主while循环没有得到全局变量的当前值

我有一个Xcode 5 /可可程序，指定的时间间隔后点击鼠标左键指定的次数。这部分工作正常。当我想要提前停止while循环时会出现问题。主while循环没有得到全局变量的当前值

我正在使用监听程序在程序运行期间检测到任何按键，设置一个stopnow变量并检查while loop中的变量。但是，在循环结束之前，while loop不检测变量中的更改。

此外，我在窗口的标题栏中更改计数器以显示已完成的点击次数，并且在循环结束前不会更新。

当我按下某个键时，确实收到了NSLog消息。

我很困惑。

我的代码是在这里：

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification { 
    // Insert code here to initialize your application 

[[self myWindow] setLevel:NSFloatingWindowLevel]; 

[NSEvent addGlobalMonitorForEventsMatchingMask:NSKeyDownMask handler:^(NSEvent *event) { 
    keychar = (unichar) event.characters; 
    [NSApp activateIgnoringOtherApps:YES]; 
    stopnow = 1; 
    NSLog(@"Key Pressed = x%x (%x) (%x)",keychar,(keychar&0x7f00),((keychar&0xff00)>>8)); 
}]; 
} 
- (IBAction)setClickPoint:(NSButton *)sender { 
    sleep(5); 
    CGEventRef ourEvent = CGEventCreate(NULL); 
    cgPoint = CGEventGetLocation(ourEvent); 

    myPoint = [NSString stringWithFormat:@" (%5.0f,%5.0f)", cgPoint.x, cgPoint.y]; 
    myNewTitle = [mytitle stringByAppendingString:myPoint]; 
    [[self myWindow] setTitle:myNewTitle]; 
    } 

(IBAction)strtButton:(NSButton *)sender { 
    NSLog(@"Entered strButtn"); 
    numClicks = [_nClicks intValue]; 
    numWait = [_nWait floatValue]; 
    i = 0; 
    while (i < numClicks || numClicks == 0) { 
     i++; 
     myTotal = [NSString stringWithFormat:@" %i of %i", i, numClicks]; 
     myNewTitle = [mytitle stringByAppendingString:myPoint]; 
     myNewTitle = [myNewTitle stringByAppendingString:myTotal]; 

     [[self myWindow] setTitle:myNewTitle]; 

     CGWarpMouseCursorPosition(cgPoint); 

     CGEventRef down = CGEventCreateMouseEvent(0, kCGEventLeftMouseDown,cgPoint, 0); 
     CGEventPost(kCGSessionEventTap, down); 
     CFRelease(down); 

     CGEventRef up = CGEventCreateMouseEvent(0, kCGEventLeftMouseUp,cgPoint, 0); 
     CGEventPost(kCGSessionEventTap, up); 
     CGRealease(up); 

     NSLog(@"stopnow = %i", stopnow); 

     if (stopnow == 1) { 
      stopnow = 0; 
      break; 
     } 

     usleep((unsigned int)(numWait * 1000000.0)); 
    } 
}

来源

2014-04-30 user3581648