How to compare self.button.currentImage to an image?

Question

I am trying to create a button represented by an image which whenever is pressed changes the image to the other one so that I can know which image is currently selected.

- (IBAction)imageWasPressed:(id)sender {
   UIImage *imageWork = [UIImage imageNamed:@"icn_work"];
NSData *data1 = UIImagePNGRepresentation(self.imageButton.currentImage);
NSData *data2 = UIImagePNGRepresentation(imageWork);

if (data1==data2){
    [self.imageButton setImage:[UIImage imageNamed:@"icn_personal"] forState:UIControlStateNormal];}
}

I have also tried this but it didn't work:

- (IBAction)imageWasPressed:(id)sender {
if ([[self.imageButton imageForState:UIControlStateNormal] isEqual:[UIImage imageNamed:@"icn_work"]]){
    [self.imageButton setImage:[UIImage imageNamed:@"icn_personal"] forState:UIControlStateNormal];}
}

The line which changes the images works but I can't compare the two images. Any help would be much appreciated! Thank you!

Also, as an aside, you probably shouldn't be comparing images to get this information. Keep a BOOL like, `if (self.personalSelected)` changing that when a button is selected instead. — dalton_c, Jul 21 '14 at 18:23
@daltonclaybrook I've tried it before and it didn't work. It seems that it is working now, lol? Thanks a lot for your answer! — Toma Radu-Petrescu, Jul 21 '14 at 18:25
Check this: http://stackoverflow.com/questions/11216167/objective-c-comparing-an-image-against-another-image-that-has-been-previously-s — arturdev, Jul 21 '14 at 18:31

SwiftArchitect · Accepted Answer · 2014-07-21T18:50:31.143

2

This is rather unconventional approach, and I would recommend keeping track of your selection some other way.

But to answer the issue at hand, it does not work because you are comparing pointers, not data. data1 * will always be different to data2 *.

From the documentation: isEqualToData: Compares the receiving data object to otherData.

- (BOOL)isEqualToData:(NSData *)otherData

edited Jul 21 '14 at 18:50

answered Jul 21 '14 at 18:23

SwiftArchitect

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score 2 · Answer 2 · answered Jul 21 '14 at 18:23

If you want to change button image regarding it's state you can assign different images for different states.

[self.imageButton setImage:image1 forState:UIControlStateNormal];
[self.imageButton setImage:image2 forState:UIControlStateHighlighted];
[self.imageButton setImage:image3 forState:UIControlStateSelected];

Since you can get button state and you know what image you set for the state you can get image as well.

score 0 · Answer 3 · answered Jul 21 '14 at 18:22

0

if ([data1 isEqualToData: data2])

instead of

if (data1==data2)

answered Jul 21 '14 at 18:22

Frans Raharja Kurniawan

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How to compare self.button.currentImage to an image?

3 Answers3