NSInvocation setTarget example ios

setTarget:

Sets the receiver’s target.

- (void)setTarget:(id)anObject

Parameters

anObject

The object to assign to the receiver as target. The target is the receiver of the message sent by invoke.

( NSInvocation setTarget example )

- (void)hello:(NSString *)hello world:(NSString *)world
{
    NSLog(@"%@ %@!", hello, world);

    NSMethodSignature *signature  = [self methodSignatureForSelector:_cmd];
    NSInvocation      *invocation = [NSInvocation invocationWithMethodSignature:signature];

    [invocation setTarget:self];                    // index 0 (hidden)
    [invocation setSelector:_cmd];                  // index 1 (hidden)
    [invocation setArgument:&hello atIndex:2];      // index 2
    [invocation setArgument:&world atIndex:3];      // index 3

    // NSTimer's always retain invocation arguments due to their firing delay. Release will occur when the timer invalidates itself.
    [NSTimer scheduledTimerWithTimeInterval:1 invocation:invocation repeats:NO];
}

( NSInvocation setTarget example )

- (void)log {
    NSLog(@"-[Vehicle log] invoked on an instance of %@", NSStringFromClass([self class]));
}

- (void)runVehiclesLog {
    [super log];
}

- (void)runInvocationThatTargetsVehicle {
    SEL selector = @selector(runVehiclesLog);
    NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:[self methodSignatureForSelector:selector]];
    [invocation setTarget:self];
    [invocation setSelector:selector];
    [invocation invoke];
}

( NSInvocation setTarget example )

int main() {
    NSAutoreleasePool *pool = [NSAutoreleasePool new];            
    Person *person = [Person new];

    SEL sel = @selector(setName:age:);

    NSMethodSignature *sig = [Person instanceMethodSignatureForSelector:sel];
    NSInvocation *inv = [NSInvocation invocationWithMethodSignature:sig];

    [inv setTarget:person];
    [inv setSelector:sel];

    NSString *name = nil;
    NSNumber *age = nil;

    [inv setArgument:&name atIndex:2];
    [inv setArgument:&age atIndex:3];

    // [inv retainArguments];
    // [inv invoke];

    NSInvocationOperation *op = [[[NSInvocationOperation alloc] initWithInvocation:inv] autorelease];
    NSOperationQueue *queue = [NSOperationQueue new];
    [queue addOperation:op];

    [pool release];
    return 0;
}

NSInvocation setSelector example ios

setSelector:

Sets the receiver’s selector.

- (void)setSelector:(SEL)selector

Parameters

selector

The selector to assign to the receiver.

( NSInvocation setSelector example )

NSMethodSignature *sig = nil;
sig = [[self class] instanceMethodSignatureForSelector:@selector(viewDidAppear:)];
NSInvocation *myInvocation = nil;
myInvocation = [NSInvocation invocationWithMethodSignature:sig];

[myInvocation setTarget:_somePopoverController];
[myInvocation setSelector:@selector(dismissPopoverAnimated:)];
BOOL animate = YES;
[myInvocation setArgument:&animate atIndex:2];
[myInvocation invoke];

( NSInvocation setSelector example )

NSString * parameterSignature = @"v@:";
NSMethodSignature * signature = [NSMethodSignature signatureWithObjCTypes:[parameterSignature UTF8String]]; 
NSInvocation * invocation = [NSInvocation invocationWithMethodSignature:signature];
[invocation setSelector:@selector(aMethodWithNoParms)];

( NSInvocation setSelector example )

- (void)hello:(NSString *)hello world:(NSString *)world
{
    NSLog(@"%@ %@!", hello, world);

    NSMethodSignature *signature  = [self methodSignatureForSelector:_cmd];
    NSInvocation      *invocation = [NSInvocation invocationWithMethodSignature:signature];

    [invocation setTarget:self];                    // index 0 (hidden)
    [invocation setSelector:_cmd];                  // index 1 (hidden)
    [invocation setArgument:&hello atIndex:2];      // index 2
    [invocation setArgument:&world atIndex:3];      // index 3

    // NSTimer's always retain invocation arguments due to their firing delay. Release will occur when the timer invalidates itself.
    [NSTimer scheduledTimerWithTimeInterval:1 invocation:invocation repeats:NO];
}

NSInvocation setReturnValue example ios

setReturnValue:

Sets the receiver’s return value.

- (void)setReturnValue:(void *)buffer

Parameters

buffer

An untyped buffer whose contents are copied as the receiver's return value.

Discussion( NSInvocation setReturnValue example )

This value is normally set when you send an invoke or invokeWithTarget: message.

( NSInvocation setReturnValue example )

void (^theBlock)(NSInvocation *) = ^(NSInvocation *invocation) {
    NSString *capitalizedString = @"255";
    [invocation setReturnValue:&capitalizedString];
};

( NSInvocation setReturnValue example )

- (void)setUpReturnValue:(NSInvocation *)anInvocation
{
  if (returnValueIsFromInvocation) {
    NSInvocation *returnValueInvocation = (NSInvocation *)returnValue;
    [returnValueInvocation invoke];
    void *buffer = malloc([[anInvocation methodSignature] methodReturnLength]);
    [returnValueInvocation getValue:buffer];
    [anInvocation setReturnValue :buffer];
    free(buffer);
  }
  else if(returnValueShouldBeThrown)
  {
    @throw returnValue;
  }
  else if(returnValueIsBoxed)
  {
    if(strcmp([[anInvocation methodSignature] methodReturnType],
              [(NSValue *)returnValue objCType]) != 0)
      [NSException raise:NSInvalidArgumentException
                  format:@"Return value does not match method signature."];
    void *buffer = malloc([[anInvocation methodSignature] methodReturnLength]);
    [returnValue getValue:buffer];
    [anInvocation setReturnValue :buffer];
    free(buffer);
  }
  else
  {
    const char *returnType = [[anInvocation methodSignature] methodReturnType];
    const char *returnTypeWithoutQualifiers = returnType + (strlen(returnType) - 1);
    if(strcmp(returnTypeWithoutQualifiers, @encode(id)) == 0)
      [anInvocation setReturnValue:&returnValue];   
  }
}

NSInvocation setArgument atIndex example ios

setArgument : atIndex :

Sets an argument of the receiver.

- (void)setArgument:(void *)buffer atIndex:(NSInteger)index

Parameters

buffer

An untyped buffer containing an argument to be assigned to the receiver. See the discussion below relating to argument values that are objects.

index

An integer specifying the index of the argument.

Indices 0 and 1 indicate the hidden arguments self and _cmd, respectively; you should set these values directly with the setTarget: and setSelector: methods. Use indices 2 and greater for the arguments normally passed in a message.

Discussion( NSInvocation setArgument atIndex example )

This method copies the contents of buffer as the argument at index. The number of bytes copied is determined by the argument size.

When the argument value is an object, pass a pointer to the variable (or memory) from which the object should be copied:

NSArray *anArray;

[invocation setArgument:&anArray atIndex:3];

This method raises NSInvalidArgumentException if the value of index is greater than the actual number of arguments for the selector.

( NSInvocation setArgument atIndex example )

- (void)hello:(NSString *)hello world:(NSString *)world
{
    NSLog(@"%@ %@!", hello, world);

    NSMethodSignature *signature  = [self methodSignatureForSelector:_cmd];
    NSInvocation      *invocation = [NSInvocation invocationWithMethodSignature:signature];

    [invocation setTarget:self];                    // index 0 (hidden)
    [invocation setSelector:_cmd];                  // index 1 (hidden)
    [invocation setArgument:&hello atIndex:2];      // index 2
    [invocation setArgument:&world atIndex:3];      // index 3

    // NSTimer's always retain invocation arguments due to their firing delay. Release will occur when the timer invalidates itself.
    [NSTimer scheduledTimerWithTimeInterval:1 invocation:invocation repeats:NO];
}

( NSInvocation setArgument atIndex example )

int main() {
    NSAutoreleasePool *pool = [NSAutoreleasePool new];            
    Person *person = [Person new];

    SEL sel = @selector(setName:age:);

    NSMethodSignature *sig = [Person instanceMethodSignatureForSelector:sel];
    NSInvocation *inv = [NSInvocation invocationWithMethodSignature:sig];

    [inv setTarget:person];
    [inv setSelector:sel];

    NSString *name = nil;
    NSNumber *age = nil;

    [inv setArgument:&name atIndex:2];
    [inv setArgument:&age atIndex:3];

    // [inv retainArguments];
    // [inv invoke];

    NSInvocationOperation *op = [[[NSInvocationOperation alloc] initWithInvocation:inv] autorelease];
    NSOperationQueue *queue = [NSOperationQueue new];
    [queue addOperation:op];

    [pool release];
    return 0;
}