應用程式主NSMenu在沒有重新激活視窗的情況下沒有回應

我正在嘗試使用代碼在本頁中描述的簡約 Cocoa 應用程式 ：

#import <Cocoa/Cocoa.h>;
int main ()
{
    [NSAutoreleasePool new];
    [NSApplication sharedApplication];
    [NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
    id menubar = [[NSMenu new] autorelease];
    id appMenuItem = [[NSMenuItem new] autorelease];
    [menubar addItem:appMenuItem];
    [NSApp setMainMenu:menubar];
    id appMenu = [[NSMenu new] autorelease];
    id appName = [[NSProcessInfo processInfo] processName];
    id quitTitle = [@"Quit " stringByAppendingString:appName];
    id quitMenuItem = [[[NSMenuItem alloc] initWithTitle:quitTitle
        action:@selector(terminate:) keyEquivalent:@"q"] autorelease];
    [appMenu addItem:quitMenuItem];
    [appMenuItem setSubmenu:appMenu];
    id window = [[[NSWindow alloc] initWithContentRect:NSMakeRect(0, 0, 200, 200)
        styleMask:NSTitledWindowMask backing:NSBackingStoreBuffered defer:NO]
            autorelease];
    [window cascadeTopLeftFromPoint:NSMakePoint(20,20)];
    [window setTitle:appName];
    [window makeKeyAndOrderFront:nil];
    [NSApp activateIgnoringOtherApps:YES];
    [NSApp run];
    return 0;
}

我的問題是，應用程式選單在我重新激活其視窗（激活另一個應用程式，然后單擊回傳我的應用程式視窗）之前沒有回應。

知道為什么以及如何解決它嗎？

uj5u.com熱心網友回復：

當您嘗試呼叫時，AppKit 仍處于應用的啟動階段[NSApp activateIgnoringOtherApps:YES];。正確的方法是通過以下方式處理它NSApplicationDelegate：

@interface AppDelegate : NSObject <NSApplicationDelegate>
@property (strong, nonatomic, class, readonly) AppDelegate* sharedInstance;
@end
@implementation AppDelegate
  (instancetype)sharedInstance {
    static AppDelegate *sharedInstance = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sharedInstance = [AppDelegate new];
    });
    return sharedInstance;
}
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
    [NSApp activateIgnoringOtherApps:YES];
}
@end

int main ()
{
    [NSAutoreleasePool new];
    [NSApplication sharedApplication];
    NSApplication.sharedApplication.delegate = [AppDelegate sharedInstance];
    [NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
    id menubar = [[NSMenu new] autorelease];
    id appMenuItem = [[NSMenuItem new] autorelease];
    [menubar addItem:appMenuItem];
    [NSApp setMainMenu:menubar];
    id appMenu = [[NSMenu new] autorelease];
    id appName = [[NSProcessInfo processInfo] processName];
    id quitTitle = [@"Quit " stringByAppendingString:appName];
    id quitMenuItem = [[[NSMenuItem alloc] initWithTitle:quitTitle
        action:@selector(terminate:) keyEquivalent:@"q"] autorelease];
    [appMenu addItem:quitMenuItem];
    [appMenuItem setSubmenu:appMenu];
    id window = [[[NSWindow alloc] initWithContentRect:NSMakeRect(0, 0, 200, 200)
        styleMask:NSTitledWindowMask backing:NSBackingStoreBuffered defer:NO]
            autorelease];
    [window cascadeTopLeftFromPoint:NSMakePoint(20,20)];
    [window setTitle:appName];
    [window makeKeyAndOrderFront:nil];
    [NSApp run];
    return 0;
} 

作為獎勵，委托- (void)applicationDidFinishLaunching:(NSNotification *)aNotification { 將在您之前被呼叫：

dispatch_async(dispatch_get_main_queue(), ^{
    [NSApp activateIgnoringOtherApps:YES];
});

暗示這是正確的做法。

uj5u.com熱心網友回復：

好的...我找到了解決方案...我必須更換

    [NSApp activateIgnoringOtherApps:YES];

和：

    dispatch_async(dispatch_get_main_queue(), ^{
        [NSApp activateIgnoringOtherApps:YES];
    });

我不知道為什么，但它有效。

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