How to add UIbutton on UIView programmatically using Autolayouts

Question

hi i am beginner in objective in my project i have to add button on UIview programmatically using autolayouts and i tried my level best but result is not coming please help me some one else

and this is my code

 UIView * myView;
 myView = [UIView new];
    myView.translatesAutoresizingMaskIntoConstraints = NO;
    myView.backgroundColor = [UIColor colorWithRed:0.95 green:0.47 blue:0.48 alpha:1.0];
    [self.view addSubview:myView];

UIButton *mainButton;
mainButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[mainButton setTitle:@"MainButton" forState:UIControlStateNormal];
[mainButton sizeToFit];
mainButton.backgroundColor = [UIColor blackColor];
mainButton.translatesAutoresizingMaskIntoConstraints = NO;
[self.view addSubview:mainButton];

//Adding myview on UIview

constraint = [NSLayoutConstraint constraintWithItem:myView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeading multiplier:1.0f constant:30.0f];
    [self.view addConstraint:constraint];

    constraint = [NSLayoutConstraint constraintWithItem:myView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1.0f constant:100.0f];
    [self.view addConstraint:constraint];

    constraint = [NSLayoutConstraint constraintWithItem:myView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem: nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0f constant:100.0f];
    [self.view addConstraint:constraint];

    constraint = [NSLayoutConstraint constraintWithItem:myView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem: nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0f constant:100.0f];
    [self.view addConstraint:constraint];

//Adding button on myview:-

constraint = [NSLayoutConstraint constraintWithItem:mainButton attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:myView attribute:NSLayoutAttributeLeading multiplier:1.0f constant:20.f];
    [self.view addConstraint:constraint];

    constraint = [NSLayoutConstraint constraintWithItem:mainButton attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:myView attribute:NSLayoutAttributeTop multiplier:1.0f constant:30.0f];
    [self.view addConstraint:constraint];

but result is not coming just there added myview but button is not adding on my view and i want result like below image formate plese help me some one

Answer 1

我认为您应该将UIButton作为子视图添加到myView，而不是self.view。