CODEWITHSUNDEEP
iosobjective-cprotocolsblock
Halpo
Halpo

Reputation: 3134

use completion block from another function

I have an image cropping function with a delegate method that returns the cropped image and the CGRect. how can I return this in my custom completion block that is in another function?

Is there a way to make a reference to that block so I can use it in another function?

hard to explain, but here is my code:

- (void)cropImage:(UIImage *)image type:(NSInteger)type target:(id)target complete:(cropComplete)complete {
    CGFloat ratio;
    switch (type) {
        case 1:
            //16:9
            ratio = 16/9.0;
            break;
        case 2:
            //4:3
            ratio = 4/3.0;
            break;
        case 3:
            //1:1
            ratio = 1;
            break;

        default:
            break;
    }
    ImageCropViewController *vc = [ImageCropViewController new];
    vc.delegate = self;
    vc.imageToCrop = image;
    vc.ratio = ratio;
    UIViewController *targetVC = (UIViewController *)target;
    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:vc];
    [targetVC presentViewController:nav animated:YES completion:nil];
}

//this is the delegate from ImageCropViewController above
- (void)doneCropping:(UIImage *)croppedImage rect:(CGRect)rect {
    (I want the image and CGRect here to return in the ^cropComplete block above)
}

Upvotes: 0

Views: 96

Answers (2)

ZeMoon
ZeMoon

Reputation: 20274

You can simply save the block to be called later in an instance variable.

@implementation WhateverClass
{
    cropComplete cropCompleteBlock;
}

- (void)cropImage:(UIImage *)image type:(NSInteger)type target:(id)target complete:(cropComplete)complete {
    cropCompletionBlock = complete;
    CGFloat ratio;
    switch (type) {
        case 1:
            //16:9
            ratio = 16/9.0;
            break;
        case 2:
            //4:3
            ratio = 4/3.0;
            break;
        case 3:
            //1:1
            ratio = 1;
            break;

        default:
            break;
    }
    ImageCropViewController *vc = [ImageCropViewController new];
    vc.delegate = self;
    vc.imageToCrop = image;
    vc.ratio = ratio;
    UIViewController *targetVC = (UIViewController *)target;
    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:vc];
    [targetVC presentViewController:nav animated:YES completion:nil];
}

//this is the delegate from ImageCropViewController above
- (void)doneCropping:(UIImage *)croppedImage rect:(CGRect)rect {
    cropCompletionBlock(croppedImage);
    cropCompletionBlock = nil;
}

@end

Upvotes: 1

Greg
Greg

Reputation: 25459

Add a new property of type of the block you want to call later (^(cropComplete)) to your class.

Inside cropImage:type:target:complete: function save the block to your property:

self.myNewBlockProperty = complete;

and inside doneCropping:rect call the property.

You cannot access the 'complete' argument inside other function but you can save it in another variable/property and you can access it with no problem.

Upvotes: 2

Related Questions