[feature request] support custom handler for gestures

[liuxuan30]

I looked at current swift code, seems like the gestures and private and I cannot provide custom handler to replace the default one?

Say if PieRadarChartViewBase has a doubleTapGestureRecognizer (which does not exist right now), the default behaviour is the zooming feature. Now I don't want zoom I want to double tap to be my own handler.

I think the complicated part is supporting both Objective-C and swift block. I am not sure is there any evil there. like retain cycle or others.

[danielgindi]

Of course you can. It behaves like any other UIView. You can explicitpy disable the gestures with the dedicated properties, or work with the gestureRecognizers array.

[liuxuan30]

could you give the key word? How to provide the block? I don't see a place I can provide my own block via a API.

[liuxuan30]

well I think I know what to ask: is there any public API to get the data set / xIndex etc. if I give a location (CGPoint)

What I want is I can provide a touch location, and want to get the dataSet and xIndex, etc. to know what value is double tapped.

[danielgindi]

Well I'm not in front of the code right now, but why won't you check out the code of the tap handler? You'll see that there are helper functions for everything...

[liuxuan30]

I did, but it seems I have to write a function to get the data set or whatever given a location. I don't see a similar function do this in Utils. Just want to check if there is. I think this API is useful.

[liuxuan30]

What I am looking for is like below:

    public func xIndexAtPoint(point: CGPoint) -> Int {
        var distance = distanceToCenter(x: point.x, y: point.y);
        // check if a slice was touched
        if (distance <= self.radius)
        {
            var angle = angleForPoint(x: point.x, y: point.y);

            if (self.isKindOfClass(PieChartView))
            {
                angle /= _animator.phaseY;
            }

            var index = indexForAngle(angle);

            // check if the index could be found
            if (index < 0)
            {
                return NSNotFound;
            }
            else
            {
                return index;
            }
        } else {
            return NSNotFound;
        }
    }

Do you think such kind of functions is useful for other people?

[danielgindi]

So why not just use xIndexAtPoint?

[liuxuan30]

yeah I am using it. But I am wondering if such functions can be useful for others.

[danielgindi]

Of course, they are not public for nothing...

[zxhfirefox]

@danielgindi , I think all the gesture handler function should be internal, or even public.
Because, although we can get the gesture from the view, and change it with our own handler, or delegate and other properties, but there are some private properties, that our own handler will be very hard to make it consistent, and we want to reuse the default handler. So we can do in our own handler like this

override func tapGestureRecognized(recognizer:UITapGestureRecognizer)
{
       super.tapGestureRecognized(recognizer)
       // our own code here.
}

[liuxuan30]

This is the PR #268

Better to let the gestures itself as internal discussed in PR, and you can have your own private gesture handlers.

[zxhfirefox]

@liuxuan30 Great!

[ashish1703]

@zxhfirefox i want to override doubletap on all say a batchart. Is there a way i can do it?
What i am doing currently with no result whatsoever is:

UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(touch:)];
[tap setNumberOfTapsRequired:1]; // Set your own number here
[tap setDelegate:self]; // Add the protocol

add the gesture to the chartview.

Any help in this respect will be world of good for me.

[ghost]

You cannot have multiple tap gesture recognizers of the same type on the same view in iOS. They will conflict. Research it. It would be great if the library allowed us to add our own custom tap handler or gave us a tapped hook method.