如何借助标签更改按钮的图像？

Question

How i can change the image on button when i have only tag of that button. for instance I have 20 buttons and tag is set 0 to 19. now in a response of some action i have the tag 5 of that button and now i want to change the image of that button. how could it possible? Please help

Answer 1

I think you can use it:

for (UIButton *button in self.view.subviews) {
        if (button.tag == 5) {
            [button setBackgroundImage:[UIImage imageNamed:@"new-imagepng"] forState:UIControlStateNormal];
        }
    }

But I didn't check it.

Answer 2

The following code gives you the button you are after ( superView refers to whatever view is holding your button):

UIButton *button5 = [superView viewWithTag:5];

Then you can amend the properties of the button as you see fit.

Answer 3

UIButton *button = (UIButton *)[myView viewWithTag:myTag];
[button setImage:... forState:...];

The myView variable is superview of the 20buttons. You can get UIButton object from the tag and can set image for your state.

Answer 4

Make the action of all buttons the same, say @(selector)buttonPressed: . Then in your handler do this:

-(void)buttonPressed:(id)sender {
  UIButton *button = (UIButton *) sender;
  int tag = button.tag; 
  // respond as you wish using tag... for example:
  UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:@"img%02d.png", tag]];
  [button setImage:image forState:UIControlStateNormal];
}

One more warning: better use integers 1 through 20 rather than 0 through 19. This way you avoid mistakes that might arise out of the fact that the default tag of every UIView is set to 0.