Smaller active area for custom UIBarButtonItem

问题

I have a UINavigationBar with a custom UIBarButtonItem (which uses a UIButton as its custom view). The problem is: the active area of the custom button is much too large, if I tap at least 40 pixels outside the button, it still gets registered as a tap on the button. This results in accidental taps. How can I reduce the active area on these buttons?

回答1:

I noticed this weirdness too. I found that using a container UIView fixes this. For example:

UIButton *menuButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 30, 30)];
[menuButton addTarget:self action:@selector(revealMenu:) forControlEvents:UIControlEventTouchUpInside];
[menuButton setImage:[UIImage imageNamed:@"menuIcon"] forState:UIControlStateNormal];
UIView *menuButtonContainer = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 30, 30)];
[menuButtonContainer addSubview:menuButton];
self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:menuButtonContainer];

回答2:

I think u haven't changed the size of the custom button... Try doing this... In Interface builder select the button which u want to reduce the active area and then press "Command+3" or "tools --> Size inspector" in that reduce 'W' and 'H' values... this will make the custom button smaller and so the active area also get reduced...

~Raviraja

回答3:

Are you adding the button through Interface Builder or are you doing it programmatically? Either way, you can use this line of code to set the bounds of the image:

yourButton.bounds = CGRectMake( 0, 0, yourImage.size.width, yourImage.size.height );  

If you want a full example, here's one I used in one of my apps:

    UIImage *image = [UIImage imageNamed:@"audio-off.png"];
    UIButton *myMuteButton = [UIButton buttonWithType:UIButtonTypeCustom];
    myMuteButton.bounds = CGRectMake( 0, 0, image.size.width, image.size.height );    
    [myMuteButton setImage:image forState:UIControlStateNormal];
    [myMuteButton addTarget:self action:@selector(mute) forControlEvents:UIControlEventTouchUpInside];    
    UIBarButtonItem *myMuteBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:myMuteButton];   
    navBar.leftBarButtonItem = myMuteBarButtonItem;
    [myMuteBarButtonItem release];

来源：https://stackoverflow.com/questions/2368120/smaller-active-area-for-custom-uibarbuttonitem