I want to make a library that I can reuse over and over to speed up my development, add to new projects if I wish. Basically I want to build an abstraction layer. Can someone show me how I would do that and why this this portion of code:
if ([self.delegate respondsToSelector:#selector(enableCamera)]) {
BOOL enabled;
enabled = [self.delegate enableCamera];
if (enabled == YES) {
[self enableCameraMethod];
}
does not get called?
HERES MY CODE BELOW:
library.h:
#protocol usesCamera <NSObject>
#optional
-(BOOL)enableCamera;
#end
#interface Library : NSObject
#property (nonatomic, weak) id <usesCamera> delegate;
-(void)enableCameraMethod;
#end
library.m
#import "Library.h"
#implementation Library
- (id) init
{
if (self = [super init]) {
if ([self.delegate respondsToSelector:#selector(enableCamera)]) {
BOOL enabled;
enabled = [self.delegate enableCamera];
if (enabled == YES) {
[self enableCameraMethod];
}
}
return (self);
}
}
-(void)enableCameraMethod {
NSLog(#"Implement my camera method here");
}
#end
UIViewController.h
#import <UIKit/UIKit.h>
#import "Library.h"
#interface ViewController : UIViewController <usesCamera>
#end
UIViewController.m
#import "ViewController.h"
#import "Library.h"
#interface ViewController ()
#property (nonatomic, strong) UIViewController *myVC;
#end
#implementation ViewController
-(BOOL)enableCamera {
return YES;
}
- (void)viewDidLoad
{
[super viewDidLoad];
Library *myLibrary = [[Library alloc] init];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
did you set your delegate for myLibrary instance in your ViewController class.
you have to do something like this:
Library *myLibrary = [[Library alloc] init];
myLibrary.delegate = self;
As init is called before setting the delegate, so it might not worked, instead of defining the logic in init function create another method and call this method after setting the delegate.
Related
I do not understand because the error appears "Method in protocol not implemented"
myProtocol.h
#import <Foundation/Foundation.h>
#protocol myProtocol <NSObject>
-(UIImage *)transferImage;
#end
ViewController.h
#import "SecondClass.h"
#interface ViewController : UIViewController<myProtocol, UINavigationControllerDelegate>
{
UIView *view;
}
#property (nonatomic,retain) UIImageView *imageView;
- (IBAction)sendImage:(id)sender;
#end
ViewController.m
#import "ViewController.h"
#import "SecondViewController.h"
#import "myProtocol.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
_imageView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:#"VoodooVibe#2x.png"]];
[view addSubview:_imageView];
NSLog(#"I am in VC.m");
}
-(UIImage *)transferImage{
NSLog(#"I am in transferImage");
return _imageView.image;}
- (IBAction)sendImage:(id)sender {
SecondViewController *secClass = [[SecondViewController alloc]init];
secClass.delegate=self;[secClass callTransfer];NSLog(#"I am in sender");[self.navigationController pushViewController:secClass animated:YES];}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
SecondViewController.h
#import <UIKit/UIKit.h>
#import "myProtocol.h"
#import "ViewController.h"
#interface SecondViewController : UIViewController<myProtocol,UINavigationControllerDelegate> {
UIView *secondView;
IBOutlet UIImageView *myImage;
id <myProtocol> myDelegate;
}
#property (nonatomic,strong) UIImageView *myImage;
#property(nonatomic,weak) id delegate;
-(void)callTransfer;
#end
SecondViewController.m
#import "SecondViewController.h"
#import "ViewController.h"
#import "myProtocol.h"
#interface SecondViewController ()
#end
#implementation SecondViewController
#synthesize delegate,myImage;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
[secondView addSubview:myImage];
}
-(void)callTransfer
{
myImage.image=[delegate performSelector:#selector(transferImage)];
myImage.image=[UIImage imageNamed:#"VoodooVibe#2x.png"];
NSLog(#"%#",myImage.image);
NSLog(#"I am in call transfer");
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
You call the delegate method inside the SecondViewController but you didn't insert it. If you get a warning like ... not implemented it just says, you forgot to include a method.
You could insert the method like this
-(UIImage *)transferImage{
//do something here if delegate has been called
}
or you just add a parameter above the method inside your delegate block:
#optional
if you don't specify it, all methods will be set to #required initial.
it is as simple as you have declared a method in your protocol implementation but have not implemented the same. In your Second VC you have not implemented the method "tranfer image" . So the compiler is generating a warning
I started testing ECSlidingViewController and after I tried to access FirstTopViewController I have a big trouble - because in FirstToViewController I already have ZBarReaderDelegate implemented and all examples of delegate are not triggering any method from my delegate.
Basically I have this stuff:
FirstTopViewController.h
#import ...MyStuff...
#import "UnderRightViewController.h"
#interface FirstTopViewController : UIViewController <RightViewDelegate, ZBarReaderDelegate>
#property (weak, nonatomic) IBOutlet UITextView *labelTotal;
#end
FirstTopViewController.m
#import "FirstTopViewController.h"
#implementation FirstTopViewController
- (void)setTotalViewController:(UnderRightViewController*)controller didTotalChange:(NSString*)total
{
//labelTotal.text = total;
NSLog(#"I'm here!!! and received %#", total);
}
From other side I have
UnderRightViewController.h
#import <UIKit/UIKit.h>
#import "ECSlidingViewController.h"
#class UnderRightViewController;
#protocol RightViewDelegate <NSObject>
- (void)setTotalViewController:(UnderRightViewController*)controller didTotalChange:(NSString*)total;
#end
#interface UnderRightViewController : UITableViewController
#property (nonatomic, weak) id <RightViewDelegate> delegate;
#end
UnderRightViewController.m
#import "UnderRightViewController.h"
#interface UnderRightViewController ()
#end
#implementation UnderRightViewController
#synthesize delegate;
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
[delegate setTotalViewController:self didTotalChange:#"foo"];
}
#end
I'm trying this entire day solve this puzzle but I never get setTotalViewController fired.
Thanks in advance.
Friend you did a small mistake, when you navigate from FirstTopViewController to UnderRightViewController at that time you need to do this in FirstTopViewController.m:-
UnderRightViewController *obj = [[UnderRightViewController
alloc] initWithNibName:#"UnderRightViewController" bundle:nil];
obj.delegate = self; // u forget to assign protocol handler
[self.navigationController pushViewController:obj animated:YES];
[obj release];
You don't have any code that is setting the delegate for the UnderRightViewController. I don't know what object owns both of these controllers, but before either UnderRightViewController and FirstTopViewController are displayed it should run code something like this:
FirstTopViewController *ftvc = //... where ever you get a reference to this from
UnderRightViewController *urvc = ...;
urvc.delegate = ftvc;
In your above code you are using custom delegates and also you have used it for sending message to onecontroller class to another controller class. So below is the same sample code of custom delegates, it is working fine in similar way you have to implement and also the problem in your code is you are not setting the delegate, so please follow below how to set the same and call the method. here i have used your same method only return type i have defined as NSString in-spite of void for explaining purpose, but you can use void according to your requirement hope it will be helpful to you:-
First Controller Class AWindowController.h
#interface AWindowController : NSWindowController<sampleDelegate>
{
NSString *textA;
}
#property(readwrite,retain)NSString *textA;
-(IBAction)doSet:(id)sender;
#end
#import "AWindowController.h"
#import "BWindowController.h"
#interface AWindowController ()
#end
#implementation AWindowController
#synthesize textA;
- (id)initWithWindow:(NSWindow *)window
{
self = [super initWithWindow:window];
if (self) {
// Initialization code here.
}
return self;
}
- (NSString *)setTotalViewController:(BWindowController*)controller didTotalChange:(NSString*)total
{
NSLog(#"recieved");
return #"recieved";
}
- (void)windowDidLoad
{
[super windowDidLoad];
// Implement this method to handle any initialization after your window controller's window has been loaded from its nib file.
}
-(NSString*)windowNibName
{
return #"AWindowController";
}
-(IBAction)doSet:(id)sender
{
[self setTextA:#"Awindow Button Pressed"];
BWindowController *b=[[BWindowController alloc]init];
b.delegate=self;
[b showWindow:self];
}
#end
Second Controller Class BWindowController.h
#import <Cocoa/Cocoa.h>
#import "sampleDelegate.h"
#class BWindowController;
#protocol sampleDelegate <NSObject>
#required
//-(NSString *)getDataValue;
- (NSString *)setTotalViewController:(BWindowController*)controller didTotalChange:(NSString*)total;
#end
#interface BWindowController : NSWindowController<sampleDelegate>
{
NSString *bTextValue;
id<sampleDelegate>delegate;
}
#property(readwrite,retain)NSString *bTextValue;
#property(readwrite,assign)id<sampleDelegate>delegate;
#end
#import "BWindowController.h"
#interface BWindowController ()
#end
#implementation BWindowController
#synthesize bTextValue,delegate;
- (id)initWithWindow:(NSWindow *)window
{
self = [super initWithWindow:window];
if (self) {
// Initialization code here.
}
return self;
}
- (NSString *)setTotalViewController:(BWindowController*)controller didTotalChange:(NSString*)total;
{
return nil;
}
- (void)windowDidLoad
{
NSString *str= [[self delegate]setTotalViewController:self didTotalChange:#"recieved"];
self.bTextValue=str;
[super windowDidLoad];
// Implement this method to handle any initialization after your window controller's window has been loaded from its nib file.
}
-(NSString*)windowNibName
{
return #"BWindowController";
}
#end
Attached screen shot in Output:-
Below is window is the AwindowController.h class
Below in the same above window pressing the button and when Awindow button pressed data will send
and notification will be recieved in Bwindow using above define custom delegates as attached in the screen shot.
I'm working on an iPad App and i'm having issue with delegate... the protocol method does not get invoked. i'm not sure what i'm missing, here is my code.
#protocol pickerLabelProtocol <NSObject>
- (void)selectedPickerData:(UILabel *)sender;
#end
#interface showPickerVC : UIViewController
#property (nonatomic, strong) id <pickerLabelProtocol> delegate;
#end
#implementation showPickerVC
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
//i used breakpoint, the 'delegate' is always nil for some reason?
[self.delegate selectedPickerData:self.mainLabel];
}
----------------------
#interface someViewController : UIViewController <pickerLabelProtocol>
#property (nonatomic, strong) showPickerVC *showPicker;
#end
#implementation someViewController
- (void)selectedPickerData:(UILabel *)sender
{
//protocol method
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.showPicker = [[showPickerVC alloc]init];
self.showPicker.delegate = self;
}
I can not got any mistake From your code but i suggest you that Be clear about when you create object of showPickerVC add it's delegate self
Such Like ,
showPickerVC *obj = [[showPickerVC alloc] init];
obj.delegate = self; /// YOur protocol delegate
.
.
[self presentModalViewController:obj animated:YES];
And Also add code as following
#implementation showPickerVC
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
if([self.delegate respondsToSelector:#selector(selectedPickerData:)])
{
[self.delegate selectedPickerData:self.mainLabel];
}
}
For More information about How to create/use of Protocol.
Hi I have two viewControllers.
NewsViewController
#import "SingleViewController.h"
#interface NewsViewController : UIViewController {
}
- (NSString *)getFirstImage:(NSString *)htmlString;
#end
and the implementation file:
#import "SingleViewController.h"
SingleViewController *singleViewController;
#interface NewsPadViewController () <UIActionSheetDelegate>
- (void)loadSubscriptions;
#property (nonatomic, assign) BOOL wrap;
#property (nonatomic, retain) NSMutableArray *items;
#end
#implementation NewsPadViewController
....CODE....
- (void)carouselCurrentItemTapped{
//[self addSubview:articolo];
MWFeedItem *item =[reader.feedItems objectAtIndex:[carousel currentItemIndex]];
NSLog(#"Current Item tappped, index: %d", [carousel currentItemIndex]);
singleViewController.prova.text=#"CIAO";
singleViewController.ciao=#"sample";
[singleViewController.web loadHTMLString:item.summary baseURL:nil];
NSLog(#"conternutio:");
NSLog(singleViewController.ciao);
}
SingleViewController.h
#import <UIKit/UIKit.h>
#interface SingleViewController : UIViewController{
#public
UIWebView *web;
UILabel *prova;
NSString *ciao;
}
#property (nonatomic,retain) IBOutlet UIWebView *web;
#property (nonatomic,retain) IBOutlet UILabel *prova;
#property (nonatomic,retain) IBOutlet NSString *ciao;
#end
and SingleViewController.m
#import "SingleViewController.h"
#implementation SingleViewController
#synthesize web,prova,ciao;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)didReceiveMemoryWarning
{
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[prova setText:ciao];
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
#end
Why I can't access from NewsPadViewController at object in SingleViewController? Where is my error? thanks
UPADATE
- (void)carouselCurrentItemTapped{
//[self addSubview:articolo];
MWFeedItem *item =[reader.feedItems objectAtIndex:[carousel currentItemIndex]];
NSLog(#"Current Item tappped, index: %d", [carousel currentItemIndex]);
SingleViewController *singleViewController = [[SingleViewController alloc] initWithNibName:#"SingleViewController" bundle:[NSBundle mainBundle]];
singleViewController.prova.text=#"CIAO";
singleViewController.ciao=#"sample";
[singleViewController.web loadHTMLString:item.summary baseURL:nil];
NSLog(#"conternutio:");
NSLog(singleViewController.ciao);
[singleViewController setOpz:#"sample"];
}
I don't see any instantiation of SingleViewController. You have a pointer to it, but I don't see anywhere in your code example where you actually create it.
Somewhere you need something like:
if (!singleViewController) {
singleViewController = [[SingleViewController alloc] init];
}
or
SingleViewController *singleViewController = [[SingleViewController alloc] initWithNibName:#"SingleView" bundle:nil];
or from somewhere else you need to send a message or set an instance variable in NewsViewController that points to an existing instance of SingleViewController.
I'm using a library, which is a class that inherits from UIView. How do I programmatically create an UIViewController that uses this class, and not a normal UIView?
The ViewController's .h file looks as follows:
#import <UIKit/UIKit.h>
#import "PLView.h"
#interface HelloPanoramaViewController : UIViewController {
IBOutlet PLView * plView;
}
#property (nonatomic, retain) IBOutlet PLView *plView;
#end
The .m file as follows:
#import "HelloPanoramaViewController.h"
#implementation HelloPanoramaViewController
#synthesize plView;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do stuff here...
}
- (void)dealloc
{
[plView release];
[super dealloc];
}
#end
And then I should use a nib to let "plView variable pointing to the view".
But without using Interface Builder, how would I do this programmatically? How could I let this UIViewController create an PLView, instead of an UIView?
your UIViewController will something that looks like
#import "HelloPanoramaViewController.h"
#implementation HelloPanoramaViewController
- (void)loadView
{
self.view = [PLView plview]//or whatever it takes to create the plview.
}
- (void)viewDidLoad
{
//create more objects
}
- (void)viewDidUnload
{
//release unwanted objects that were created viewDidLoad
}
-(void) dealloc
{
// release all
[super dealloc];
}
#end
more info... here
In the place where you create your viewController, also create an instance of your custom view, and then set that view to your controller's view:
HelloPanoramaViewController *controller = [[HelloPanoramaViewController alloc] init];
PLView *view = [[PLView alloc] init];
controller.view = view;