IOS开发中topLayoutGuide与bottomLayoutGuide的使用小技巧
在IOS开发的过程中我们经常会遇到一些紧贴tabbar有工具条之类的页面,比如说购买、支付等页面,往往这些页面有时候在栈底显示(页面有tabbar),有时不在(页面没有tabbar)。比如:
这种页面对于常规的做法是有tabbar的时候设置一套约束,没有tabbar的时候更新一下约束。但是苹果提过了一个bottomLayoutGuide可以让我们更优雅的处理这类问题。
代码如下:
_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); }];
搭配Masonry,使用Masonry提供的mas_bottomLayoutGuide仅需一行我们就可以实现这样的效果。
同样来说这种效果对于navigationBar也适用——topLayoutGuide。对应的Masonry使用方法是mas_topLayoutGuide。
完整代码(代码量太少就不给完整的链接了):
#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