1

みなさん、良い一日を、

Storyboard を使用している場合、ViewController でメソッド refresh を呼び出すことができません。ただし、ストーリーボードなしで NIB だけでプロジェクトを作成すると機能します。うまくいかない理由と、この問題を解決する方法は?

これが私のコードです：

AppDelegate.h

#import <UIKit/UIKit.h>

@class ViewController;


@interface AppDelegate : NSObject <UIApplicationDelegate>
{
    UIWindow *window;
    ViewController *viewController;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet ViewController *viewController;

@end

AppDelegate.m

#import "AppDelegate.h"
#import "ViewController.h"

@implementation AppDelegate

@synthesize window;
@synthesize viewController;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    return YES;
}

- (void)applicationWillResignActive:(UIApplication *)application
{
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
    NSLog(@"app will enter foreground");
    [viewController refresh:NULL]; 
}

- (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
{
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}

@end

ViewController.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

-(IBAction) refresh:(id)sender;

@end

ViewController.m

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

- (void)loadData {
    // contains information the ViewController makes use of
}

-(IBAction)refresh:(id) sender {
    [self loadData];
}

@end
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1 に答える 1

2

viewControllerストーリーボードを使用する場合、アプリ デリゲートのプロパティは設定されません。確認のためにログ ステートメントに値を含めます。値は null になります。

代わりに、通知用にビュー コントローラーを登録し、独自の更新を処理させます。

ビューでDidLoad:

[super viewDidLoad];
[[NSNotificationCenter defaultCenter] addObserver:self 
    selector:@selector(refresh:) 
    name:UIApplicationDidBecomeActiveNotification
    object: nil];

dealloc / viewDidUnload でもこのオブザーバーを削除する必要があります。

于 2012-07-17T06:05:48.213 に答える