如何解决Objective-C程序标题未显示
我已在ViewController.m中设置了self.navigationItem.title = @"Hello";
,但未显示:
AppDelegate.m
#import "AppDelegate.h"
#import "ViewController.h"
@interface AppDelegate ()
@end
@implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
self.window = [[UIWindow alloc] initWithFrame:UIScreen.mainScreen.bounds];
ViewController *viewController = [[ViewController alloc] init];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:viewController];
self.window.rootViewController = navController;
[self.window makeKeyAndVisible];
return YES;
}
#pragma mark - UIScenesession lifecycle
- (UISceneConfiguration *)application:(UIApplication *)application configurationForConnectingScenesession:(UIScenesession *)connectingScenesession options:(UISceneConnectionoptions *)options API_AVAILABLE(ios(13.0)) {
// Called when a new scene session is being created.
// Use this method to select a configuration to create the new scene with.
return [[UISceneConfiguration alloc] initWithName:@"Default Configuration" sessionRole:connectingScenesession.role];
}
- (void)application:(UIApplication *)application diddiscardScenesessions:(NSSet<UIScenesession *> *)scenesessions API_AVAILABLE(ios(13.0)) {
// Called when the user discards a scene session.
// If any sessions were discarded while the application was not running,this will be called shortly after application:didFinishLaunchingWithOptions.
// Use this method to release any resources that were specific to the discarded scenes,as they will not return.
}
@end
ViewController.m
#import "ViewController.h"
#import <UIKit/UIKit.h>
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.navigationItem.title = @"Hello";
self.view.backgroundColor = [UIColor systemBlueColor];
}
@end
谢谢!
解决方法
我正在考虑您不使用情节提要。 就您而言,您必须以编程方式执行所有操作,包括分配导航栏。
- (void)viewDidLoad {
[super viewDidLoad];
UINavigationBar *navbar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0,20,self.view.frame.size.width,44)];
UINavigationItem *title = [[UINavigationItem alloc] initWithTitle:@"Hello"];
self.view.backgroundColor = [UIColor systemBlueColor];
[navbar setItems:@[title]];
[self.view addSubview:navbar];
}
如果您使用情节提要,则此简单命令将起作用,而无需在appDelegate中进行任何操作。
self.navigationItem.title = @"Hello";
,
只需说:viewController.title = @“Hello”;
https://developer.apple.com/documentation/uikit/uiviewcontroller/1621364-title
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