCont;
#property (strong, nonatomic) IBOutlet UIView *safeArea;
#end
#implementation MainViewController
MapViewController *mapViewVC;
TableViewController *tableViewVC;
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
[self.navigationController setNavigationBarHidden:YES animated:YES];
tableViewVC = [self.storyboard instantiateViewControllerWithIdentifier:#"TableViewController"];
mapViewVC = [self.storyboard instantiateViewControllerWithIdentifier:#"TopChildVC"];
[self addChildViewController:tableViewVC];
[tableViewVC.view setFrame:CGRectMake(0.0f,
0.0f,
self.safeArea.frame.size.width,
self.safeArea.frame.size.height/2)];
[self.bottomCont addSubview:tableViewVC.view];
[tableViewVC didMoveToParentViewController:self];
[self addChildViewController:mapViewVC];
[mapViewVC.view setFrame:CGRectMake(0.0f,
0.0f,
self.safeArea.frame.size.width,
self.safeArea.frame.size.height/2)];
[self.topCont addSubview:mapViewVC.view];
[mapViewVC didMoveToParentViewController:self];
}
#end
I have a containerView into my viewController. My viewController has a UISegmentedControl.
How can I send this selectedSegmentIndex selected at this moment and everytime when I change this?
I', trying with a property in the next class with prepareForSegue but this only send on first load..
Thanks!
Then Edit I'm getting: -[ViewController containerViewDidChangeSegmentIndex:]: unrecognized selector sent to instance 0x7f8db16286d0
FirstViewController (This contains A select and a containerView)
ViewController.h
#interface ViewController : UIViewController
#property (weak, nonatomic) IBOutlet UISegmentedControl *select;
#property (weak, nonatomic) IBOutlet UIView *container;
#property(nonatomic, assign) ContainerViewController * classLevelReference;
#end
ViewController.m
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[_select addTarget:self action:#selector(segmentChanged:) forControlEvents:UIControlEventValueChanged];
}
- (void)segmentChanged:(UISegmentedControl *)segment{
//since you've reference to your container view here, you can directly call its method here:
[self.classLevelReference containerViewDidChangeSegmentIndex:segment.selectedSegmentIndex];
}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
//don't forget to check the segue id, if you've multiple segues
ContainerViewController *containerView = [segue destinationViewController];
self.classLevelReference = self;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
ContainerViewController.h
#interface ContainerViewController : UIViewController
- (void)containerViewDidChangeSegmentIndex:(NSInteger)updatedIndex;
#end
ContainerView.m
#implementation ContainerViewController
- (void)containerViewDidChangeSegmentIndex:(NSInteger)updatedIndex{
//Do whatever you want with your updated index
NSLog(#"changing");
}
#end
You might want to make a method in your ContainerViewController.h like this:
#interface ContainerViewController:UIViewController
//.....other implementation here.
- (void)containerViewDidChangeSegmentIndex:(NSInteger)updatedIndex;
#end
Now implement this method in your ContainerViewController.m like this:
- (void)containerViewDidChangeSegmentIndex:(NSInteger)updatedIndex{
//Do whatever you want with your updated index
}
Now in your prepare for segue, save the reference to your ContainerViewController in a class-level variable :
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
//don't forget to check the segue id, if you've multiple segues
ContainerViewController *containerView = [segue destinationViewController];
self.classLevelReference = containerView;
}
Lastly in the FirstViewController.m, tell the container view when segment index changes.
- (void)viewDidLoad{
//.....your other implementation here.....
//add a listener to your segment's value changed action
[youregements addTarget:self action:#selector(segmentChanged:) forControlEvents:UIControlEventValueChanged];
}
- (void)segmentChanged:(UISegmentedControl *)segment{
//since you've reference to your container view here, you can directly call its method here:
[self.classLevelReference containerViewDidChangeSegmentIndex:segment.selectedSegmentIndex];
}
Important: you might've different names for the ContainerViewController and FirstViewController in your case, just apply the changes carefully.
Happy coding!
CONFIGURATION:
-UIviewController embedded in Navigationcontroller.
-UIviewController has a UIscrollview as subview
-UIscrollview has some views where charts are created: each view containing a chart has its own .h and .m file and from this file I want trigger a segue to a tableview controller.
-A Tableviewcontroller was added in xcode and a segue from the UIviewController to the TableViewcontroller was created as well (Xcode)
-created a protocol in the UIView to have the segue pushed from there.
PROBLEM:
delegate always nil, segue method will never be called
UIVIEW .h file
#protocol UItoUIvcDelegate <NSObject>
-(void)triggerSegue;
#end
#interface CFfirstGraph : UIView <CPTPlotDataSource , CPTPieChartDelegate,UIActionSheetDelegate>
#property(weak, nonatomic) id <UItoUIvcDelegate> delegate;
#end
UIVIEW .m file (snippet)
-(void)pieChart:(CPTPieChart *)pieChart sliceWasSelectedAtRecordIndex:(NSUInteger)index
{
if (self.delegate == nil)
{
NSLog(#"nil");
}
[self.delegate triggerSegue];
}
UIVIEWCONTROLLER .h file
#import "CFfirstGraph.h"
#interface CFMainViewController : UIViewController <UItoUIvcDelegate, UITableViewDelegate, UITableViewDataSource>
#end
UIVIEWCONTROLLER .m file (snippet)
- (void)viewDidLoad
{
[super viewDidLoad];
self.scrollView.contentSize = CGSizeMake(320, 1000);
[self.view addSubview:self.scrollView];
CFfirstGraph *click =[[CFfirstGraph alloc]init];
click.delegate = self ;
}
-(void)triggerSegue
{
[self performSegueWithIdentifier:#"detailedData" sender:self];
NSLog(#"estoy aqui");
}
What am I doing wrong ? why the delegate is always nil ? I tried to add the method setDelegate but still no luck.
Thanks,
dom
Make CFfirstGraph as a strong property.
#property (strong, nonatomic) CFfirstGraph * click;
- (void)viewDidLoad
{
[super viewDidLoad];
self.click =[[CFfirstGraph alloc]init];
self.click.delegate = self ;
self.scrollView.contentSize = CGSizeMake(320, 1000);
[self.view addSubview:self.scrollView];
}
ok, after many hours of sweat I found the issue.
First...delegate = nil was not the main problem.
The real issue was the protocol method triggering the segue was never called.
If i create and initialize a CFfirstGraph object (or even property) it won't be related to the view created already in x-code, and this is the main issue.
On the other hand...if I "CTRL-drag" an outlet from the UIview to the CFMainViewController i will have a property that is exactly the one i need:
#interface CFMainViewController () <UIScrollViewDelegate>
#property (weak, nonatomic) IBOutlet CFfirstGraph *FirstGraph;
Then i assign the delegate to self (CFMainViewController) in the viewDidLoad:
- (void)viewDidLoad
{
[super viewDidLoad];
self.FirstGraph.delegate = self ;
}
and the delegate method "triggerSegue" will be executed being called from the UIVIEW.
Best Regards,
dom
I did my research but haven't found an answer to the following problem: I have a custom delegate –subclass of UIView– and for some reason touchesBegan isn't working in the delegate implementation.
TestView.h
#import <UIKit/UIKit.h>
#class TestView;
#protocol TestViewDelegate <NSObject>
#end
#interface TestView : UIView
#property (assign) id <TestViewDelegate> delegate;
#end
TestView.m
#import "TestView.h"
#implementation TestView
#synthesize delegate = _delegate;
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"Touch detected on TestViewDelegate");
}
#end
ViewController.h
#import <UIKit/UIKit.h>
#import "TestView.h"
#interface ViewController : UIViewController<TestViewDelegate>
#end
ViewController.m
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
UILabel* title = [[UILabel alloc] initWithFrame:CGRectMake(20, 30, 280, 40)];
[title setFont:[UIFont fontWithName:#"Helvetica-Bold" size:30]];
[title setTextColor:[UIColor blackColor]];
[title setTextAlignment:UITextAlignmentCenter];
[title setBackgroundColor:[UIColor clearColor]];
[tile setText:#"Test"];
[self.view addSubview:title];
}
- (void)viewDidUnload
{
[super viewDidUnload];
}
#end
What am I missing to make sure touchesBegan from TestView.m gets called when touches occur in ViewController.m?
Your last line indicates a fundamental misunderstanding of views and view controllers. Touches don't occur in view controllers; touches occur in views. After a view is touched, it tells its controller that it was touched, and the controller does something with this information. The way that it does this is through a pattern called delegation.
So let's go through this piece by piece. In order to get what you want, you would have to do the following:
First: create an instance of TestView and add it as a subview of the view controller's view.
Now the view exists, and when you tap it you will see your "Touch detected on TestViewDelegate" logged to the console. But it won't actually do anything with the delegate (there isn't even a delegate yet!).
Second: set the newly created TestView's delegate property to the view controller. Do this after you create the TestView instance but before you add it to the view hierarchy.
Now they're hooked up a little, but the view is never talking to its delegate (this doesn't happen automatically; when you create a delegate protocol you have to specify what messages the view will be able to send it).
Third: add a method to the TestViewDelegate protocol and implement that method in the view controller. This could be something like touchesBeganOnTestView:(TestView *)sender, or whatever else you want the view to tell the delegate when it's touched. That looks like this:
#class TestView;
#protocol TestViewDelegate <NSObject>
- (void)touchesBeganOnTestView:(TestView *)sender;
#end
You have to add the #class line because the protocol declaration comes before the declaration of TestView -- at that point in the file, the compiler doesn't know what "TestView" means, so to avoid a warning you say "don't worry, I'm going to declare this later."
Fourth: invoke that method from TestView's touchesBegan. This is as simple as adding the line [self.delegate touchesBeganOnTestView:self];.
That'll get you what you want. From your question I'm gathering that you're pretty new to iOS/Objective-C, and it's going to be difficult if you don't have a solid understanding of the fundamentals. A good place to start might be Apple's description of delegation.
I have a UINavigationController and I would like the view of every view controller that is popped onto the stack to have a common padding/margin (e.g. 25 pixels on all sides). What is the best way to accomplish this?
I originally thought that I could implement UINavigationControllerDelegate and inside the navigationController:didShowViewController:animated or navigationController:willShowViewController:animated methods, simply change the frame of the view controller that was about to be displayed. This does not seem to have an effect though.
I tried to do the same thing inside the view controller's viewDidAppear and viewWillAppear methods, but this also did not work. Ideally, I don't want to put any logic in the controllers anyway, as they may not always be used inside a navigation controller.
One last idea that I haven't tried yet is to create a "wrapper" UIViewController that would actually get pushed onto this stack. This wrapper would add the real view controller's view as a subview with a frame that would provide the desired margin. The downside here is that I would need to subclass UINavigationController and override pushViewController:animated, where the wrapper would be initialized and pushed. Apple's documentation indicates that UINavigationController is not meant to be subclassed.
Thanks in advance.
I solved this by putting a "wrapper" UIView around the UIViewController's view instead of the UIViewController itself. The wrapper view then pads the subview by setting the subview's frame in the layoutSubviews method.
I've attached the code I used for convenience. To use, replace your UINavigationController with the PaddedNavigationController, and set the PaddedNavigationController's insets property.
PaddedNavigationController.h:
#import <Foundation/Foundation.h>
#interface PaddedNavigationController : UINavigationController
{
UIEdgeInsets _insets;
}
#property (nonatomic, assign) UIEdgeInsets insets;
#end
PaddedNavigationController.m:
#import "PaddedNavigationController.h"
#interface PaddedView : UIView
{
UIView *_view;
UIEdgeInsets _insets;
}
#property (nonatomic, assign) UIEdgeInsets insets;
+ (PaddedView *) wrapView:(UIView *)view withInsets:(UIEdgeInsets)insets;
- (id) initWithView:(UIView *)view insets:(UIEdgeInsets)insets;
#end
#implementation PaddedNavigationController
#synthesize insets = _insets;
- (void) pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
//check if the UIViewController's view has already been wrapped by the PaddedView; don't want to wrap it twice
if(![viewController.view isKindOfClass:[PaddedView class]])
{
viewController.view = [PaddedView wrapView:viewController.view withInsets:self.insets];
}
[super pushViewController:viewController animated:animated];
}
- (void) setInsets:(UIEdgeInsets)insets
{
_insets = insets;
//loop through this navigation controller's view controllers and set the new insets on any PaddedViews
for(UIViewController *viewController in self.viewControllers)
{
if([viewController.view isKindOfClass:[PaddedView class]])
{
PaddedView *padded = (PaddedView *)viewController.view;
padded.insets = insets;
}
}
}
#end
#implementation PaddedView
#synthesize insets = _insets;
+ (PaddedView *) wrapView:(UIView *)view withInsets:(UIEdgeInsets)insets
{
return [[[PaddedView alloc] initWithView:view insets:insets] autorelease];
}
- (id) initWithView:(UIView *)view insets:(UIEdgeInsets)insets
{
if(self = [super initWithFrame:view.frame])
{
_insets = insets;
self.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
_view = [view retain];
[self addSubview:view];
}
return self;
}
- (void) dealloc
{
[_view release];
[super dealloc];
}
- (void) layoutSubviews
{
//apply the insets to the subview
_view.frame = CGRectMake(self.insets.left, self.insets.top, self.frame.size.width - self.insets.left - self.insets.right, self.frame.size.height - self.insets.top - self.insets.bottom);
}
- (void) setInsets:(UIEdgeInsets)insets
{
_insets = insets;
//we need to re-layout the subviews as the insets have changed
[self layoutSubviews];
}
#end