Successful Swipe in UITextView?

Question

Has anyone been able to implement a successful swipe gesture on a UITableView? By default this is not possible due to the scrolling nature of the control. I\'ve tried subcla

Answer 1

An even better solution, I have found, is to simply pass touches back to the superview:

@interface SwipeableTextView : UITextView {
}

@end

@implementation SwipeableTextView

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesBegan:touches withEvent:event];

    [self.superview touchesBegan:touches withEvent:event];

}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesMoved:touches withEvent:event];

    [self.superview touchesMoved:touches withEvent:event];
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesEnded:touches withEvent:event];

    [self.superview touchesEnded:touches withEvent:event];
} 

@end

Answer 2

Here is a subclass of a UITextView that will detect a swipes gesture...

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#import <UIKit/UIKit.h>

#define kMinimumGestureLength   25
#define kMaximumVariance        5

@interface SwipeableTextView : UITextView {
    CGPoint gestureStartPoint;
}

@end

@implementation SwipeableTextView

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesBegan:touches withEvent:event];

    UITouch *touch =[touches anyObject];
    gestureStartPoint = [touch locationInView:self];

}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesMoved:touches withEvent:event];

    UITouch *touch = [touches anyObject];
    CGPoint currentPosition = [touch locationInView:self];

    CGFloat deltaX = fabsf(gestureStartPoint.x - currentPosition.x);
    CGFloat deltaY = fabsf(gestureStartPoint.y - currentPosition.y);

    if (deltaX >= kMinimumGestureLength && deltaY <= kMaximumVariance) {
        NSLog(@"Horizontal swipe detected");
    }

}

@end

Answer 3

Add a transparent UIView on top of the UITextView and use it to handle the swipe, and send the touchesBegan/Moved/Ended/Canceled: messages to the text view to preserve normal interaction.

Answer 4

You could also use a two finger swipe. When I get home I can elaborate with some code but that was what I have used

Answer 5

Usually you implement the touch responding events in a UITableViewCell, which can recognize the swipe and do something. UITableViews inherit from UIScrollView which does not like having touch events overridden.

Answer 6

I took Ross's code and added a few things that helped me. In particular, this code won't respond to the swipe until it stops. It also prevents a swipe from reversing direction partway through.

#import <UIKit/UIKit.h>

#define kMinimumGestureLength   25
#define kMaximumVariance        5

typedef enum swipeDirection {
    kSwipeNone,
    kSwipeLeft,
    kSwipeRight
} tSwipeDirection;

@interface SwipeableTextView : UITextView {
    CGPoint gestureStartPoint;
    tSwipeDirection swipeDirection;
}

@end

@implementation SwipeableTextView

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesBegan:touches withEvent:event];

    swipeDirection = kSwipeNone;
    UITouch *touch =[touches anyObject];
    gestureStartPoint = [touch locationInView:self];

}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesMoved:touches withEvent:event];

    UITouch *touch = [touches anyObject];
    CGPoint currentPosition = [touch locationInView:self];

    CGFloat deltaX = fabsf(gestureStartPoint.x - currentPosition.x);
    CGFloat deltaY = fabsf(gestureStartPoint.y - currentPosition.y);

    // Check if we already started a swipe in a particular direction
    // Don't let the user reverse once they get going
    if (deltaX >= kMinimumGestureLength && deltaY <= kMaximumVariance &&
        swipeDirection == kSwipeNone) {
        if (gestureStartPoint.x < currentPosition.x) {
            swipeDirection = kSwipeRight;
        }
        else {
            swipeDirection = kSwipeLeft;
        }
    }
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    if (swipeDirection == kSwipeRight) {
        NSLog(@"Swipe right");
    }
    else if (swipeDirection == kSwipeLeft) {
        NSLog(@"Swipe left");
    }
    [super touchesEnded:touches withEvent:event];
} 

@end