如何使用自动布局水平设置三个按钮而无间隙

Question

I have a requirement where , i try to set 3 buttons at the bottom of the view horizontally placed without any gap . I have attached a screen shot of how i need to show and another showing how it displays currently.

i am using the following constraint programatically to set this

NSDictionary *views = NSDictionaryOfVariableBindings(btnCreateAccount,btnForgotuserid,btnForgotPassword);

[self.view addConstraint:[NSLayoutConstraint constraintWithItem:btnCreateAccount attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeBottom multiplier:1 constant:0]];

[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[btnCreateAccount][btnForgotuserid(==btnCreateAccount)][btnForgotPassword(==btnCreateAccount)]|" options:NSLayoutFormatAlignAllBottom metrics:nil views:views]];

Please help me in solving this issue

EDIT : In iOS 7 , see the screen shot

Thanks, Vinod.

Answer 1

I have tried your code and the constraints seem to work fine. The problem might be somewhere else.

This is the code I have tried, created all buttons programmatically:

UIButton *b1 = [[UIButton alloc] init];
UIButton *b2 = [[UIButton alloc] init];
UIButton *b3 = [[UIButton alloc] init];

for (UIButton *b in @[b1, b2, b3]) {
    [b setTranslatesAutoresizingMaskIntoConstraints:NO];
    [self.view addSubview:b];
    [b.layer setBorderWidth:1];
}
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:b1 attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeBottom multiplier:1 constant:0]];

[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[b1]-0-[b2(==b1)]-0-[b3(==b1)]-0-|" options:NSLayoutFormatAlignAllBottom metrics:nil views:@{ @"b1":b1, @"b2":b2, @"b3":b3 }]];

Make sure you are calling setTranslatesAutoresizingMaskIntoConstraints:NO on your buttons. If you create them in the storyboard, you need to remove the implicit constraints that are added there.

Let me know how this goes and if you need more help.