不能返回firstResponder狀態

Question

已經建立了我的appDelegate以返回firstResponder狀態，但是當我編譯（它編譯好）時，控制檯返回「無法成爲第一響應者」，但沒有說明原因。

我附上了代碼。你能告訴我什麼是錯的嗎？提前致謝。

HypnosisterAppDelegate.m

#import "HypnosisterAppDelegate.h" 
#import "HypnosisView.h" 

@implementation HypnosisterAppDelegate 

@synthesize window = _window; 

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{ 
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
    // Override point for customization after application launch. 

    HypnosisView *view = [[HypnosisView alloc] initWithFrame:[[self window]bounds]]; 
    [[self window]addSubview:view]; 

    BOOL success = [view becomeFirstResponder]; 
    if (success) { 
    NSLog(@"HypnosisView became the first responder"); 
    } else { 
    NSLog(@"Could not become the first responder"); 
    } 

    self.window.backgroundColor = [UIColor whiteColor]; 
    [self.window makeKeyAndVisible]; 
    return YES; 
} 

-(BOOL)canBecomeFirstResponder 
{ 
    return YES; 
} 

Answer 1

你已經實現canBecomeFirstResponder上HypnosisterAppDelegate，這是不是一個UIResponder子類。然後，您將becomeFirstResponder發送到您的自定義視圖（HypnosisView）。

HypnosisView（不是HypnosisterAppDelegate）需要做到這一點：

-(BOOL)canBecomeFirstResponder 
{ 
    return YES; 
}