IOS被遗忘的知识

IOS ARC项目使用非ARC文件

1.自己的旧项目没有使用ARC，可是引入的第三方库却是使用了ARC的。对于第一个情况，给採用了ARC的源文件，加入-fobjc-arc选项2.自己的新项目使用了ARC，可是引入的第三方库或者曾经写的代码却没有使用ARC。对于另外一种情况，加入-fno-objc-arc改动NavigationController的后退button标题A push到B 。改动B的返回标题仅仅要在A中加入以下的代码

<span style="font-size:18px;">UIBarButtonItem *backItem = [[UIBarButtonItem alloc] init];
backItem.title = @"返回";
self.navigationItem.backBarButtonItem = backItem;</span>

- (instancetype)initWithNavigationBarClass:(Class)navigationBarClass toolbarClass:(Class)toolbarClassNS_AVAILABLE_IOS(5_0);

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];

UINavigationController *navigationController = [[UINavigationController alloc] initWithNavigationBarClass:[CRGradientNavigationBar class] toolbarClass:nil];

UIColor *firstColor = [UIColor colorWithRed:255.0f/255.0f green:42.0f/255.0f blue:104.0f/255.0f alpha:1.0f];
UIColor *secondColor = [UIColor colorWithRed:255.0f/255.0f green:90.0f/255.0f blue:58.0f/255.0f alpha:1.0f];

NSArray *colors = [NSArray arrayWithObjects:(id)firstColor.CGColor, (id)secondColor.CGColor, nil];
//NSArray *colors = [NSArray arrayWithObjects:(id)UIColorFromRGB(0xf16149).CGColor, (id)UIColorFromRGB(0xf14959).CGColor, nil];

[[CRGradientNavigationBar appearance] setBarTintGradientColors:colors];
[[navigationController navigationBar] setTranslucent:NO]; // Remember, the default value is YES.

DemoViewController *viewController = [[DemoViewController alloc] init];
[navigationController setViewControllers:@[viewController]];

[self.window setRootViewController:navigationController];

self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}