What exactly IS the highlighted image in a UIImageView?

Question

This question boggles my mind and I cannot find an answer. I looked all over the documentation, tried out code, and searched Google, but I can't find anything. The UIImageView in iOS programming can have an image set to it, but you can also set a highlighted image to it. What exactly is this highlighted image?

Answer 1

you can set two different images to an UIImageView, one to its image property, another to its highlightedImage property.

There are many cases where you want to change the state of the image (eg: a checkmark) from off to on or vice versa. in that case, instead of you setting the UIImageView's image to the appropriate one everytime, you can just say

theCheckMarkImageView.image = regularImage;//set the regular image theCheckMarkImageView.highLightedImage = highlightedImage; 

(based on your logic show it highlighted or not).

theCheckMarkImageView.highlighted = YES/NO; 

In addition to all this, do check Ethan Huang's answer about how tabelviewcell works with this property. Quite useful if you are showing different images based on cell selection.

Answer 2

highlightedImage use for highlight ImageView,simple.

imageView.highlightedImage = [UIImage imageNamed:@"hightlighted.png"]; imageView.highlighted = YES; 

Don't need to waste time to search or read a lot. Objective-C is meaningful language. Just drag ImageView and make a try code, step by step test all property, method in UIImageView.h(in UIKit framework) and you'll understand. Do the same with other UI element.