[移动开发]iOS 15 适配总结

Xcode 13.0 编译问题

一些老项目使用的编译方式是 Legacy Build System (Deprecated)。这个方式在 Xcode 13.0中会报编译错误。

: The Legacy Build System will be removed in a future release. You can configure the selected build system and this deprecation message in File > Workspace Settings.

解决方案：

• 菜单栏 File -> Workspace Settings -> BuildSystem
• 上面选择使用 New Build System (Default)
• 下面选择使用 Legacy Build System (Deprecated)
• 勾选 Do not show a diagnostic issue about build system deprecation 即可

UITabbar及UINavigationBar的背景颜色问题

从iOS 14升级到 iOS 15会出现 导航栏背景颜色失效

原因是设置颜色的方法在iOS 15中失效了

在iOS 13更新的API中分别新增了针对navigationBar、tabbar设置属性，这些属性包括滑动的时候产生的颜色、透明等等信息，曾经的设置信息在iOS 14以前的版本中还可以使用UINavigationBarAppearance 和 UITabBarAppearance进行设置，但是在iOS 15上被禁用，因此，你需要做如下修改

if (@available(iOS 15, *)) {
	// 设置 TabBar
	UITabBarAppearance *appearance = [[UITabBarAppearance alloc] init];
	//tabBaritem title选中状态颜色
	appearance.stackedLayoutAppearance.selected.titleTextAttributes = @{
    NSForegroundColorAttributeName: [UIColor blueColor]};
	//tabBaritem title未选中状态颜色
	appearance.stackedLayoutAppearance.normal.titleTextAttributes = @{
    NSForegroundColorAttributeName: [UIColor blueColor]};
	//tabBar背景颜色
	appearance.backgroundColor = [UIColor blackColor];
	self.tabBarItem.scrollEdgeAppearance = appearance;
	self.tabBarItem.standardAppearance = appearance;
	
	// 设置 NavigationBar
	UINavigationBarAppearance *appearance = [[UINavigationBarAppearance alloc] init];
	appearance.backgroundColor = [UIColor blackColor];
	self.navigationBar.standardAppearance = appearance;
	self.navigationBar.scrollEdgeAppearance = appearance;
} else {
	//设置navigationBar颜色
	self.navigationController.navigationBar.barTintColor = [UIColor blueColor];
	
	// 设置tabBar背景色
	self.tabBarController.tabBar.backgroundColor = [UIColor blueColor];
	// 设置tabBarItem字体颜色
	NSMutableDictionary<NSAttributedStringKey, id> *normalAttributes =[NSMutableDictionary dictionary];
	[normalAttributes setValue:[UIColor blueColor] forKey:NSForegroundColorAttributeName];

	[self.tabBarItem setTitleTextAttributes:normalAttributes.copy forState:UIControlStateNormal];
	[self.tabBarItem setTitleTextAttributes:normalAttributes.copy forState:UIControlStateSelected];
}

其中 standardAppearance 和 scrollEdgeAppearance 的区别

• standardAppearance — 常规状态
• scrollEdgeAppearance — 小屏幕手机横屏时的状态或滚动状态

UITableView 新属性

sectionHeaderTopPadding

官方文档

/// Determines if the table view allows its cells to become focused.
/// When tableView:canFocusRowAtIndexPath: is implemented, its return value takes precedence over this method.
/// Defaults to a system derived value based on platform and other properties of the table view.
@property (nonatomic, getter=isPrefetchingEnabled) BOOL prefetchingEnabled

/// iOS 15中 tableView 会给每一个 section 的顶部（header以上）再加上一个 22像素 的高度，形成一个 section 和 section 之间的间距

使用

// 为了配合以前的开发习惯，我们只需要在创建实例的时候进行对间距的设置即可

if (@available(iOS 15.0, *)) {
    tableView.sectionHeaderTopPadding = 0;
} 

// 或者全局设置

if (@available(iOS 15.0, *)) {
    [UITableView appearance].sectionHeaderTopPadding = 0;
}

增加 UISheetPresentationController

新增 UISheetPresentationController，通过它可以控制 Modal 出来的 UIViewController 的显示大小，且可以通过拖拽手势在不同大小之间进行切换，只需要在跳转的目标 UIViewController 中做如下处理

if (@available(iOS 15.0, *)) {
    if (self.sheetPresentationController) {
        // 显示支持的尺寸
        self.sheetPresentationController.detents = @[UISheetPresentationControllerDetentIdentifierMedium, UISheetPresentationControllerDetentIdentifierLarge];
        // 显示一个指定器表示可以拖拽调整大小
        self.sheetPresentationController.prefersGrabberVisible = true;
    }
}

UIButton 支持更多配置

UIButton.Configuration 是一个新的属性，它指定按钮及其内容的外观和行为。它有许多与按钮外观和内容相关的属性。如 cornerStyle、buttonSize、macIdiomStyle、baseForegroundColor、image、imageColorTransformer、preferredSymbolConfigurationForImage等等

if (@available(iOS 15.0, *)) {
    // Plain
    UIButton *plain = [UIButton buttonWithConfiguration:[UIButtonConfiguration plainButtonConfiguration] primaryAction:nil];
     plain setTitle:@"Plain" forState:UIControlStateNormal];
        
    // Gray
    UIButton *gray = [UIButton buttonWithConfiguration:[UIButtonConfiguration grayButtonConfiguration] primaryAction:nil];
    [gray setTitle:@"Gray" forState:UIControlStateNormal];
        
    // Tinted
    UIButton *tinted = [UIButton buttonWithConfiguration:[UIButtonConfiguration tintedButtonConfiguration] primaryAction:nil];
    [tinted setTitle:@"Tinted" forState:UIControlStateNormal];
        
    // Filled
    UIButton *filled = [UIButton buttonWithConfiguration:[UIButtonConfiguration tintedButtonConfiguration] primaryAction:nil];
    [filled setTitle:@"Filled" forState:UIControlStateNormal];
}

CLLocationButton

推出CLLocationButton 用于一次性定位授权，该内容内置于 CoreLocationUI 模块，但是如果需要获取定位的详细信息，仍然需要借助于 CoreLocation。

#import <CoreLocationUI/CoreLocationUI.h>

CLLocationButton *locationButton = [[CLLocationButton alloc] init];
// 文字
locationButton.label = CLLocationButtonLabelCurrentLocation;
locationButton.fontSize = 20;
// 图标
locationButton.icon = CLLocationButtonIconArrowFilled;
// 圆角
locationButton.cornerRadius = 10;
// tint
locationButton.tintColor = [UIColor systemPinkColor];
// 背景色
locationButton.backgroundColor = [UIColor systemGreenColor];
// 点击事件，应该在其方法中发起定位请求
[locationButton addTarget:self action:@selector(getCurrentLocation) forControlEvents:UIControlEventTouchUpInside];

async/await Swift 专有

URLSession 推出支持 async/await 的 API，包括获取数据、上传与下载

// 加载数据
let (data, response) = try await URLSession.shared.data(from: url)
// 下载
let (localURL, _) = try await session.download(from: url)
// 上传
let (_, response) = try await session.upload(for: request, from: data)

系统图片支持多个层，支持多种渲染模式

// hierarchicalColor: 多层渲染，透明度不同
UIImageConfiguration *config = [UIImageSymbolConfiguration configurationWithHierarchicalColor:[UIColor systemRedColor]];
UIImage *image = [UIImage systemImageNamed:@"square.stack.3d.down.right.fill" withConfiguration:config];

// paletteColors: 多层渲染，设置不同风格
UIImageConfiguration *config2 = [UIImageSymbolConfiguration configurationWithPaletteColors:@[[UIColor systemRedColor], [UIColor systemGreenColor], [UIColor systemBlueColor]]];
UIImage *image2 = [UIImage systemImageNamed:@"person.3.sequence.fill" withConfiguration:config2];

// hierarchicalColor：多层渲染，透明度不同
let config = UIImage.SymbolConfiguration(hierarchicalColor: .systemRed)
let image = UIImage(systemName: "square.stack.3d.down.right.fill", withConfiguration: config)

// paletteColors：多层渲染，设置不同风格
let config2 = UIImage.SymbolConfiguration(paletteColors: [.systemRed, .systemGreen, .systemBlue])
let image2 = UIImage(systemName: "person.3.sequence.fill", withConfiguration: config2)

UIImage 新增调整尺寸的方法

// buPreparingThumbnail
[[UIImage imageNamed:@"sv.png"] imageByPreparingThumbnailOfSize:CGSizeMake(200, 100)];
// prepareThumbnail, block中直接获取调整后的UIImage
[[UIImage imageNamed:@"sv.png"] prepareThumbnailOfSize:CGSizeMake(200, 100) completionHandler:^(UIImage * _Nullable image) {
   // 需要回到主线程更新UI
}];

// preparingThumbnail
UIImage(named: "sv.png")?.preparingThumbnail(of: CGSize(width: 200, height: 100))
// prepareThumbnail，闭包中直接获取调整后的UIImage
UIImage(named: "sv.png")?.prepareThumbnail(of: CGSize(width: 200, height: 100)) { image in
    // 需要回到主线程更新UI
}
// byPreparingThumbnail
await UIImage(named: "sv.png")?.byPreparingThumbnail(ofSize: CGSize(width: 100, height: 100))

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