ios - 以编程方式使用自动布局

Question

我尝试使用 UIView 实现以下设计，它应该全部使用自动布局完成并且没有硬编码框架:

我用这样的“for 循环”来完成它:

CGFloat y_coordinate = 0;

for(int i = 0;i < 3;i++)
{

   UIView * testView =  [UIView new];

   testView.frame = CGRectMake(testView.frame.origin.x, y_coordinate, testView.frame.size.width, testView.frame.size.height);

    testView.translatesAutoresizingMaskIntoConstraints = NO;

    NSDictionary *viewsDictionary = @{@"testView":testView};

    testView.backgroundColor = [UIColor redColor];

    [self.view addSubview:testView];

    //View should have the same Width and Height and a little Padding between them!
    [self.view addConstraint:[NSLayoutConstraint constraintWithItem:testView
                                                          attribute:NSLayoutAttributeWidth
                                                          relatedBy:NSLayoutRelationEqual
                                                             toItem:self.view
                                                          attribute:NSLayoutAttributeWidth
                                                         multiplier:0.5
                                                           constant:-4]];

    [self.view addConstraint:[NSLayoutConstraint constraintWithItem:testView
                                                          attribute:NSLayoutAttributeWidth
                                                          relatedBy:NSLayoutRelationEqual
                                                             toItem:testView
                                                          attribute:NSLayoutAttributeHeight
                                                         multiplier:1
                                                           constant:-4]];

    if(i % 2) {

        //odd

        [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:[testView]-0-|"
                                                                          options:0
                                                                          metrics:nil
                                                                            views:viewsDictionary]];

       //Here i need the Height of the View and not hard coded like here...but how?

           y_coordinate += 200;

    } else {

          //even

        [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[testView]"
                                                                          options:0
                                                                          metrics:nil
                                                                            views:viewsDictionary]];


    } 
}

我的问题是我不知道如何使用自动布局将 View 正确地放置在彼此之下？

Answer 1

我给你的建议是在线学习自动布局教程，清楚地了解 View 在“自动布局”下是如何布局的。 一个这样的例子就是 Ray Wenderlich 的教程。虽然本教程并未专门介绍以编程方式进行自动布局，但它确实让您清楚地了解如何借助自动布局功能放置 View 。 http://www.raywenderlich.com/50317/beginning-auto-layout-tutorial-in-ios-7-part-1