不能返回firstResponder状态

Question

已经建立了我的appDelegate以返回firstResponder状态，但是当我编译（它编译好）时，控制台返回“无法成为第一响应者”，但没有说明原因。

我附上了代码。你能告诉我什么是错的吗？提前致谢。

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

你已经实现canBecomeFirstResponder上HypnosisterAppDelegate，这是不是一个UIResponder子类。然后，您将becomeFirstResponder发送到您的自定义视图（HypnosisView）。

HypnosisView（不是HypnosisterAppDelegate）需要做到这一点：

-(BOOL)canBecomeFirstResponder 
{ 
    return YES; 
}