How to change the icon of an image to represent it has been selected on an iPhone.

Question

I am trying to simulate the same behaviour as the defaults "Photos" application found on the iPhone OS 3.X-4.0. Basically when the user selects multiple photos in the Album via the UIImagePickerController from the Image Library,an icon (tick mark) appears on the image to represent that the image has been selected by the user. How to implement this functionality.

Many thanks

Answer 1

create another UIImageView with the tickmark-image and add it as a subview to your selected UIImageView. Like this:

- (void)putCheckmarkOnImageView:(UIImageView *)anImageView {
    UIImageView *newIV = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"checkmark.png"]];
    newIV.tag = 42;
    CGPoint newIVPosition = CGPointMake(anImageView.bounds.size.width - newIV.bounds.size.width, 
                                        anImageView.bounds.size.height - newIV.bounds.size.height);
    CGRect newFrame = newIV.frame;
    newFrame.origin = newIVPosition;
    newIV.frame = newFrame;
    [anImageView addSubview:newIV];
    [newIV release];
}   

- (void)removeCheckmarkOnImageView:(UIImageView *)anImageView {
    [[anImageView viewWithTag:42] removeFromSuperview];
}