I am updating some legacy objective C code to be able to be compiled under OSX 10.13. The legacy code worked and most of the update code does as well except for an NSSoundDelegate that needs to handle a didFinishPlaying function. The delegate method is not being called. The delegate method is contained in a class called MyClass. Here is relevant code.
In MyClass.h:
#class MyClass;
#protocol MyClass <NSObject>
#optional
- (void)sound:(NSSound *)sound didFinishPlaying:(BOOL)flag;
#end
#interface MyClass : NSObject <NSSoundDelegate>
{
}
#property (nonatomic, assign) id <NSSoundDelegate> delegate;
- (void)sound:(NSSound *)sound didFinishPlaying:(BOOL)flag;
- (id) init;
#end
Then in MyClass.m:
#implementation MyClass
#synthesize delegate;
- (void)sound:(NSSound *)sound didFinishPlaying:(BOOL)flag
{
if (flag) {
[[NSNotificationCenter defaultCenter] postNotificationName:#"handleNSSoundDidFinishPlaying" object:sound];
}
}
- (id)init
{
MyClass *thePointer;
self = [super init];
if (self) {
thePointer = self;
self.delegate = (id)thePointer;
isInitialized = NO;
isClosing = NO;
[self set_currentSounds:[NSMutableArray arrayWithCapacity:0]];
}
return self;
}
#end
Can anyone see what I'm missing?
I think you should notify the delegate object like:
if([_delegate respondsToSelector:#selector(sound: didFinishPlaying:)])
[_delegate sound:self didFinishPlaying:_flag];
Hope this will help you.
Found the problem! When allocating the sound to be played, you have to set the sounds delegate using [theSnd setDelegate:self]; so that when the sound stops playing, the delegate gets called, in this case the delegate is in the MyClass .m file.
Related
I have a hierarchy of UIViews. They are all handled differently but if nested I can not get my setDelegate of super to fire. I receive a crash exception [ThirdClass setDelegate:] unrecognized selector sent to instance. This actually happens no matter what (subclass) i use SecondClass or ThirdClass, but If I use (FirstClass) everything works as it should but any subclassing of the delegate it does not recognize the call. I have simplified what I am doing below which if I call out my first class separately inside my MainControlInterface everything works as it should. Im sure Im doing something wrong here but can't determine what that is, If anyone could help that would be greatly appreciated, thank you.
#protocol FirstClassDataSource, FirstClassDelegate;
#interface FirstClass : UIView
#property (nonatomic, weak_delegate) __nullable id<FirstClassDataSource> dataSource;
#property (nonatomic, weak_delegate) __nullable id<FistClassDelegate> delegate;
#end
#protocol FirstClassDataSource <NSObject>
- (NSInteger)doSomething:(FirstClass *)class;
#optional
- (NSInteger)doSomethingElse:(FirstClass *)class;
#end
#protocol FirstClassDelegate <NSObject>
#optional
- (void)handleMoreDelegateMethods:(FirstClass *)class;
#end
#implementation FirstClass
- (void)setDataSource:(id< FirstClassDataSource >)dataSource
{
if (_dataSource != dataSource)
{
_dataSource = dataSource;
if (_dataSource)
{
[self reloadData];
}
}
}
- (void)setDelegate:(id< FirstClassDelegate>)delegate
{
if (_delegate != delegate)
{
_delegate = delegate;
if (_delegate && _dataSource)
{
[self setNeedsLayout];
}
}
}
#end
#interface SecondClass : FirstClass
-(id)sencondClassesPrivateMethods;
#end
#interface ThirdClass : secondClass
-(id)thirdClassPrivateMethods;
#end
#interface MainControlInterface : UIView <FirstClassDataSource, FirstClassDelegate>
-(ThirdClass *)thirdClass;
#end
#implementation MainControlInterface
-(void)didMoveToSuperview{
ThirdClass *mythirdSubClass = [self thirdClass];
mythirdSubClass.delegate = self;
mythirdSubClass.dataSource = self;
}
#end
I can't tell what you're doing wrong either. But, your sample code will not compile. (It's full of typos.) I have tried to recreate what you're talking about, simplifying it further. (I've used CodeRunner, a macOS app which facilitates this sort of thing.)
#import <Foundation/Foundation.h>
#protocol FirstClassHandling <NSObject>
- (void)doTheThing;
#end
#interface FirstClass : NSObject
#property (nonatomic, weak) id<FirstClassHandling> delegate;
- (void)doSomething;
#end
#implementation FirstClass
- (void)doSomething
{
NSLog(#"First class.");
if ([[self delegate] respondsToSelector:#selector(doTheThing)]) {
[[self delegate] doTheThing];
}
}
#end
#interface SecondClass : FirstClass
#end
#implementation SecondClass
- (void)doSomething
{
NSLog(#"Second class");
[super doSomething];
}
#end
#interface Handler : NSObject <FirstClassHandling>
#end
#implementation Handler
- (void)doTheThing
{
NSLog(#"Doing my thing!!!");
}
#end
int main(int argc, char *argv[])
{
#autoreleasepool {
Handler* handler = [[Handler alloc] init];
SecondClass* sc = [[SecondClass alloc] init];
sc.delegate = handler;
[sc doSomething];
}
}
The above does not crash. Please fix your example code.
I want to provide methods used in several view controllers called in my delegate methods.
For example, I have some CloudKit functionality (I've added this to my own framework, but I don't think thats important), where I want to provide some crash logging.
Previosuly I had a crashLog function in each of my view controllers, which worked fine, but I have a lot of duplicate code.
Therefore I'd like to produce a category with these methods instead.
However I'm having difficulty getting my delegate methods to see these category methods.
Here's my code..
UIViewController+CloudKitDelegates.h
#interface UIViewController (CloudKitDelegates) <iCloudDBDelegate>
#property (weak,nonatomic) id<iCloudDBDelegate>iCloudDBDelegate;
-(void)crashLog:(NSString*)message, ...;
#end
UIViewController+CloudKitDelegates.m
#import "UIViewController+CloudKitDelegates.h"
#implementation UIViewController (CloudKitDelegates)
#dynamic iCloudDBDelegate;
-(void)crashLog:(NSString*)message, ...
{
va_list args;
va_start(args, message);
NSLog(#"%#", [[NSString alloc] initWithFormat:message arguments:args]);
va_end(args);
}
#end
h file - my calling view controller (e.g. My View Controller)
#import "UIViewController+CloudKitDelegates.h"
m file - delegate method
-(NSString*)getDBPath
{
[self.iCloudDBDelegate crashLog: #"testing"];
From this call I'm getting an error ...
'NSInvalidArgumentException', reason: '-[MyViewController crashLog:]:
unrecognized selector sent to instance
The error is showing that my calling view controller called MyViewController doesn't have the crashLog method, which I have in my category.
Any ideas where I'm going wrong ?
The problem: identical method crashLog: in multiple classes, for example
#interface ViewController : UIViewController
#end
#implementation ViewController
- (void)someMethod {
[self crashLog:#"error"];
}
-(void)crashLog:(NSString *)message {
NSLog(#"%#", message);
}
#end
Solution A: move crashLog: to a common superclass (or a category on superclass UIViewController)
#interface CommonViewController : UIViewController
-(void)crashLog:(NSString *)message;
#end
#implementation CommonViewController
-(void)crashLog:(NSString *)message {
NSLog(#"%#", message);
}
#end
#interface ViewController : CommonViewController
#end
#implementation ViewController
- (void)someMethod {
[self crashLog:#"error"];
}
#end
Solution B: move crashLog: to a delegate and protocol
#protocol ICloudDBDelegate
-(void)crashLog:(NSString *)message;
#end
#interface DelegateClass : AnyClass <ICloudDBDelegate>
#end
#implementation DelegateClass
-(void)crashLog:(NSString *)message {
NSLog(#"%#", message);
}
#end
#interface ViewController : UIViewController
#end
#implementation ViewController
#property (weak, nonatomic) id <ICloudDBDelegate> iCloudDBDelegate;
- (void)viewDidLoad
{
[super viewDidLoad];
AppDelegate *appDel = (AppDelegate *)[[UIApplication sharedApplication] delegate];
self.iCloudDBDelegate = appDel.iCloudDBDelegate;
}
- (void)someMethod {
[self.iCloudDBDelegate crashLog:#"error"];
}
#end
#interface AppDelegate : UIResponder <UIApplicationDelegate, AppDelProtocolDelegate, iCloudDBDelegate>
#property (strong, nonatomic) id<iCloudDBDelegate>iCloudDBDelegate;
#end
#implementation AppDelegate
- (id<iCloudDBDelegate>)iCloudDBDelegate {
if (!_iCloudDBDelegate) {
_iCloudDBDelegate = [[DelegateClass alloc] init];
}
return _iCloudDBDelegate;
}
#end
Now we have new problem: property iCloudDBDelegate in multiple classes
Solution B + A: move crashLog to a delegate, move iCloudDBDelegate property to a superclass
#protocol ICloudDBDelegate
-(void)crashLog:(NSString *)message;
#end
#interface DelegateClass : AnyClass <ICloudDBDelegate>
#end
#implementation DelegateClass
-(void)crashLog:(NSString *)message {
NSLog(#"%#", message);
}
#end
#interface CommonViewController : UIViewController
#property (weak, nonatomic) id <ICloudDBDelegate> iCloudDBDelegate;
#end
#implementation CommonViewController
#end
#interface ViewController : CommonViewController
#end
#implementation ViewController
- (void)someMethod {
[self.iCloudDBDelegate crashLog:#"error"];
}
#end
Solution C:
Another approach is a singleton object like NSUserDefaults.standardUserDefaults or NSFontManager.sharedFontManager: CloudDBManager.sharedCloudDBManager. No category or protocol required, just include CloudDBManager.h and use CloudDBManager.sharedCloudDBManager from everywhere.
#interface CloudDBManager : NSObject
#property(class, readonly, strong) CloudDBManager *sharedCloudDBManager;
-(void)crashLog:(NSString *)message;
#end
#implementation CloudDBManager
+ (CloudDBManager *)sharedCloudDBManager {
static CloudDBManager *sharedInstance = nil;
static dispatch_once_t onceToken = 0;
dispatch_once(&onceToken, ^{
sharedInstance = [[CloudDBManager alloc] init];
// Do any other initialisation stuff here
});
return sharedInstance;
}
-(void)crashLog:(NSString *)message {
NSLog(#"%#", message);
}
#end
#interface ViewController : CommonViewController
#end
#implementation ViewController
- (void)someMethod {
[CloudDBManager.sharedCloudDBManager crashLog:#"error"];
}
#end
(I've added this to my own framework, but I don't think thats important)
Yep, that's the typical problem. You've failed to include -ObjC in the link flags.
See Building Objective-C static libraries with categories. This applies to frameworks as well.
ObjC does not create linker symbols for methods. It can't, they're not resolved until runtime. So the category methods aren't seen by the linker as "missing" and it doesn't bother linking the relevant compile unit. This is an important optimization that keeps you from linking all of a massive C library just because you use one function in it, but Objective-C categories break some of the linker's assumptions. The compiler saw the definition (via the header), but the linker didn't care, so there's no error until runtime.
The -ObjC flag says "this C-looking compile unit is actually Objective-C; link all of it even if you don't think you need to."
I have a class in which response from server is coming as responseDictionary.I want to use this responseDictionary in another VC but not able to send the dictionary through delegates.Kindly explain with code in objective c that how this can be achieved.
sample project, it is simply for demo, u can refer it
first we will create a class names WebService it will request the data, and as a response it will get a dictionary, and also it defines a delegate to notify that data is received and sent to the VC (in your case)
in WebService.h
#import <Foundation/Foundation.h>
#protocol WebServiceDelegate;
#interface WebService : NSObject
{
}
#property(nonatomic, assign) id<WebServiceDelegate>webServiceDelegate;
- (void)webserviceRequestData; //initiates the data request
#end
#protocol WebServiceDelegate <NSObject>
- (void)webService:(WebService *)aWebService didReceievResponseData:(NSDictionary *)dataDictionary;
#end
in WebService.m
#import "WebService.h"
#implementation WebService
- (instancetype)init
{
self = [super init];
if(self)
{
}
return self;
}
- (void)webserviceRequestData
{
sleep(5); //for demo
[self makeWebserviceToGetSomeData];
}
- (void)makeWebserviceToGetSomeData
{
NSDictionary *data = [NSDictionary dictionaryWithObjectsAndKeys:#"Data_1",#"Key_1",#"Data_2",#"Key_2",#"Data_3",#"Key_3", nil];
[self receievedSomeData:data];
}
//finally data is received as dictionary and send it to VC
- (void)receievedSomeData:(NSDictionary *)dataDictionary
{
if([self.webServiceDelegate respondsToSelector:#selector(webService:didReceievResponseData:)])
[self.webServiceDelegate webService:self didReceievResponseData:dataDictionary];
}
#end
and in the view controller class ViewController.h
#import <UIKit/UIKit.h>
#import "WebService.h"
#interface ViewController : UIViewController<WebServiceDelegate>
#property(nonatomic, strong) WebService *myWebService;
#end
and in ViewController.m
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
_myWebService = [[WebService alloc] init];
_myWebService.webServiceDelegate = self; //this is call back to this class
}
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
[_myWebService webserviceRequestData];
}
- (void)webService:(WebService *)aWebService didReceievResponseData:(NSDictionary *)dataDictionary
{
NSLog(#"web data:%#",dataDictionary.description);
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
after 5 seconds we made to call the method makeWebserviceToGetSomeData and it will send the call the another method receievedSomeData: method in this we are checking weather caller implemented the method or not to avoid crash(unrecognised selector sent to object), and we are passing the data (dictionary) to view controller
and also u can call web service from any class (any viewcontroller) and set it as a delegate
I have a strange problem in my Cocoa-app. I have a main window with an NSTableView in it with a controller class (PropValTableHandler). I have made the connections between my NSTableView and the PropValTableHandler, but when the 'numberOfRowsInTableView' method is called it looks like not the 'PropValTableHandler' initialized in 'AddDelegate' is used, since the 'propMan' field is not initialized (it is like the normal init is used, so it has to be another instance of this class).
Am I doing something wrong? I have another NSTableView handler in another window, that works, but it does not have a custom init method.
Source codes:
AppDelegate
#import "AppDelegate.h"
#implementation AppDelegate
#synthesize propValTableController = _propValTableController;
-(id) init
{
self = [super init];
if (self)
{
_propMan = [[OCPropertyManager alloc]initWithPath:"./data/"];
_propValTableController = [[PropValTableHandler alloc]
[initWithPropManager:_propMan];
}
return self;
}
PropValTableHandler
#interface PropValTableHandler : NSObject <NSTableViewDataSource>
#property IBOutlet NSTableView * constants;
#property OCPropertyManager * propMan;
-(id) initWithPropManager:(OCPropertyManager*)pm;
-(NSInteger) numberOfRowsInTableView:(NSTableView *)tableView;
#end
#import "PropValTableHandler.h"
#implementation PropValTableHandler
-(id) initWithPropManager:(OCPropertyManager*)pm
{
self = [super self];
if (self)
{
self.propMan = pm;
}
return self;
}
/*********** TABLEVIEW DATASOURCE ******************/
-(NSInteger) numberOfRowsInTableView:(NSTableView *)tableView
{
NSInteger count = [_propMan.consts count];
return count;
}
/**************************************************/
#end
I have solved the problem by adding a
#property IBOutlet AppDelegate *parent;
for the PropValTableHandler class and making the connections.
This way I can use:
parent.propMan
where ever I need it without passing a reference to it in the init method.
I have some very small classes that I feel should be "pulled up" but the methods are so small I'm not sure. For example, the only thing that's meaningfully different is the body of the buildFromJSON: selector.
I acknowledge that this is similar to:
Pull-up refactoring, Objective-C
but I feel my question is specific to refactoring very small classes/methods.
Also, not sure it relates to my particular code example, but I'm wondering if a child class says it conforms to a protocol, whether it's enough that it's parent actually supply the implementation of required selector(s)?
#implementation AsyncFoo
-(void)dealloc {
[clientDelegate release];
[super dealloc];
}
- (id)initWithDelegate: (id <ServiceClientProtocol>) delegate {
if((self = [super init])) {
clientDelegate = [delegate retain];
}
return self;
}
- (void)buildFromJSON:(NSString*)jsonResponseString {
[clientDelegate serviceComplete:[RestAdapter buildFooArray: jsonResponseString]];
}
#end
#implementation AsyncBar
-(void)dealloc {
[clientDelegate release];
[super dealloc];
}
- (id)initWithDelegate: (id <ServiceClientProtocol>) delegate {
if((self = [super init])) {
clientDelegate = [delegate retain];
}
return self;
}
- (void)buildFromJSON:(NSString*)jsonResponseString {
[clientDelegate serviceComplete:[RestAdapter buildBarArray:jsonResponseString]];
}
#end
Answers including code example would be great.
EDIT: Post accepted answer I'd like to add that since I was able to subclass, the derived classes did not need to declare that they conformed to protocol:
#interface Async : NSObject <ModelBuilderProtocol> {
id <ServiceClientProtocol> clientDelegate;
}
- (void)buildFromJSON:(NSString*)jsonResponseString;
#end
#interface AsyncArtistById : Async
#end
You don't normally retain your delegates as this can cause a retain cycle.
Knowing what I know from looking at your example I would probably implement like this:
The super class
// Async.h
#interface Async : NSObject
#property (nonatomic, assign) id<ServiceClientProtocol> delegate;
- (void)buildFromJSON:(NSString *)jsonResponseString;
#end
// Async.m
#implementation Async
#synthesize delegate = _delegate;
- (id)initWithDelegate:(id<ServiceClientProtocol>)delegate
{
self = [super init];
if(self) {
_delegate = delegate;
}
return self;
}
- (void)buildFromJSON:(NSString *)jsonResponseString
{
// This will ensure that we over ride this method in a sub class
[NSException raise:NSInternalInconsistencyException
format:#"You must override %# in a subclass", NSStringFromSelector(_cmd)];
}
#end
Concrete subclass AsyncFoo
// AsyncFoo.h
#interface AsyncFoo : Async
#end
// AsyncFoo.m
#implementation AsyncFoo
- (void)buildFromJSON:(NSString *)jsonResponseString
{
[self.delegate serviceComplete:[RestAdapter buildFooArray: jsonResponseString]];
}
#end
Concrete subclass AsyncBar
// AsyncBar.h
#interface AsyncBar : Async
#end
// AsyncBar.m
#implementation AsyncBar
- (void)buildFromJSON:(NSString *)jsonResponseString {
[self.delegate serviceComplete:[RestAdapter buildBarArray:jsonResponseString]];
}
#end