view.png

@interface ViewController ()
@property(nonatomic,strong)UIView  *safeview;
@property(nonatomic,strong)UIButton *topButton;
@end

static inline UIEdgeInsets safeArea_Inset(UIView *view) {
    
    if (@available(iOS 11.0, *)) {
        
        return view.safeAreaInsets;
        
    }
    
    return UIEdgeInsetsZero;
    
}

static inline CGRect zj_layoutFrame(UIView *view) {
    
    if (@available(iOS 11.0, *)) {
        
        return view.safeAreaLayoutGuide.layoutFrame;
        
    }
    
    return view.frame;
    
}

@implementation ViewController
-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    //NSLog(@"viewWillAppear: %@", self);
   
    UIEdgeInsets safeAreaInsets = safeArea_Inset(self.view);
    NSLog(@"%s\n %@ \n%@", __func__, NSStringFromUIEdgeInsets(safeAreaInsets),NSStringFromCGRect(zj_layoutFrame(self.view)));
}
-(void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
    UIEdgeInsets safeAreaInsets = safeArea_Inset(self.view);
    NSLog(@"%s\n %@ \n%@", __func__, NSStringFromUIEdgeInsets(safeAreaInsets),NSStringFromCGRect(zj_layoutFrame(self.view)));
}
-(void)viewWillLayoutSubviews{
    [super viewWillLayoutSubviews];
    UIEdgeInsets safeAreaInsets = safeArea_Inset(self.view);
     NSLog(@"%s\n %@ \n%@", __func__, NSStringFromUIEdgeInsets(safeAreaInsets),NSStringFromCGRect(zj_layoutFrame(self.view)));
}
- (void)viewDidLayoutSubviews {
    
    [super viewDidLayoutSubviews];
    
    UIEdgeInsets safeAreaInsets = safeArea_Inset(self.view);
     NSLog(@"%s\n %@ \n%@", __func__, NSStringFromUIEdgeInsets(safeAreaInsets),NSStringFromCGRect(zj_layoutFrame(self.view)));
}

-(void)viewWillDisappear:(BOOL)animated{
    [super viewWillDisappear:animated];
    UIEdgeInsets safeAreaInsets = safeArea_Inset(self.view);
     NSLog(@"%s\n %@ \n%@", __func__, NSStringFromUIEdgeInsets(safeAreaInsets),NSStringFromCGRect(zj_layoutFrame(self.view)));
}

-(void)viewDidDisappear:(BOOL)animated{
    [super viewDidDisappear:animated];
    
    UIEdgeInsets safeAreaInsets = safeArea_Inset(self.view);
     NSLog(@"%s\n %@ \n%@", __func__, NSStringFromUIEdgeInsets(safeAreaInsets),NSStringFromCGRect(zj_layoutFrame(self.view)));
}

-(void)viewSafeAreaInsetsDidChange{
    [super viewSafeAreaInsetsDidChange];
    UIEdgeInsets safeAreaInsets = safeArea_Inset(self.view);
     NSLog(@"%s\n %@ \n%@", __func__, NSStringFromUIEdgeInsets(safeAreaInsets),NSStringFromCGRect(zj_layoutFrame(self.view)));
}

-(void)viewLayoutMarginsDidChange{
    [super viewLayoutMarginsDidChange];
    UIEdgeInsets safeAreaInsets = safeArea_Inset(self.view);
     NSLog(@"%s\n %@ \n%@", __func__, NSStringFromUIEdgeInsets(safeAreaInsets),NSStringFromCGRect(zj_layoutFrame(self.view)));
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    UIEdgeInsets safeAreaInsets = safeArea_Inset(self.view);
     NSLog(@"%s\n %@ \n%@", __func__, NSStringFromUIEdgeInsets(safeAreaInsets),NSStringFromCGRect(zj_layoutFrame(self.view)));
    
    [self buildlBottomLayoutGuide];
}

-(void)buildlBottomLayoutGuide {
    self.topButton = [UIButton buttonWithType:UIButtonTypeCustom];
    self.topButton.backgroundColor = [UIColor orangeColor];
    self.topButton.translatesAutoresizingMaskIntoConstraints = NO;
    [self.topButton addTarget:self action:@selector(ppt1) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:self.topButton];
    
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-20-[topButton(100)]" options:NSLayoutFormatDirectionLeadingToTrailing metrics:@{} views:@{@"topButton":self.topButton}]];
    
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[topLayoutGuide]-20-[topButton(100)]" options:NSLayoutFormatDirectionLeadingToTrailing metrics:@{} views:@{@"topButton":self.topButton,@"topLayoutGuide":self.topLayoutGuide}]];
    
    [self.view addSubview:self.safeview];
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(ppt)];
    [self.safeview addGestureRecognizer:tap];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-20-[safeview(100)]" options:NSLayoutFormatDirectionLeadingToTrailing metrics:@{} views:@{@"safeview":self.safeview}]];
    
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[safeview(100)]-20-[bottomLayoutGuide]" options:NSLayoutFormatDirectionLeadingToTrailing metrics:@{} views:@{@"safeview":self.safeview,@"bottomLayoutGuide":self.bottomLayoutGuide}]];
}

-(void)ppt1 {
    if (@available(iOS 11.0, *)) {
        
        self.additionalSafeAreaInsets = UIEdgeInsetsMake(50, 0, 60, 0);
        
    }
    
}
-(void)ppt{
    id obc = [[NSClassFromString(@"xxx") alloc] init];
    
    [self.navigationController pushViewController:obc animated:YES];
}
-(UIView*)safeview{
    if (!_safeview) {
        _safeview = [UIView new];
        _safeview.translatesAutoresizingMaskIntoConstraints = NO;
        _safeview.backgroundColor = [UIColor redColor];
    }
    return _safeview;
}

运行看到控制打印的执行顺序及 安全区域的变化：

2017-11-16 15:49:35.984279+0800 safe[58767:5415421] -[ViewController viewDidLoad]
 {0, 0, 0, 0} 
{{0, 0}, {375, 812}}
2017-11-16 15:49:35.986049+0800 safe[58767:5415421] -[ViewController viewWillAppear:]
 {0, 0, 0, 0} 
{{0, 0}, {375, 812}}
2017-11-16 15:49:35.986906+0800 safe[58767:5415421] -[ViewController viewLayoutMarginsDidChange]
 {88, 0, 34, 0} 
{{0, 0}, {375, 812}}
2017-11-16 15:49:35.987287+0800 safe[58767:5415421] -[ViewController viewSafeAreaInsetsDidChange]
 {88, 0, 34, 0} 
{{0, 88}, {375, 690}}
2017-11-16 15:49:35.988129+0800 safe[58767:5415421] -[ViewController viewWillLayoutSubviews]
 {88, 0, 34, 0} 
{{0, 88}, {375, 690}}
2017-11-16 15:49:35.988625+0800 safe[58767:5415421] -[ViewController viewDidLayoutSubviews]
 {88, 0, 34, 0} 
{{0, 88}, {375, 690}}
2017-11-16 15:49:36.046169+0800 safe[58767:5415421] -[ViewController viewDidAppear:]
 {88, 0, 34, 0} 
{{0, 88}, {375, 690}}

点击橙色按钮看其安全区域变化：

safe.png

2017-11-16 15:55:50.658061+0800 safe[58767:5415421] -[ViewController viewLayoutMarginsDidChange]
 {138, 0, 94, 0} 
{{0, 88}, {375, 690}}
2017-11-16 15:55:50.658297+0800 safe[58767:5415421] -[ViewController viewSafeAreaInsetsDidChange]
 {138, 0, 94, 0} 
{{0, 138}, {375, 580}}
2017-11-16 15:55:50.658620+0800 safe[58767:5415421] -[ViewController viewWillLayoutSubviews]
 {138, 0, 94, 0} 
{{0, 138}, {375, 580}}
2017-11-16 15:55:50.658877+0800 safe[58767:5415421] -[ViewController viewDidLayoutSubviews]
 {138, 0, 94, 0} 
{{0, 138}, {375, 580}}