如何使用自动布局在 ios 中以编程方式在 UIview 上添加 UIbutton答案

【问题标题】：How to add UIbutton on UIview programmatically in ios using autolayouts如何使用自动布局在 ios 中以编程方式在 UIview 上添加 UIbutton
【发布时间】：2015-07-14 10:20:12
【问题描述】：

我想使用自动布局以编程方式在 UIview 上添加 uibutton 并尝试了一些代码，但它不起作用请帮帮我

//使用自动布局添加UIview

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];

  NSLayoutConstraint * 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];

使用自动布局在 uiview 上添加按钮：-

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

 NSLayoutConstraint *constraint = [NSLayoutConstraint constraintWithItem:mainButton attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:myview attribute:NSLayoutAttributeLeading multiplier:1.0f constant:30.f];
    [self.view addConstraint:constraint];

    constraint = [NSLayoutConstraint constraintWithItem:mainButton attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:myview attribute:NSLayoutAttributeTop multiplier:1.0f constant:30.f];
    [self.view addConstraint:constraint];

constraint = [NSLayoutConstraint constraintWithItem:mainButton attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationGreaterThanOrEqual toItem:nil attribute:NSLayoutAttributeWidth multiplier:1.0f constant:20.f];
    [self.view addConstraint:constraint];

constraint = [NSLayoutConstraint constraintWithItem:mainButton attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationGreaterThanOrEqual toItem:nil attribute:NSLayoutAttributeHeight multiplier:1.0f constant:20.f];
    [self.view addConstraint:constraint];

但是 myview 上没有添加按钮，请帮帮我

【问题讨论】：

标签： ios objective-c

【解决方案1】：

这是有效的：

UIView *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];

NSLayoutConstraint * 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:140.0f];
[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];

UIButton *mainButton = [UIButton new];

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

NSLayoutConstraint *constraint1 = [NSLayoutConstraint constraintWithItem:mainButton attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:myView attribute:NSLayoutAttributeLeading multiplier:1.0f constant:30.f];
[self.view addConstraint:constraint1];

constraint1 = [NSLayoutConstraint constraintWithItem:mainButton attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:myView attribute:NSLayoutAttributeTop multiplier:1.0f constant:30.f];
[self.view addConstraint:constraint1];

constraint1 = [NSLayoutConstraint constraintWithItem:mainButton attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationGreaterThanOrEqual toItem:nil attribute:NSLayoutAttributeWidth multiplier:1.0f constant:20.f];
[self.view addConstraint:constraint1];

constraint1 = [NSLayoutConstraint constraintWithItem:mainButton attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationGreaterThanOrEqual toItem:nil attribute:NSLayoutAttributeHeight multiplier:1.0f constant:20.f];
[self.view addConstraint:constraint1];

【讨论】：

【解决方案2】：

您还没有为按钮定义高度限制，您已经定义了两次宽度限制。

【讨论】：