Cascades Development

[nareshkodumuri]

Hi,

      I am doing a simple application in which I have created qmlDocument object by loading main.qml file in app.cpp file.Now i want to use the object created in app.cpp file in another class .I tried this by including this App class in another class declaration.But if i am using the object created in app,cpp file in another class it is showing error.And i tried like this creating the qmldocument object by loading the same qml file in another class.But it is also not working.Please provide the solution.

Regards,

NareshKodumuri.

[smacmartin]

This is a C++ question; ignore cascades for the moment.

Usually you'll want a method in the main app, or even a standalone function in a namespace, that fetches the data once then returns it.  Then this is called from your main code and from the other code.

You can be fancier, but basically, one place creates the variable and manages its lifetime, and other places can ask for it.  You can use Qt smart pointer classes to manage the memory and keep references around, or sometimes you know the object will live for longer than the other callers will want it.

Now for your specific situation:

If you think you are already doing this, the next step is to look at the exact error you are getting, and maybe use the debugger.  Can you provide more details?  Is it a compile error or runtime error?   If you are using pointers, did you make sure that the pointer is 0 rather than some arbitrary value before you load it?

Stuart

[nareshkodumuri]

Hi,

    Thanks for ur reply.Here is the code where i am getting problem.

   app.cpp

----------------

#include "app.hpp"
#include "DateBox.hpp"

#include <bb/cascades/Button>
#include <bb/cascades/Application>
#include <bb/cascades/QmlDocument>
#include <bb/cascades/AbstractPane>
#include <bb/cascades/Container>
#include <bb/cascades/Color>
#include <bb/cascades/Page>
#include <bb/cascades/Label>
#include <bb/cascades/AbsoluteLayoutProperties>
#include <bb/cascades/DockLayoutProperties>
#include <bb/cascades/DockLayout>
#include <bb/cascades/ImagePaint>
#include <QDateTime>

using namespace bb::cascades;

//global variables

QString monArray[12] = { "Jan", "Feb", "Mar", "Apr", "May", "June", "July",
		"Aug", "Sep", "Oct", "Nov", "Dec" };
QDate date;
int x;
int y;
int cols;
int year;
int month;
int day;
QVariant currentDay;
bool row_inserted;
Container *btnContainer;
Button *nextMon, *prevMon;
Label *lbl;
int i, firstDay, daycount = 0, totalNoOfDaysInMonth = 0,j;
static int monIndex;
static int yearIndex;
static int dow;
QString timeString;

Label *curDateLabel;

App::App() {
	date = QDate::currentDate();
	QString curdate = QDate::currentDate().toString("dd-MM-yyyy");

	year = date.year();
	yearIndex=date.year();

	month = date.month();
	monIndex=date.month();

	day = date.day();

	qmlRegisterType<DateBox>("my.datebox", 1, 0, "DateBox");

	//created a qml document object.I need to use this object in DateBox class
	qml = QmlDocument::create("main.qml");
	//setting context property
	qml->setContextProperty("add_dates", this);

	page = qml->createRootNode<Page>();
//finding the container for changing background
	cont_cal = page->findChild<Container *>("cont_calendar");
	curDateLabel=page->findChild<Label *>("curdate");
	firstDay = firstDayOfMonth(month, year);
	totalNoOfDaysInMonth = totalNoOfDays(month, year);
	Application::setScene(page);
}

void App::addContainers() {

	if(cont_cal->count()>0)
		cont_cal->removeAll();
	x = 3;
	y = 3;
	cols = 0;
	currentDay = 0;
	row_inserted = false;
	j = 1;
	for (int i = 0; i < 49; i++) {
		if (cols == 7) {
			row_inserted = true;
			cols = 0;
			y += 98;
		}
		if (row_inserted) {
			x = 3;
			row_inserted = false;
		}
		QString curDate = "";
		if (i >= firstDay) {
			if (j <= totalNoOfDaysInMonth) {
				currentDay = j;
				curDate = currentDay.toString();
				j++;
			}
		}
		DateBox *dateBox = new DateBox();
		dateBox->setLayoutProperties(AbsoluteLayoutProperties::create().position(x, y));
		qDebug()<<curDate;
		dateBox->setLabelText(curDate);
		cont_cal->add(dateBox);
		x += 109;
		cols++;
	}
	QVariant yearVal=yearIndex;
	QString yearValue=yearVal.toString();
	qDebug()<<yearVal;
	qDebug()<<yearValue;
	curDateLabel->setText(monArray[monIndex-1]+"-"+yearValue);
}
int App::firstDayOfMonth(int months, int year) {
	int mon = months;
	int yearNumber = year;
	dow = 6;
	for (int i = 1583; i < yearNumber; i++)
		dow += (checkLeap(i)) ? 2 : 1;

	for (int i = 1; i < mon; i++) {
		dow += totalNoOfDays(i, year);
	}
	dow = dow % 7;
	return dow;
}

int App::totalNoOfDays(int months, int year) {
	switch (months) {
	case 1:
		return 31;
		break;
	case 2:
		if (checkLeap(year))
			return 29;
		else
			return 28;
		break;
	case 3:
		return 31;
		break;
	case 4:
		return 30;
		break;
	case 5:
		return 31;
		break;
	case 6:
		return 30;
		break;
	case 7:
		return 31;
		break;
	case 8:
		return 31;
		break;
	case 9:
		return 30;
		break;
	case 10:
		return 31;
		break;
	case 11:
		return 30;
		break;
	case 12:
		return 31;
		break;
	default:

		break;
	}
	return 0;

}

bool App::checkLeap(int year) {
	if ((year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0)))
		return true;
	else
		return false;

}

void App:: btnNextFunction() {
	qDebug()<<"btnNextFunction called";
	qDebug()<<monArray[monIndex-1];
	qDebug()<<monIndex;
	monIndex = monIndex + 1;
	qDebug()<<monIndex;
	//qDebug()<<monIndex;
	if (monIndex <= 12)
	{

		firstDay = firstDayOfMonth(monIndex, yearIndex);
		qDebug()<<firstDay;
		qDebug()<<yearIndex;
		totalNoOfDaysInMonth = totalNoOfDays(monIndex, yearIndex);
	}
	if (monIndex > 12) {
		yearIndex = yearIndex + 1;
		monIndex = 1;
		firstDay=firstDayOfMonth(monIndex, yearIndex);
		qDebug()<<firstDay;
		totalNoOfDaysInMonth = totalNoOfDays(monIndex, yearIndex);
	}
	addContainers();
}

void App:: btnPrevFunction() {
   addContainers();
	monIndex = monIndex - 1;
	if (monIndex > 0)
	{
		firstDay = firstDayOfMonth(monIndex, yearIndex);
		totalNoOfDaysInMonth = totalNoOfDays(monIndex, yearIndex);
	}

	if (monIndex == 0) {
		yearIndex = yearIndex - 1;
		monIndex = 12;
		firstDay = firstDayOfMonth(monIndex, yearIndex);
		totalNoOfDaysInMonth = totalNoOfDays(monIndex, yearIndex);
	}
	addContainers();
}

app.hpp

-------------

#ifndef APP_H
#define APP_H

#include <QObject>
#include <bb/cascades/Container>
#include <bb/cascades/TouchEvent>
#include <bb/cascades/Label>
#include <bb/cascades/QmlDocument>
#include <bb/cascades/Page>
using namespace bb::cascades;
/*!
 * @brief Application GUI object
 */
class App: public QObject {
Q_OBJECT

public:
	App();
	Q_INVOKABLE void addContainers();
	Container *cont_cal;
	Label *lbl;
	Container *cont;
	QmlDocument *qml;
	Page *page;
	int firstDayOfMonth(int, int);
	int totalNoOfDays(int, int);
	bool checkLeap(int);
	Q_INVOKABLE void btnPrevFunction();
	Q_INVOKABLE void btnNextFunction();




};


#endif // ifndef APP_H

 DateBox.cpp

--------------------

#include "DateBox.hpp"
#include "App.hpp"
#include <bb/cascades/Container>
#include <bb/cascades/CustomControl>
#include <bb/cascades/DockLayout>
#include <bb/cascades/AbsoluteLayoutProperties>
#include <bb/cascades/DockLayoutProperties>
#include <bb/cascades/TextStyle>
#include <bb/cascades/QmlDocument>
#include <bb/cascades/AbstractPane>
#include <bb/cascades/ImagePaint>
#include <bb/cascades/ImageTracker>

using namespace bb::cascades;
//ImageTracker *imgPaint;
DateBox::DateBox()
{
/* I want to use the objects created in app.cpp file (qmlDocument,root node and container where i need to change the background) in this file*/

//	mainQml = QmlDocument::create("main.qml");
//	mainPage = mainQml->createRootNode<AbstractPane>();
//	cont_cal = mainPage->findChild<Container *>("cont_calendar");

	cont = Container::create()
				.preferredSize(106, 95)
				.leftMargin(3)
				.topMargin(3)
				.layout(DockLayout::create())
				.background(Color::Transparent);
	lbl = Label::create()
				.layoutProperties(DockLayoutProperties::create()
													.horizontal(HorizontalAlignment::Center)
													.vertical(VerticalAlignment::Center));
	cont->add(lbl);
	bool res=QObject::connect(cont,SIGNAL(touch(bb::cascades::TouchEvent *)),this,SLOT(onTouch()));
	Q_ASSERT(res);
	Q_UNUSED(res);
	setRoot(cont);
}

void DateBox::setLabelText(QString text)
{
	lbl->setText(text);
}

QString DateBox::getText()
{
	return lbl->text();
}


void DateBox::onTouch()
{


	qDebug()<<"method called";

	//the text on the label
	qDebug()<<getText();
	//this is the container where i need to set the background for a container.But this is not
	//applying
	cont_cal->setBackground(ImagePaint(QUrl("asset:///images/flower2.png"),RepeatPattern::XY));
}

 DateBox.hpp

--------------------

#ifndef DATEBOX_H
#define DATEBOX_H

#include <QObject>
#include <QString>
#include <bb/cascades/CustomControl>
#include <bb/cascades/Container>
#include <bb/cascades/Label>
#include <bb/cascades/QmlDocument>
#include <bb/cascades/AbstractPane>
using namespace bb::cascades;

class DateBox:public bb::cascades::CustomControl,public App
{
	Q_OBJECT
	Q_PROPERTY(QString text READ getText WRITE setLabelText);

public:
	Container *cont/*, *cont_cal*/;
	Label *lbl;
	/*QmlDocument *mainQml;
	AbstractPane *mainPage;*/
	DateBox();
	void setLabelText(QString);
	QString getText();
public slots:
	void onTouch();
};

#endif

 main.qml

---------------

import bb.cascades 1.0
import my.datebox 1.0

//-- create one page with a label and text

Page {
    objectName: "page_calendar"
    content: Container {
        objectName: "cont_main"
        layout: StackLayout {
        }
        Container {
            layout: DockLayout {
            }
            preferredWidth: 768
            Button {
                text: "prev"
                preferredWidth: 120
                layoutProperties: DockLayoutProperties {
                    horizontalAlignment: HorizontalAlignment.Left
                    verticalAlignment: VerticalAlignment.Top
                }
                onClicked: {
                    add_dates.btnPrevFunction();
                }
            }
            Label {
                objectName: "curdate"
                id: lbl_calendar
                text: ""
                layoutProperties: DockLayoutProperties {
                    verticalAlignment: VerticalAlignment.Center
                    horizontalAlignment: HorizontalAlignment.Center
                }
                textStyle {
                    base: SystemDefaults.TextStyles.TitleText
                    color: Color.create("#FA5906")
                }
            }
            Button {
                text: "next"
                preferredWidth: 120
                layoutProperties: DockLayoutProperties {
                    horizontalAlignment: HorizontalAlignment.Right
                    verticalAlignment: VerticalAlignment.Top
                }
                onClicked: {
                    console.debug("clicked");
                    add_dates.btnNextFunction();
                }
            }
        }
        Container {
            preferredHeight: 98
            preferredWidth: 768
            background: Color.Red
            layout: StackLayout {
                layoutDirection: LayoutDirection.LeftToRight
            }
            layoutProperties: AbsoluteLayoutProperties {
            }
            id: cont_weekdays
            Label {
                text: "  SUN"
                layoutProperties: StackLayoutProperties {
                    spaceQuota: 1
                    verticalAlignment: VerticalAlignment.Center
                    horizontalAlignment: HorizontalAlignment.Center
                }
            }
            Label {
                text: "MON"
                layoutProperties: StackLayoutProperties {
                    spaceQuota: 1
                    verticalAlignment: VerticalAlignment.Center
                    horizontalAlignment: HorizontalAlignment.Center
                }
            }
            Label {
                text: "TUE"
                layoutProperties: StackLayoutProperties {
                    spaceQuota: 1
                    horizontalAlignment: HorizontalAlignment.Center
                    verticalAlignment: VerticalAlignment.Center
                }
            }
            Label {
                text: "WED"
                layoutProperties: StackLayoutProperties {
                    spaceQuota: 1
                    horizontalAlignment: HorizontalAlignment.Center
                    verticalAlignment: VerticalAlignment.Center
                }
            }
            Label {
                text: "THU"
                layoutProperties: StackLayoutProperties {
                    spaceQuota: 1
                    horizontalAlignment: HorizontalAlignment.Center
                    verticalAlignment: VerticalAlignment.Center
                }
            }
            Label {
                text: "FRI"
                layoutProperties: StackLayoutProperties {
                    spaceQuota: 1
                    horizontalAlignment: HorizontalAlignment.Center
                    verticalAlignment: VerticalAlignment.Center
                }
            }
            Label {
                text: "SAT"
                layoutProperties: StackLayoutProperties {
                    spaceQuota: 1
                    horizontalAlignment: HorizontalAlignment.Center
                    verticalAlignment: VerticalAlignment.Center
                }
            }
        }
        Container {
            id: cont_cal
            objectName: "cont_calendar"
            preferredWidth: 768
            preferredHeight: 700
            layout: AbsoluteLayout {
            }
            layoutProperties: StackLayoutProperties {
                horizontalAlignment: HorizontalAlignment.Center
            }
            background: back.imagePaint
            attachedObjects: [
                ImagePaintDefinition {
                    id: back
                    repeatPattern: RepeatPattern.XY
                    imageSource: "asset:///images/flower.jpg"
                }
            ]
        }
        Button {
            text: "Add"
            onClicked: {
                console.debug("calling add method");
                add_dates.addContainers();
            }
        }
    }
}

 Please provide me the solution.

Naresh Kodumuri

[lingBB10Dev]

It seems to me that this is a pure C++ design choice.

If you want to access the "qml" attribute of the "App" object in the constructor of "DateBox", then you can choose to 

either

  implement "App" as a singleton, then, access its attribute in the constructor of tthe "DateBox"

Or

 pass the pointer of the "qml" attribute of he "App" object as a parameter of the constructor of "DateBox".