Cascades Development

[slashkyle]

in my previous post I came to the realization that I need to interact with screen events from C++ 

moving this to a new thread because it's not related to the keyboard....

I'm trying to interact with the entire screen (bezel & all) however this doesnt seem to be possible from QML

Im currently using the BPS Monitor & discovered this Multi-touch Handler

I belive that i've managed to get it working with the bps monitor but to test it

my issue is, trying to get a qml label to update with the current X, Y positions

//in appname.cpp

AbstractPane *root = qml->createRootObject<AbstractPane>();
    Label *mLabel = root->findChild<Label*>("rootLabel");
    mLabel->setText("C++ Label");

 I'm able to change the text of the qml label but I do not know how to access the child object in my ScreenService.cpp file, currently its accessed in appName.cpp

case SCREEN_EVENT_MTOUCH_TOUCH:

		if (!found) {

			Touchpoint *tp = new Touchpoint(mtouch_event.x, mtouch_event.y,
					mtouch_event.contact_id);
			if(mtouch_event.contact_id<4){
				//interact with touch events here
				// such as mLabel->setText("X " + mtouch_event.x + ", Y " + mtouch_event.y);
			}

[Zmey]

Hi,

You can do something like this in any object:

Label *s = Application::instance()->scene()->findChild<Label *>(
"rootLabel");

From the encapsulation point of view it's better to emit the signal with coordinates from child object and subscribe to this signal in interface class and update the label there.

[slashkyle]

doing that in screenService.cpp tells me that application is not declared....

It would probably be easier if i linked the X & Y values from screenService & update the label with them later but I still have no idea how to do such a thing using c++, once i want to leave the current page with a value, nothing wants to work

i do have access to touchpoint.cpp/h , it has a value of Touchpoint::getX & getY which would return the values to me if it ever decides to cooperate

[Zmey]

Add these lines to screenService.cpp:

#include <bb/cascades/Application>
using namespace bb::cascades;

Regarding the second approach:

Declare a signal in ScreenService header:

signals:
  void positionUpdated(int x, int y);

Emit the signal when position updates:

emit positionUpdated(newX, newY);

Now any other class can subscribe to this signal. 

Declare a slot in class which instantiates ScreenService:

public slots:
  void onPositionUpdated(int x, int y);

After creating ScreenServer instance connect it's signal to the slot:

QObject::connect(screenServer, SIGNAL(positionUpdated(int,int)),
  this, SLOT(onPositionUpdated(int,int)));

In onPositionUpdated handler update the label.

[slashkyle]

thanks for the fast response, that light everything up as if it should work but when i go to build it tells me 

invalid use of incomplete type 'struct bb::cascades::AbstractPane'

[Zmey]

Include all incomplete types in .cpp file as well:
#include <bb/cascades/AbstractPane>
etc

Updated my previous answer with more details on signal/slot approach.

[slashkyle]

Thanks again for the help, i've nearly figured it out & sorry to be a plague c++ is not my friend

it's saying newX & Y don't exist so

emit positionUpdated(newX, newY);

 if i replace it with this which is setup to values set touchpoint.cpp

emit positionUpdated(mtouch_event.x, mtouch_event.y);

it gives me no errors (or visible results) when i build this

void ScreenService::onPositionUpdated(int x, int y){
	QString xstring = QString::number(x);
	QString ystring = QString::number(y);
	Label *s = Application::instance()->scene()->findChild<Label *>(
	"rootLabel");
	QObject::connect(s, SIGNAL(positionUpdated(int,int)),
	  this, SLOT(onPositionUpdated(int,int)));
	s->setText("X " + xstring + ", Y " + ystring);

}

 ...if only this all worked in qml i'd have been done days ago lol

--Edit after removing all intergers etc, i was unable to get the label text to change while on the services.cpp page so i went back to appName.cpp & the text changes like a charm

    AbstractPane *root = qml->createRootObject<AbstractPane>();
    Label *mLabel = root->findChild<Label*>("rootLabel");
    mLabel->setText("C++ Label");

 only, I've no clue how to pull the integer values from touchpoint.cpp's Touchpoint::getX & getY & update the text with that information from appName.cpp

[Zmey]

No problem.

The simplest approach is probably going back to the original code and replacing this line:

// such as mLabel->setText("X " + mtouch_event.x + ", Y " + mtouch_event.y);

with:

Label *rootLabel = Application::instance()->scene()->findChild<Label *>("rootLabel");
QString xString = QString::number(mtouch_event.x);
QString yString = QString::number(mtouch_event.y);
rootLabel->setText("X " + xString + ", Y " + yString);

And adding

#include <bb/cascades/Application>

#include <bb/cascades/Label>

using namespace bb::cascades;

on the top of the file.