Setting an image for a UIButton in code

Question

Objective-C

UIImage *btnImage = [UIImage imageNamed:@"image.png"];
[btnTwo setImage:btnImage forState:UIControlStateNormal];

Swift 5.1

let btnImage = UIImage(named: "image")
btnTwo.setImage(btnImage , for: .normal)

Mike's solution will just show the image, but any title set on the button will not be visible, because you can either set the title or the image.

If you want to set both (your image and title) use the following code:

btnImage = [UIImage imageNamed:@"image.png"];
[btnTwo setBackgroundImage:btnImage forState:UIControlStateNormal];
[btnTwo setTitle:@"Title" forState:UIControlStateNormal];

Before this would work for me I had to resize the button frame explicitly based on the image frame size.

UIImage *listImage = [UIImage imageNamed:@"list_icon.png"];
UIButton *listButton = [UIButton buttonWithType:UIButtonTypeCustom];

// get the image size and apply it to the button frame
CGRect listButtonFrame = listButton.frame;
listButtonFrame.size = listImage.size;
listButton.frame = listButtonFrame;

[listButton setImage:listImage forState:UIControlStateNormal];
[listButton addTarget:self.navigationController.parentViewController 
               action:@selector(revealToggle:) 
     forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem *jobsButton = 
  [[UIBarButtonItem alloc] initWithCustomView:listButton];

self.navigationItem.leftBarButtonItem = jobsButton;

In case of Swift User

// case of normal image
let image1 = UIImage(named: "your_image_file_name_without_extension")!
button1.setImage(image1, forState: UIControlState.Normal) 

// in case you don't want image to change when "clicked", you can leave code below
// case of when button is clicked
let image2 = UIImage(named: "image_clicked")!
button1.setImage(image2, forState: UIControlState.Highlight) 

You can do it like this

[btnTwo setImage:[UIImage imageNamed:@"image.png"] forState:UIControlStateNormal];

UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
btn.frame = CGRectMake(0, 0, 150, 44);
[btn setBackgroundImage:[UIImage imageNamed:@"buttonimage.png"] 
               forState:UIControlStateNormal];
[btn addTarget:self 
     action:@selector(btnSendComment_pressed:) 
     forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:btn];