iphone - UIGestureRecognizer サブクラスでスワイプを実装する方法

Question

UIGestureRecognizerサブクラスでスワイプをどのように実装しますか?

(なぜ を使用する代わりにこれを実行したいのか疑問に思っている場合は、 Chameleonの UIKit ポートUISwipeGestureRecognizerにスワイプ認識を追加したいからです)

Answer 1

私の最初の試み（Githubでも）：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];
    _beganLocation = [touch locationInView:self.view];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];
    CGPoint movedLocation = [touch locationInView:self.view];
    CGFloat distance = _distance(_beganLocation, movedLocation);

    if (distance < SWIPE_MIN_DISTANCE) return;

    CGFloat angle = _angle(_beganLocation, movedLocation);
    int direction = -1;
    if (angle > 270 - SWIPE_MAX_ANGLE && angle < 270 + SWIPE_MAX_ANGLE) {
        direction = UISwipeGestureRecognizerDirectionUp;
    }
    if (angle > 180 - SWIPE_MAX_ANGLE && angle < 180 + SWIPE_MAX_ANGLE) {
        direction = UISwipeGestureRecognizerDirectionLeft;
    }
    if (angle > 90 - SWIPE_MAX_ANGLE && angle < 90 + SWIPE_MAX_ANGLE) {
        direction = UISwipeGestureRecognizerDirectionDown;
    }
    if ((angle > 360 - SWIPE_MAX_ANGLE && angle <= 360) || (angle >= 0 && angle <= SWIPE_MAX_ANGLE)) {
        direction = UISwipeGestureRecognizerDirectionRight;
    }

    if (direction == -1) {
      self.state = UIGestureRecognizerStateFailed;
    } else {
      self.state = self.direction == direction ? UIGestureRecognizerStateRecognized : UIGestureRecognizerStateFailed;
    }
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    self.state = UIGestureRecognizerStateFailed;
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
    self.state = UIGestureRecognizerStateFailed;
}

補助機能:

static CGFloat _distance(CGPoint point1,CGPoint point2)
{
    CGFloat dx = point2.x - point1.x;
    CGFloat dy = point2.y - point1.y;
    return sqrt(dx*dx + dy*dy);
};

static CGFloat _angle(CGPoint start, CGPoint end)
{
    CGPoint origin = CGPointMake(end.x - start.x, end.y - start.y); // get origin point to origin by subtracting end from start
    CGFloat radians = atan2f(origin.y, origin.x); // get bearing in radians
    CGFloat degrees = radians * (180.0 / M_PI); // convert to degrees
    degrees = (degrees > 0.0 ? degrees : (360.0 + degrees)); // correct discontinuity
    return degrees;
}

Chameleonのジェスチャ認識機能の実装は不完全であり、おそらく Twitterrific に固有のロジックが含まれていることに注意してください。私たちのフォークには、さらに修正が含まれています。