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How can I detect Button press / release [message #29486]

Sat, 23 October 2010 18:22

jerson
Messages: 202
Registered: June 2010
Location: Bombay, India

Experienced Member

Greetings everyone

Can someone point me to a callback for button which does the following

WhenPush - I know this one
WhenRelease - does this exist?

I am trying to implement a feature which needs a particular pin on an I/O device to be high as long as the button is pushed/repeat action. The pin has to go low when the button is released.

How can I achieve this?

Thank you for your attention

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Re: How can I detect Button press / release [message #29487 is a reply to message #29486]

Sat, 23 October 2010 20:20

dolik.rce
Messages: 1791
Registered: August 2008
Location: Czech Republic

Ultimate Contributor

jerson wrote on Sat, 23 October 2010 18:22

Can someone point me to a callback for button which does the following

WhenPush - I know this one
WhenRelease - does this exist?

Hi Jerson,

WhenAction is called when the mouse button is released above the button widget. If you also need to detect when user moves the mouse pointer out of the widgets area (which you probably want, otherwise your I/O pin would stay in high state), then you can either inherit from Button and overwrite MouseLeave() to take care of that. Other solution (without making your own class) might be some ugly use of WhenRepeat with timecallbacks setting turning the state of pin after some time unless another WhenRepeat is called, but that would be ugly and error prone.

Best regards,
Honza

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Re: How can I detect Button press / release [message #29490 is a reply to message #29487]

Sat, 23 October 2010 22:31

koldo
Messages: 3432
Registered: August 2008

Senior Veteran

Hello Jerson

I would do a new class from Button deriving virtual LeftDown() and LeftUp() methods.

Best regards
Iñaki

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Re: How can I detect Button press / release [message #29494 is a reply to message #29486]

Sun, 24 October 2010 04:18

jerson
Messages: 202
Registered: June 2010
Location: Bombay, India

Experienced Member

Hi Koldo

I'm a bit fuzzy on this one. Can you help me a bit more as to how to do this? This is how I did it now

class JfButton : public Button {
public:
	virtual void   LeftDown(Point, dword);
	virtual void   LeftUp(Point, dword);
};

and in my App, this

void	JfButton::LeftDown(Point p, dword dw)
{
	SetLabel("Pushed");
}

void	JfButton::LeftUp(Point p, dword dw)
{
	SetLabel("Released");
}

I understand Honza's point about releasing the button outside the widget rectangle and can see it hang. Surely I need to look at how to release when the Mouse leaves the widget rectangle.

Edit:
I no longer see the button being redrawn to pushed state. Is there something more that needs to be done to get this?

Regards

[Updated on: Sun, 24 October 2010 04:25]

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Re: How can I detect Button press / release [message #29495 is a reply to message #29494]

Sun, 24 October 2010 10:24

dolik.rce
Messages: 1791
Registered: August 2008
Location: Czech Republic

Ultimate Contributor

Hi Jerson,
This should take care of everything:

class JfButton : public Button {
public:
	virtual void   LeftDown(Point, dword);
	virtual void   LeftUp(Point, dword);
	virtual void   MouseLeave();
	virtual void   MouseEnter(Point, dword);
};
void	JfButton::LeftDown(Point p, dword dw){
	SetLabel("Pushed");
}
void	JfButton::LeftUp(Point p, dword dw){
	SetLabel("Released");
}
void	JfButton::MouseLeave(){
	SetLabel("Released");
	Button::MouseLeave();
}
void	JfButton::MouseEnter(Point p,dword dw){
	if(dw&K_MOUSELEFT){SetLabel("Pushed");}
	Button::MouseEnter(p,dw);
}

Honza

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Re: How can I detect Button press / release [message #29496 is a reply to message #29486]

Sun, 24 October 2010 14:34

jerson
Messages: 202
Registered: June 2010
Location: Bombay, India

Experienced Member

Hi Honza

thanks for your example code. I really appreciate your help.

I was getting some strange behaviour on Push and Release like having to move the mouse to see the button push painting or moving the mouse after releasing the button to see button release painting.

This is what made it work

void    JfButton::LeftDown(Point p, dword dw){
    SetLabel("Pushed");
    KeyPush();   // draw the button push state
}
void    JfButton::LeftUp(Point p, dword dw){
    SetLabel("Released");
    FinishPush(); // draw button release state
}

Regards

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