xcode 如何正确创建根视图控制器？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/7782796/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to properly create a root view controller?
提问by user278859
After upgrading to xCode 4.2 I am getting the following warning...
升级到 xCode 4.2 后，我收到以下警告...
Applications are expected to have a root view controller at the end of application launch
应用程序应该在应用程序启动结束时有一个根视图控制器
After reading as much as I could find on line about the RootViewController I am not sure whether I have created my root view controller properly. I created it a long time ago when I was first learning to program in xCode.
在阅读了我在网上能找到的关于 RootViewController 的尽可能多的内容后，我不确定我是否正确地创建了我的根视图控制器。很久以前，当我第一次学习在 xCode 中编程时，我就创建了它。
One question I have is it ok to name the root view controller something other than RootViewController. Every example I see now has it named RootViewController. I also see it synthesized in the app delegate like this...
我的一个问题是可以将根视图控制器命名为 RootViewController 以外的其他名称。我现在看到的每个示例都将其命名为 RootViewController。我也看到它像这样在应用程序委托中合成......
@synthesize rootViewController = _rootViewController;
I do not understand what this is doing. Why not just...
我不明白这是在做什么。为什么不只是...
@synthesize rootViewController;
In any event I changed the name of my root view controller to RootViewController and followed the example I found at cupsofcocoa.com. But even after the changes I am still getting the "...expected to have a root controller..." warning.
无论如何，我将根视图控制器的名称更改为 RootViewController 并遵循我在cupsofcocoa.com 上找到的示例。但即使在更改之后，我仍然收到“......预计有一个根控制器......”警告。
If someone has the time to take a look and let me know what I am missing, I have listed the the significant portions of my initialization code below.
如果有人有时间看一看并让我知道我遗漏了什么，我已经在下面列出了我的初始化代码的重要部分。
Thanks,
谢谢，
John
约翰
//RootViewController.h
#import <UIKit/UIKit.h>
@interface RootViewController : UIViewController {
}
@end
.
.
//RootViewController.m
#import "RootViewController.h"
#import "JetLoggerAppDelegate.h"
@implementation RootViewController
@end
.
.
//JetLoggerAppDelegate.h my app delegate
#import <UIKit/UIKit.h>
@class RootViewController;
@interface JetLoggerAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
RootViewController *rootViewController;
}
@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet RootViewController *rootViewController;
@end
.
.
//.m app delegate
#import "JetLoggerAppDelegate.h"
#import "RootViewController.h" //I don't think I need this here
@implementation JetLoggerAppDelegate
@synthesize window;
@synthesize rootViewController = _rootViewController;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
if ([launchOptions count] == 0) {
_rootViewController = [[RootViewController alloc] init];
self.window.rootViewController = self.rootViewController;
[window makeKeyAndVisible];
return YES;
}else{
[JLHelper showAlertWithTitle:@"" message:[NSString stringWithFormat:@"launchOptions: %@", launchOptions]];
}
return NO;
}
.
.
//main.m
#import <UIKit/UIKit.h>
int main(int argc, char *argv[]) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int retVal = UIApplicationMain(argc, argv, nil, @"JetLoggerAppDelegate");
[pool release];
return retVal;
}
回答by donjordano
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
if ([launchOptions count] == 0) {
_rootViewController = [[RootViewController alloc] init];
self.window.rootViewController = self.rootViewController;
**[window addSubview:_rootViewController.view];**
[window makeKeyAndVisible];
return YES;
}else{
[JLHelper showAlertWithTitle:@"" message:[NSString stringWithFormat:@"launchOptions: %@", launchOptions]];
return NO;
}
return nil;
}
Put return NO inside else statement and on the end put return nil; Hope this help.
把 return NO 放在 else 语句中，最后把 return nil; 希望这有帮助。
回答by jeet.chanchawat
Applications are expected to have a root view controller
应用程序应该有一个根视图控制器
Replace in AppDelegate
在 AppDelegate 中替换
[window addSubview:[someController view]];
to
到
[self.window setRootViewController:someController];
