Question

我正在阅读一本书（Big Nerd Ranch IOS Programming），我正在使用的xcode版本比本书使用的版本略高。因此，我无法完全遵循书籍步骤，其中一个步骤是创建基于窗口的应用程序。

我做的是：我创建了一个空项目，它给了我代表和一些其他文件。我创建了自己的MainWindow.xib。

我一直在阅读，我正处于需要编译的部分，我应该在模拟器上看到一些东西。但是，我没有看到任何东西。我知道我在这里遗漏了一些东西，因为我猜我没有用代码（??）正确连接MainWindow.xib。请注意，本书告诉我将地图视图，文本字段和活动指示符添加到主窗口。

我想知道从头开始项目的正确方法是什么。我实际上更喜欢这样做，以便我可以获得启动ios项目的低谷。

更新在我将Info.plist“主nib文件基本名称”设置为“MainWindow”之后。我能够看到这个观点。但是，我无法单击模拟器上的文本字段并显示键盘。我点击了主页按钮，当我再次尝试点击该图标时，它会显示白色屏幕而不是带有文本字段的地图。

WhereamiAppDelegate.h

#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>
#import <MapKit/MapKit.h>

@interface WhereamiAppDelegate : UIResponder <UIApplicationDelegate, CLLocationManagerDelegate>{
    CLLocationManager * locationManager;
    IBOutlet MKMapView *worldView;
    IBOutlet UIActivityIndicatorView *activityIndicator;
    IBOutlet UITextField *locationTitleField;
}

@property (strong, nonatomic) IBOutlet UIWindow *window;

@property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;
@property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;
@property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;

- (void)saveContext;
- (NSURL *)applicationDocumentsDirectory;

@end

WhereamiAppDelegate.m

#import "WhereamiAppDelegate.h"

@implementation WhereamiAppDelegate

@synthesize window = _window;
@synthesize managedObjectContext = __managedObjectContext;
@synthesize managedObjectModel = __managedObjectModel;
@synthesize persistentStoreCoordinator = __persistentStoreCoordinator;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    locationManager = [[CLLocationManager alloc] init];

    [locationManager setDelegate:self];
    [locationManager setDistanceFilter:kCLDistanceFilterNone];
    [locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
    [locationManager startUpdatingLocation];

    [worldView setShowsUserLocation:YES];


    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];    
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];

    return YES;
}

- (void) locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation{
    NSLog(@"%@", newLocation);
}

- (void) locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error{
    NSLog(@"Could not find location: %@", error);
}

- (void)applicationWillResignActive:(UIApplication *)application
{

}

- (void)applicationDidEnterBackground:(UIApplication *)application
{
}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
    /*
     Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
     */
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    /*
     Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
     */
}

- (void)applicationWillTerminate:(UIApplication *)application
{
    // Saves changes in the application's managed object context before the application terminates.
    [self saveContext];
}

- (void)saveContext
{
    NSError *error = nil;
    NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
    if (managedObjectContext != nil)
    {
        if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error])
        {
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
        } 
    }
}

#pragma mark - Core Data stack

- (NSManagedObjectContext *)managedObjectContext
{
    if (__managedObjectContext != nil)
    {
        return __managedObjectContext;
    }

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (coordinator != nil)
    {
        __managedObjectContext = [[NSManagedObjectContext alloc] init];
        [__managedObjectContext setPersistentStoreCoordinator:coordinator];
    }
    return __managedObjectContext;
}

- (NSManagedObjectModel *)managedObjectModel
{
    if (__managedObjectModel != nil)
    {
        return __managedObjectModel;
    }
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"whereami" withExtension:@"momd"];
    __managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
    return __managedObjectModel;
}

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    if (__persistentStoreCoordinator != nil)
    {
        return __persistentStoreCoordinator;
    }

    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"whereami.sqlite"];

    NSError *error = nil;
    __persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error])
    {
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }    

    return __persistentStoreCoordinator;
}

#pragma mark - Application's Documents directory

- (NSURL *)applicationDocumentsDirectory
{
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}

@end

的main.m

#import <UIKit/UIKit.h>

#import "WhereamiAppDelegate.h"

int main(int argc, char *argv[])
{
    @autoreleasepool {
        return UIApplicationMain(argc, argv, nil, NSStringFromClass([WhereamiAppDelegate class]));
    }
}

info.plist

MainWindow.xib

Answer 1

请参阅here（引自@WrightCS）：

MainWindow.xib是在info.plist中定义为主nib文件基本名称。在MainWindow.xib中，定义第一个控制器你要加载的是RootViewController。

Answer 2

检查您的main.m文件（假设您有一个 - 如果没有，这是您问题的一部分）。你可能会看到这样的一行：

int retVal = UIApplicationMain(argc, argv, nil, nil);

为了让你的应用做任何事情，它应该是这样的：

int retVal = UIApplicationMain(argc, argv, @"UIApplication", @"MyAppDelegate");

假设您的项目中有MyAppDelegate.h和MyAppDelegate.m。

从Scratch启动Xcode Project并且无法显示任何内容

2 个答案: