UISwipeGestureRecognizer 左右事件捕捉

转自：http://blog.163.com/china_uv/blog/static/117137267201252102612185/

UISwipeGestureRecognizer 左右事件相同为非注释代码， 左右事件不同为注释代码。

@implementation GestureRecognizerViewController

-(id)init
{
    if (self == [super init]) {
        
        UISwipeGestureRecognizer *recognizer;    
        recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];    
        [recognizer setDirection:UISwipeGestureRecognizerDirectionLeft|UISwipeGestureRecognizerDirectionRight];
        [[self view] addGestureRecognizer:recognizer];    
        [recognizer release];
        
//        recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];    
//        [recognizer setDirection:UISwipeGestureRecognizerDirectionLeft];
//        [[self view] addGestureRecognizer:recognizer];    
//        [recognizer release];
//        
//        recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];    
//        [recognizer setDirection:UISwipeGestureRecognizerDirectionRight];
//        [[self view] addGestureRecognizer:recognizer];    
//        [recognizer release];
        
    }
    
    return self;
}

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    self.view.backgroundColor = [UIColor darkGrayColor];
}

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

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

-(void) dealloc
{
    for (UISwipeGestureRecognizer *recognizer in [[self view] gestureRecognizers]) {  
        [[self view] removeGestureRecognizer:recognizer];  
    } 
    
    [super dealloc];
}

// ------------------------------------------------------------------------

- (void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer{    
    
    NSLog(@"direction ------------- %d", recognizer.direction);
    
    
    if (recognizer.direction == (UISwipeGestureRecognizerDirectionLeft | UISwipeGestureRecognizerDirectionRight)) {    
        NSLog(@"left & right");  
    }
    
//    if (UISwipeGestureRecognizerDirectionLeft == recognizer.direction) {    
//        NSLog(@"left");  
//    }
//    
//    if (UISwipeGestureRecognizerDirectionRight == recognizer.direction) {    
//        NSLog(@"right");  
//    }
}

感叹下IOS的智慧，UISwipeGestureRecognizerDirection定义用的是位移。
typedef enum {
    UISwipeGestureRecognizerDirectionRight = 1 << 0,
    UISwipeGestureRecognizerDirectionLeft  = 1 << 1,
    UISwipeGestureRecognizerDirectionUp    = 1 << 2,
    UISwipeGestureRecognizerDirectionDown  = 1 << 3
} UISwipeGestureRecognizerDirection;