最简单的iPhoneX根据安全区域布局方案

安全区域适配

iPhoneX安全区域

一、自适应的UIView类别

使用 mas_bp_safeAreaLayoutGuideBottom 和 bp_safeAreaInsets 基本能解决iPhoneX适配问题。具体参考后面实例。

//
//  UIView+SafeArea.h
//
 
#import <UIKit/UIKit.h>
#import <View+MASAdditions.h>
 
NS_ASSUME_NONNULL_BEGIN
 
@interface UIView (SafeArea)
 
- (UIEdgeInsets)bp_safeAreaInsets;
 
- (UILayoutGuide *)bp_safeAreaLayoutGuide;
 
#pragma mark - Masonry
- (MASViewAttribute *)mas_bp_safeAreaLayoutGuide;
- (MASViewAttribute *)mas_bp_safeAreaLayoutGuideTop;
- (MASViewAttribute *)mas_bp_safeAreaLayoutGuideBottom;
- (MASViewAttribute *)mas_bp_safeAreaLayoutGuideLeft;
- (MASViewAttribute *)mas_bp_safeAreaLayoutGuideRight;
 
@end
 
NS_ASSUME_NONNULL_END

//
//  UIView+SafeArea.m
//
 
#import "UIView+SafeArea.h"
 
@implementation UIView (SafeArea)
 
- (UIEdgeInsets)bp_safeAreaInsets {
#if defined(__IPHONE_11_0)
    if (@available(iOS 11, *)) {
        return self.safeAreaInsets;
    }
#endif
    return UIEdgeInsetsZero;
}
 
/// UILayoutGuide可以被添加到View中，和View一样可以设置各种约束，参与布局。但是它不会被渲染出来，不会响应事件路由。
- (UILayoutGuide *)bp_safeAreaLayoutGuide {
#if defined(__IPHONE_11_0)
    if (@available(iOS 11, *)) {
        return self.safeAreaLayoutGuide;
    }
#endif
     
    static UILayoutGuide *normalGuide = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        normalGuide = [[UILayoutGuide alloc] init];
        [self addLayoutGuide:normalGuide];
         
        // 约束代码，设置跟self大小完全一样
        [normalGuide.topAnchor constraintEqualToAnchor:self.topAnchor constant:statusBarAndNaviBarHeight].active = YES;
        [normalGuide.leftAnchor constraintEqualToAnchor:self.leftAnchor].active = YES;
        [normalGuide.rightAnchor constraintEqualToAnchor:self.rightAnchor].active = YES;
        [normalGuide.bottomAnchor constraintEqualToAnchor:self.bottomAnchor constant:-bottomSafeHeight].active = YES;
    });
    return normalGuide;
}
 
- (MASViewAttribute *)mas_bp_safeAreaLayoutGuide {
#if defined(__IPHONE_11_0)
    if (@available(iOS 11, *)) {
        return self.mas_safeAreaLayoutGuide;
    }
#endif
    return self.mas_bottom;
}
 
- (MASViewAttribute *)mas_bp_safeAreaLayoutGuideTop {
#if defined(__IPHONE_11_0)
    if (@available(iOS 11, *)) {
        return self.mas_safeAreaLayoutGuideTop;
    }
#endif
    return self.mas_top;
}
 
- (MASViewAttribute *)mas_bp_safeAreaLayoutGuideBottom {
#if defined(__IPHONE_11_0)
    if (@available(iOS 11, *)) {
        return self.mas_safeAreaLayoutGuideBottom;
    }
#endif
    return self.mas_bottom;
}
 
- (MASViewAttribute *)mas_bp_safeAreaLayoutGuideLeft {
#if defined(__IPHONE_11_0)
    if (@available(iOS 11, *)) {
        return self.mas_safeAreaLayoutGuideLeft;
    }
#endif
    return self.mas_left;
}
 
- (MASViewAttribute *)mas_bp_safeAreaLayoutGuideRight {
#if defined(__IPHONE_11_0)
    if (@available(iOS 11, *)) {
        return self.mas_safeAreaLayoutGuideRight;
    }
#endif
    return self.mas_right;
}
 
@end

二、实际使用中 若以上不能达到要求，可以监听安全区域发生变化的回调，重新设置约束

-----在控制器内------
#pragma mark - SafeAreaInsetsDidChange
#if defined(__IPHONE_11_0)
- (void)viewSafeAreaInsetsDidChange {
    [super viewSafeAreaInsetsDidChange];
     
    NSLog(@"safeAreaInset %@", NSStringFromUIEdgeInsets(self.view.bp_safeAreaInsets));
    // iPhoneX系列
    // 竖屏 {44, 0, 34, 0}
    // 横屏 {0, 44, 21, 34}
 
    // 其他机型
    // {20, 0, 0, 0}
}
#endif
 
-----在UIView内------
#pragma mark - SafeAreaInsetsDidChange
#if defined(__IPHONE_11_0)
- (void)safeAreaInsetsDidChange {
    [super safeAreaInsetsDidChange];
     
    NSLog(@"safeAreaInset %@", NSStringFromUIEdgeInsets(self.bp_safeAreaInsets));
}
#endif

• 安全区域发生变化并回调 要求是在iOS11系统以上，并且回调触发在 viewDidAppear之后、layoutSubView之前，所以要注意 viewDidLoad 和 viewSafeAreaInsetsDidChange 两个地方都要设置约束。在 viewDidLoad 设置约束是为了支持 iOS11以前系统。
• 隐藏系统导航栏时： 非刘海屏，iOS11及之后系统，safeAreaInsets.top = 20 ， iOS11之前系统 safeAreaInsets.top = 0 ；不隐藏系统导航栏时 都=0

实例参考

1、自定义navBar，隐藏系统导航栏 (适配顶部)

- (void)viewDidLoad
{
    [super viewDidLoad];

    [self.view addSubview:self.customNavBar];
    
    [self.customNavBar mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.left.right.mas_equalTo(self.view);
        make.height.mas_equalTo(HEIGHT_STATUSBAR + 44);
    }];
}

/// 横竖屏切换时：状态栏高度会发生变化

#ifdef __IPHONE_11_0
- (void)viewSafeAreaInsetsDidChange {
    [super viewSafeAreaInsetsDidChange];
    [self.customNavBar mas_updateConstraints:^(MASConstraintMaker *make) {
        make.height.mas_equalTo(self.view.bp_safeAreaInsets.top + 44);
    }];
}
#endif

2、这个VC的整个页面是个tableView，iPhoneX机器时底部34pt不建议用，特别是某些页面底部是个UIButton时 （适配底部）

///方法一：使用mas_bp_safeAreaLayoutGuideBottom

- (void)viewDidLoad
{
    [super viewDidLoad];

    [self.view addSubview:self.tableView];

    [_tableView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.left.right.mas_equalTo(self.view);
        make.bottom.mas_equalTo(self.view.mas_bp_safeAreaLayoutGuideBottom);
    }];
}

///方法二：使用self.view.bp_safeAreaInsets.bottom

- (void)viewSafeAreaInsetsDidChange
{
    [super viewSafeAreaInsetsDidChange];
    
    [_tableView mas_updateConstraints:^(MASConstraintMaker *make) {
        make.bottom.mas_equalTo(self.view.mas_bottom).mas_offset(-self.view.bp_safeAreaInsets.bottom);
        //如果需求是对齐到底部，只需删除`bp_safeAreaInsets.bottom`
        //make.bottom.mas_equalTo(self.view.mas_bottom);
    }];
}

引用：

safeArea详解
Masonry+safeArea适配