Question

我试图设置我的项目而不使用xcode中的故事板和目标c。

我的appDelegate：

·H

#import <UIKit/UIKit.h>
#import "ViewController.h"

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@end

的.m

#import "AppDelegate.h"

@interface AppDelegate ()

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    ViewController *vc = [[ViewController alloc] init];
    self.window.rootViewController = vc;
    return YES;
}

etc...

我的viewController文件：

的.m

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    UIView *view = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    view.backgroundColor = [UIColor redColor];
    [self.view addSubview:view];

}

我认为我的代码是正确的，我运行它时应该有一个红色的屏幕，但我只得到一个黑屏。有人能告诉我，我是否忘记了某些事情，或者是否与项目设置有关。感谢。

Answer 1

添加

self.window = [[UIWindow alloc] initWithFrame:UIScreen.mainScreen.bounds];

到application:didFinishLaunchingWithOptions:

Answer 2

你错过了两个步骤。

初始化窗口：

self.window = [[UIWindow alloc] initWithFrame:UIScreen.mainScreen.bounds];

制作窗口键＆amp;可见：
```
[self.window makeKeyAndVisible];
```

总而言之，您的代码应该如下所示：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    // Initialize the window
    self.window = [[UIWindow alloc] initWithFrame:UIScreen.mainScreen.bounds]; 

    // Add the view controller to the window
    ViewController *vc = [[ViewController alloc] init];
    self.window.rootViewController = vc;

    // Make window key & visible
    [self.window makeKeyAndVisible];

    return YES;
}

以编程方式设置视图

2 个答案: