iOS开发之topLayoutGuide和bottomLayoutGuide的使用小技巧分享

_bottomView = [UIView new];
 _bottomView.backgroundColor = [UIColor yellowColor];
 [self.view addSubview:_bottomView];
 [_bottomView mas_makeConstraints:^(MASConstraintMaker *make) {
  make.height.equalTo(@40);
  make.left.and.right.equalTo(self.view);
  make.bottom.equalTo(self.mas_bottomLayoutGuide);
 }];

#import "ViewController.h"
#import "Masonry.h"
@interface ViewController ()
@property (strong, nonatomic) UIView *topView;
@property (strong, nonatomic) UIView *bottomView;
@end

@implementation ViewController

- (void)viewDidLoad {
 [super viewDidLoad];
 // Do any additional setup after loading the view, typically from a nib.
 UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
 btn.frame = CGRectMake(0, 164, 80, 50);
 [btn setTitle:@"top" forState:UIControlStateNormal];
 btn.backgroundColor = [UIColor redColor];
 [btn addTarget:self action:@selector(topClick) forControlEvents:UIControlEventTouchUpInside];
 [self.view addSubview:btn];

 UIButton *btn1 = [UIButton buttonWithType:UIButtonTypeCustom];
 btn1.backgroundColor = [UIColor yellowColor];
 btn1.frame = CGRectMake(0, 264, 80, 50);
 [btn1 setTitle:@"bottom" forState:UIControlStateNormal];
 [btn1 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
 [btn1 addTarget:self action:@selector(bottomClick) forControlEvents:UIControlEventTouchUpInside];
 [self.view addSubview:btn1];
 [self initView];
}

- (void)initView {
 _topView = [UIView new];
 _topView.backgroundColor = [UIColor greenColor];
 [self.view addSubview:_topView];
 [_topView mas_makeConstraints:^(MASConstraintMaker *make) {
  make.height.equalTo(@40);
  make.left.and.right.equalTo(self.view);

  make.top.equalTo(self.mas_topLayoutGuide);

 }];

 _bottomView = [UIView new];
 _bottomView.backgroundColor = [UIColor yellowColor];
 [self.view addSubview:_bottomView];
 [_bottomView mas_makeConstraints:^(MASConstraintMaker *make) {
  make.height.equalTo(@40);
  make.left.and.right.equalTo(self.view);
  make.bottom.equalTo(self.mas_bottomLayoutGuide);
 }];
}
- (void)topClick{

 [self.navigationController setNavigationBarHidden:!self.navigationController.navigationBarHidden animated:NO];
// [self updateViewConstraints];
}
- (void)bottomClick{

 [self.navigationController setToolbarHidden:!self.navigationController.toolbarHidden animated:NO];
 // 手动触发updateViewConstraints
// [self updateViewConstraints];
}
- (void)didReceiveMemoryWarning {
 [super didReceiveMemoryWarning];
 // Dispose of any resources that can be recreated.
}

@end

  UIButton *button = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
  [self.view addSubview:button];
  
  [button setTranslatesAutoresizingMaskIntoConstraints: NO];

  // 得到当前视图的最低基准限制，这个是对于Auto Layout constraint来说的。
  id bottomGuide = self.bottomLayoutGuide;
  NSDictionary *viewsDictionary = NSDictionaryOfVariableBindings (button, bottomGuide);
  [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat: @"V:[button]-20-[bottomGuide]"
                                   options: 0
                                   metrics: nil
                                    views: viewsDictionary]];
  
  [self.view layoutSubviews];