使用Objective-C实现苹果官方NSLayoutConstraint页面布局

在iOS开发中，使用Auto Layout可以创建灵活且适应性强的用户界面。本文将通过几个简单的例子，展示如何利用Objective-C中的NSLayoutConstraint来实现这一目标。

首先，我们需要导入必要的头文件，并设置基本的视图控制器类：

#import "ViewController.h" @interface ViewController () @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; [self setupViews]; } -(void)setupViews{ [self addAndConstraintButton]; [self addAndConstraintViews]; } -(void)addAndConstraintButton{ UIButton *button = [[UIButton alloc] init]; [button setTitle:@"点击我" forState:UIControlStateNormal]; [button setTitleColor:[UIColor redColor] forState:UIControlStateNormal]; button.backgroundColor = [UIColor orangeColor]; [self.view addSubview:button]; // 关闭自动调整大小功能，启用Auto Layout button.translatesAutoresizingMaskIntoCOnstraints= NO; // 创建水平方向上的约束 NSArray *horizOntalConstraints= [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-100-[button]-100-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(button)]; // 创建垂直方向上的约束 NSArray *verticalCOnstraints= [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-100-[button(100)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(button)]; [self.view addConstraints:horizontalConstraints]; [self.view addConstraints:verticalConstraints]; } -(void)addAndConstraintViews{ UIView *view1 = [[UIView alloc] init]; UIView *view2 = [[UIView alloc] init]; UIView *view3 = [[UIView alloc] init]; view1.backgroundColor = [UIColor redColor]; view2.backgroundColor = [UIColor orangeColor]; view3.backgroundColor = [UIColor purpleColor]; view1.translatesAutoresizingMaskIntoCOnstraints= NO; view2.translatesAutoresizingMaskIntoCOnstraints= NO; view3.translatesAutoresizingMaskIntoCOnstraints= NO; [self.view addSubview:view1]; [self.view addSubview:view2]; [self.view addSubview:view3]; // 创建水平方向上的约束 NSArray *horizOntalConstraints= [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-10-[view1]-10-[view2(==view1)]-10-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(view1, view2)]; // 创建垂直方向上的约束 NSArray *verticalConstraints1 = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-10-[view2]-10-[view3(==view2)]-10-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(view2, view3)]; NSArray *verticalConstraints2 = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-10-[view1]-10-[view3]-10-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(view1, view3)]; [self.view addConstraints:horizontalConstraints]; [self.view addConstraints:verticalConstraints1]; [self.view addConstraints:verticalConstraints2]; } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // 清理可以重新创建的资源 } @end 

以上代码演示了如何使用Auto Layout来布局按钮和视图。通过关闭自动调整大小功能并添加适当的约束，我们可以确保界面元素在不同的设备上都能保持良好的布局效果。

转自：原作者博客链接