一、屏幕尺寸

1、规格：

iPhone X 的屏幕宽度同 iPhone 6、iPhone 6s、iPhone 7 和 iPhone 8 的 4.7 英寸屏幕宽度相同，即 375pt。屏幕垂直高度增加了 145pt，这意味着增加了 20% 的可视空间。


竖屏规格：1125px × 2436px (375pt × 812pt @3x)
横屏规格：2436px × 1125px (812pt × 375pt @3x)

2、状态栏

高度增加了24像素


来电或者热点不会导致状态栏高度变化：



3、底部栏

TabBar高度增加了34像素


UITabBar: 0x7f94ca71a7b0; frame = (0 729; 375 83);

ToolBar高度不变，只是向上偏移了34像素

UIToolbar: 0x7f89c7c0b9e0; frame = (0 730; 375 48);

二、设计原则

1、所有设计的内容（不包括滚动列表）不要被屏幕圆角、上方传感器区域和下方home键指示器区域遮挡。



2、提供全屏用户体验，这里主要是指列表要延展到屏幕底部。



3、避免将可交互控件放在屏幕底部或者屏幕圆角区域，防止视觉遮挡和系统边缘手势冲突。



4、不要刻意遮挡和和引导屏幕的关键位置，比如用纯黑色的navigationbar和toolbar遮住上下区域，或者用闪亮的背景强调底部指示器区域。

上图为官方标准的黑色背景，注意不是纯黑色的，还能分辨传感器区域


三、SafeArea安全区域

安全区域是指在屏幕顶部和底部区域之间能正常显示内容的区域。顶部区域包括导航栏、状态栏或者传感器区域，底部区域包含Tabbar、工具栏或者home键指示器区域。

1、iPhoneX安全区域(全屏状态):

2、普通iPhone安全区域（包含所有状态）：



3、安全区域布局SafeAreaLayoutGuide

/* The top of the safeAreaLayoutGuide indicates the unobscured top edge of the view (e.g, not behind
 the status bar or navigation bar, if present). Similarly for the other edges.
 */
@property(nonatomic,readonly,strong) UILayoutGuide *safeAreaLayouGuide API_AVAILABLE(ios(11.0),tvos(11.0));

ContentView的布局为：

UIView *contentView = [[UIView alloc] initWithFrame:CGRectZero];
contentView.backgroundColor = [UIColor blueColor];
[self.view addSubview:contentView];

contentView.translatesAutoresizingMaskIntoConstraints = NO;//使用autolayout
NSLayoutConstraint *top = [view.topAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.topAnchor];
NSLayoutConstraint *bottom = [view.bottomAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.bottomAnchor];
NSLayoutConstraint *left = [view.leadingAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.leftAnchor];
NSLayoutConstraint *right = [view.trailingAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.rightAnchor];
[NSLayoutConstraint activateConstraints:@[left, right, top, bottom]];

注意safeAreaLayoutGuide只适用于iOS11，如果是之前的版本则必须用topLayoutGuide和bottomLayoutGuide。

ContentView的布局为：

NSLayoutConstraint *top = [NSLayoutConstraint constraintWithItem:contentView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.topLayoutGuide attribute:NSLayoutAttributeBottom multiplier:1 constant:0];
NSLayoutConstraint *bottom = [NSLayoutConstraint constraintWithItem:contentView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.bottomLayoutGuide attribute:NSLayoutAttributeTop multiplier:1 constant:0];
NSLayoutConstraint *left = [NSLayoutConstraint constraintWithItem:contentView attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeft multiplier:1 constant:0];
NSLayoutConstraint *right = [NSLayoutConstraint constraintWithItem:contentView attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeRight multiplier:1 constant:0];
[NSLayoutConstraint activateConstraints:@[top, bottom, left, right]];

如果你的App支持target最低版本号是iOS9，可以使用锚点布局NSLayoutAnchor：

NSLayoutConstraint *top = [contentView.topAnchor constraintEqualToAnchor:self.topLayoutGuide.bottomAnchor];
NSLayoutConstraint *bottom = [contentView.bottomAnchor constraintEqualToAnchor:self.bottomLayoutGuide.topAnchor];
NSLayoutConstraint *left = [contentView.leftAnchor constraintEqualToAnchor:self.view.leftAnchor];
NSLayoutConstraint *right = [contentView.rightAnchor constraintEqualToAnchor:self.view.rightAnchor];
[NSLayoutConstraint activateConstraints:@[top, bottom, left, right]];

另外safeAreaLayoutGuide是UView的属性，而topLayoutGuide和bottomLayoutGuide是UIViewController的属性。

如果想读取SafeArea的frame，可以读取属性view.safeAreaLayoutGuide.layoutFrame或者view.safeAreaInsets.
例如：

safeAreaInsets:{44, 0, 83, 0}
layoutFrame:{ {0, 44}, {375, 685}}

注意需要在UIView的layoutsubviews或者UIViewController的viewDidLayoutSubviews之后读取。

4、SafeArea Storyboard

如果是低版本创建的storyboard可以在inspector栏找到“Use Safe Area Layout Guides”勾选即可。

修改前：


修改后：


备注：storyboad配置向下兼容，低版本也可以使用。

四、布局适配

1、自定义导航栏

如果你的项目存在导航栏界面push到全屏界面，或者手势滑动做很炫的过场动画，那么你可能会用到自定义导航栏NavigationBar，每个ViewController维护自身的Navigationbar实例。

UINavigationBar *navigationBar = [[UINavigationBar alloc] initWithFrame:CGRectZero];
navigationBar.backgroundColor = [UIColor blueColor];
navigationBar.barTintColor = [UIColor blueColor];
navigationBar.titleTextAttributes = @{
    NSForegroundColorAttributeName:[UIColor whiteColor]};
navigationBar.items = @[[UINavigationItem new]];
navigationBar.topItem.title = self.title;
[self.view addSubview:navigationBar];

navigationBar.translatesAutoresizingMaskIntoConstraints = NO;

if (@available(iOS 11.0, *)) {
    NSLayoutConstraint *left = [navigationBar.leftAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.leftAnchor];
    NSLayoutConstraint *right = [navigationBar.rightAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.rightAnchor];
    NSLayoutConstraint *top = [navigationBar.topAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.topAnchor];
    NSLayoutConstraint *height = [navigationBar.heightAnchor constraintEqualToConstant:44];
    [NSLayoutConstraint activateConstraints:@[left, right, top, height]];
}else{
    NSLayoutConstraint *left = [navigationBar.leftAnchor constraintEqualToAnchor:self.view.leftAnchor];
    NSLayoutConstraint *right = [navigationBar.rightAnchor constraintEqualToAnchor:self.view.rightAnchor];
    NSLayoutConstraint *top = [navigationBar.topAnchor constraintEqualToAnchor:self.topLayoutGuide.bottomAnchor];
    NSLayoutConstraint *height = [navigationBar.heightAnchor constraintEqualToConstant:44];
    [NSLayoutConstraint activateConstraints:@[left, right, top, height]];
}



导航栏背景未扩展到状态栏，正常应该显示蓝色。

解决方案:

设置Navigationbar的UIBarPositioningDelegate返回UIBarPositionTopAttached即可。

typedef NS_ENUM(NSInteger, UIBarPosition) {
    UIBarPositionAny = 0,
    UIBarPositionBottom = 1, // The bar is at the bottom of its local context, and directional decoration draws accordingly (e.g., shadow above the bar).
    UIBarPositionTop = 2, // The bar is at the top of its local context, and directional decoration draws accordingly (e.g., shadow below the bar)
    UIBarPositionTopAttached = 3, // The bar is at the top of the screen (as well as its local context), and its background extends upward—currently only enough for the status bar.
} NS_ENUM_AVAILABLE_IOS(7_0);

navigationBar.delegate = self;

- (UIBarPosition)positionForBar:(id <UIBarPositioning>)bar
{
    return UIBarPositionTopAttached;
}

修改后正常显示了：

备注：navigationbar扩展到statusbar的颜色为barTintColor的值。如果失效，检查下是否将translucent设置为NO，并且Navigationbar必须为添加到ViewController的一级subView。
自定义导航栏后发现SafeArea没有变化,这样设置contentview的时候会将navigationbar遮挡。

safeAreaInsets:{44, 0, 34, 0}）

解决方案：设置additionalSafeAreaInsets

/* Custom container UIViewController subclasses can use this property to add to the overlay
 that UIViewController calculates for the safeAreaInsets for contained view controllers.
 */
@property(nonatomic) UIEdgeInsets additionalSafeAreaInsets API_AVAILABLE(ios(11.0), tvos(11.0));

设置该值后也要相应调整下导航栏的布局，之前是在SafeArea之内，现在要改为之外。

self.additionalSafeAreaInsets = UIEdgeInsetsMake(44, 0, 0, 0);
NSLayoutConstraint *left = [navigationBar.leftAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.leftAnchor];
NSLayoutConstraint *right = [navigationBar.rightAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.rightAnchor];
NSLayoutConstraint *bottom = [navigationBar.bottomAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.topAnchor];
NSLayoutConstraint *height = [navigationBar.heightAnchor constraintEqualToConstant:44];
[NSLayoutConstraint activateConstraints:@[left, right, bottom, height]];

可以看到安全区域也更新了:

safeAreaInsets:{88, 0, 34, 0}

2、自定义工具栏

可交互的固定组件是不能遮住home键指示器，需要放置在安全区域底部内。

CustomToolBar *toolbar = [[CustomToolBar alloc] initWithFrame:CGRectZero];
toolbar.backgroundColor = [UIColor blueColor];
[self.view addSubview:toolbar];

toolbar.translatesAutoresizingMaskIntoConstraints = NO;

if (@available(iOS 11.0, *)) {
    NSLayoutConstraint *bottom = [toolbar.bottomAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.bottomAnchor];
    NSLayoutConstraint *height = [toolbar.heightAnchor constraintEqualToConstant:48];
    NSLayoutConstraint *left = [toolbar.leftAnchor constraintEqualToAnchor:self.view.leftAnchor];
    NSLayoutConstraint *right = [toolbar.rightAnchor constraintEqualToAnchor:self.view.rightAnchor];
    [NSLayoutConstraint activateConstraints:@[bottom, height, left, right]];
}else{
    NSLayoutConstraint *bottom = [toolbar.bottomAnchor constraintEqualToAnchor:self.bottomLayoutGuide.topAnchor];
    NSLayoutConstraint *height = [toolbar.heightAnchor constraintEqualToConstant:48];
    NSLayoutConstraint *left = [toolbar.leftAnchor constraintEqualToAnchor:self.view.leftAnchor];
    NSLayoutConstraint *right = [toolbar.rightAnchor constraintEqualToAnchor:self.view.rightAnchor];
    [NSLayoutConstraint activateConstraints:@[bottom, height, left, right]];
}

放置在安全区域内导致Home键指示器区域背景留底了，怎么办？
解决方案：系统的UIToolBar会自动扩展背景颜色到底部，可以让Custombar继承UIToolBar，或者直接放置一个ToolBar的在底部当做背景也是可以的。注意高度不能超过48，否则失效。

UIToolbar *toolbar = [[UIToolbar alloc] initWithFrame:CGRectZero];
toolbar.backgroundColor = [UIColor blueColor];
toolbar.barTintColor = [UIColor blueColor];
[self.view addSubview:toolbar];

同样，你也可以设置additionalSafeAreaInsets，让安全区域限制在工具栏上方。

3、TableView布局

如果底部区域不存在可交互的固定组件，那么tableView需要延伸到屏幕底部。

if (@available(iOS 11.0, *)) {
    NSLayoutConstraint *top = [tableView.topAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.topAnchor];
    NSLayoutConstraint *bottom = [tableView.bottomAnchor constraintEqualToAnchor:self.view.bottomAnchor];
    NSLayoutConstraint *left = [tableView.leftAnchor constraintEqualToAnchor:self.view.leftAnchor];
    NSLayoutConstraint *right = [tableView.rightAnchor constraintEqualToAnchor:self.view.rightAnchor];
    [NSLayoutConstraint activateConstraints:@[top, bottom, left, right]];
} else {
    NSLayoutConstraint *top = [tableView.topAnchor constraintEqualToAnchor:self.topLayoutGuide.bottomAnchor];
    NSLayoutConstraint *bottom = [tableView.bottomAnchor constraintEqualToAnchor:self.view.bottomAnchor];
    NSLayoutConstraint *left = [tableView.leftAnchor constraintEqualToAnchor:self.view.leftAnchor];
    NSLayoutConstraint *right = [tableView.rightAnchor constraintEqualToAnchor:self.view.rightAnchor];
    [NSLayoutConstraint activateConstraints:@[top, bottom, left, right]];
}

尽管最后一个cell会被Home键指示器遮挡，将tableView向上滑动极限时，最后一个cell是显示在Home键指示器之上的。

4、横屏交互适配

主要涉及到视频播放的边缘交互按钮。

• 内容
  内容只需放置在SafeArea之内。同样底部如果没有固定可交互组件也要延伸到屏幕底部。
  
  

• 交互按钮
  屏幕角落边缘可交互按钮需要在SafeArea内部，并且还需再限制在layoutMargins之内(UIViewController属性)

/* -layoutMargins returns a set of insets from the edge of the view's bounds that denote a default spacing for laying out content.
If preservesSuperviewLayoutMargins is YES, margins cascade down the view tree, adjusting for geometry offsets, so that setting
the left value of layoutMargins on a superview will affect the left value of layoutMargins for subviews positioned close to the
left edge of their superview's bounds
 If your view subclass uses layoutMargins in its layout or drawing, override -layoutMarginsDidChange in order to refresh your 
view if the margins change.
 On iOS 11.0 and later, please support both user interface layout directions by setting the directionalLayoutMargins property
instead of the layoutMargins property. After setting the directionalLayoutMargins property, the values in the left and right
fields of the layoutMargins property will depend on the user interface layout direction.
*/
@property (nonatomic) UIEdgeInsets layoutMargins NS_AVAILABLE_IOS(8_0);

效果如下：


safeAreaInsets:{0, 44, 21, 44}
layoutMargins:{0, 64, 21, 64}

五、Home键指示器隐藏

一般情况只有视频全屏播放和游戏界面需要设置自动隐藏，API如下：


@interface UIViewController (UIHomeIndicatorAutoHidden)

// Override to return a child view controller or nil. If non-nil, that view controller's home indicator auto-hiding will be used. If nil, self is used. Whenever the return value changes, -setNeedsHomeIndicatorAutoHiddenUpdate should be called.
- (nullable UIViewController *)childViewControllerForHomeIndicatorAutoHidden API_AVAILABLE(ios(11.0)) API_UNAVAILABLE(watchos, tvos);

// Controls the application's preferred home indicator auto-hiding when this view controller is shown.
- (BOOL)prefersHomeIndicatorAutoHidden API_AVAILABLE(ios(11.0)) API_UNAVAILABLE(watchos, tvos);

// This should be called whenever the return values for the view controller's home indicator auto-hiding have changed.
- (void)setNeedsUpdateOfHomeIndicatorAutoHidden API_AVAILABLE(ios(11.0)) API_UNAVAILABLE(watchos, tvos);

@end

打开自动隐藏功能

- (BOOL)prefersHomeIndicatorAutoHidden
{
    return YES;
}

如果想手动控制隐藏功能，动态返回一个值，并且在更新的时候调用setNeedsUpdateOfHomeIndicatorAutoHidden。

- (BOOL)prefersHomeIndicatorAutoHidden
{
    return  _homeIndicatorAutoHidden;
}

_homeIndicatorAutoHidden = NO;
[self setNeedsUpdateOfHomeIndicatorAutoHidden];

六、屏幕边缘手势冲突

有时候你的App需要控制从状态栏下拉或者底部栏上滑，这个会跟系统的下拉通知中心手势和上滑控制中心手势冲突。
如果你要优先自己处理手势可以将系统手势延迟。

@interface UIViewController (UIScreenEdgesDeferringSystemGestures)

// Override to return a child view controller or nil. If non-nil, that view controller's screen edges deferring system gestures will be used. If nil, self is used. Whenever the return value changes, -setNeedsScreenEdgesDeferringSystemGesturesUpdate should be called.
- (nullable UIViewController *)childViewControllerForScreenEdgesDeferringSystemGestures API_AVAILABLE(ios(11.0)) API_UNAVAILABLE(watchos, tvos);

// Controls the application's preferred screen edges deferring system gestures when this view controller is shown. Default is UIRectEdgeNone.
- (UIRectEdge)preferredScreenEdgesDeferringSystemGestures API_AVAILABLE(ios(11.0)) API_UNAVAILABLE(watchos, tvos);

// This should be called whenever the return values for the view controller's screen edges deferring system gestures have changed.
- (void)setNeedsUpdateOfScreenEdgesDeferringSystemGestures API_AVAILABLE(ios(11.0)) API_UNAVAILABLE(watchos, tvos);

@end

例如：

- (UIRectEdge)preferredScreenEdgesDeferringSystemGestures
{
    return UIRectEdgeTop;
}

设置后下拉状态栏只会展示指示器，继续下拉才能将通知中心拉出来。如果返回UIRectEdgeNone则会直接下拉出来。

七、开源库Masonry更新SafeArea支持

想必有不少开发受够了苹果Autolayout繁琐的API调用，Mansonry的出现完美解决了这一大痛点。

比如原生代码调用：

NSLayoutConstraint *top = [NSLayoutConstraint constraintWithItem:contentView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1 constant:0];
NSLayoutConstraint *bottom = [NSLayoutConstraint constraintWithItem:contentView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeBottom multiplier:1 constant:0];
NSLayoutConstraint *left = [NSLayoutConstraint constraintWithItem:contentView attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeft multiplier:1 constant:0];
NSLayoutConstraint *right = [NSLayoutConstraint constraintWithItem:contentView attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeRight multiplier:1 constant:0];
[NSLayoutConstraint activateConstraints:@[top, bottom, left, right]];

使用masonry后：

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

代码简洁高下立判。

支持SafeArea需要更新到V1.1.0版本

适配代码示例：

• 原生代码：

  if (@available(iOS 11.0, *)) {
  NSLayoutConstraint *top = [contentView.topAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.topAnchor];
  NSLayoutConstraint *bottom = [contentView.bottomAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.bottomAnchor];
  NSLayoutConstraint *left = [contentView.leftAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.leftAnchor];
  NSLayoutConstraint *right = [contentView.rightAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.rightAnchor];
  [NSLayoutConstraint activateConstraints:@[top, bottom, left, right]];
  } else {
  NSLayoutConstraint *top = [contentView.topAnchor constraintEqualToAnchor:self.topLayoutGuide.bottomAnchor];
  NSLayoutConstraint *bottom = [contentView.bottomAnchor constraintEqualToAnchor:self.bottomLayoutGuide.topAnchor];
  NSLayoutConstraint *left = [contentView.leftAnchor constraintEqualToAnchor:self.view.leftAnchor];
  NSLayoutConstraint *right = [contentView.rightAnchor constraintEqualToAnchor:self.view.rightAnchor];
  [NSLayoutConstraint activateConstraints:@[top, bottom, left, right]];
  }
  

  使用Masonry代码：

  [contentView mas_makeConstraints:^(MASConstraintMaker *make) {
  if (@available(iOS 11.0, *)) {
      make.top.equalTo(self.view.mas_safeAreaLayoutGuideTop);
      make.bottom.equalTo(self.view.mas_safeAreaLayoutGuideBottom);
      make.left.equalTo(self.view.mas_safeAreaLayoutGuideLeft);
      make.right.equalTo(self.view.mas_safeAreaLayoutGuideRight);
  }else{
      make.top.equalTo(self.mas_topLayoutGuideBottom);
      make.bottom.equalTo(self.mas_bottomLayoutGuideTop);
      make.left.equalTo(self.view);
      make.right.equalTo(self.view);
  }
  }];
  

参考教程：

1、Human Interface Guidelines

2、Designing for iPhone X

3、Building Apps for iPhone X

4、原文链接

- (instancetype)initWithFrame:(CGRect)frame
{
    //ios11 新增的UIToolbarContentView移到自定义控件之下
    self = [super initWithFrame:frame];
    if (self) {
        [self layoutIfNeeded];
        self.backgroundColor = [UIColor greenColor];
        self.barTintColor = [UIColor yellowColor];

        [self addSubview:self.button];
    }
    return self;
}