Making a KeyBoard into LCD connected with the ARM board.how can i ?

[savaliya_ambani]

hi all,

I am a newbie to the Qt programming.And i have an TouchScreen LCD connected with the ARM controller.
My goal is very simple.I have one QlineEdit(assume a scrren/form) box into this 7" LCD.

I want to make a QWERTY Keyboard into this LCD at the bottom side.Now when ever i presses any key,it should display the
same Key in the the LineEdit box/Form. I mean if i press "1" it should display a 1. Can any one please guide me into this
creation?

Thanks to all who helps to the programmer.

[savaliya_ambani]

hello,

Please reply me some one with some hints and guidelines so that i can proceed into my work. I am planning to use
QKeyEvent ,but i dont know how to generate a key (like we generate pushbutton from QPushButton).

please reply some one.Thanks.

[zuck]

In your case you can use a lot of existent keyboard widgets and/or input methods.

You can find them, for example, on qt-apps.org: search for "virtual keyboard".

[savaliya_ambani]

hi,Thanks for reply.

Isnt it possible to make my own keypad on LCD window?please let me know the various ways of doing this.

I am thinking of with QPushButton,but its very lond. i need to implement slots for each and every button.

i have tried with the QSignalMapper example given in the examples.In that they have used QStringList.I have used six
keys in that.i.e. A list of Six word as "123456". But when i presses any key,it goes to the single slots.so i cant identify which one is pressed?

can any one please tell me how can i find a particular key from map() or mapped()?

Also suggest other ways of builiding keypad or provide the links.please.

THANK YOU ALL.

[QbelcorT]

hi, I managed to make a basic keyboard on my touchscreen, for WIFI key input. I made an object called 'alphapad', this displays the keyboard and emits a QKeyEvent using QCoreApplication::sendEvent. I have the source, but you will need to find your own images. It is a QGraphicsView with QGraphicItem.

[savaliya_ambani]

ohhhhhhhh congratulations.

This is really a nice thing. And will be helpfull to all the developers.

So,is it that each key is a pushbutton or a key? which base object you have taken for a key widget?I am thinking of taking each key as a pushbutton object. i can imagine only half picture from what you ahve said as far as design is concerned. becasue i dont know much about keyevents and QGraphicsItem.

Any way please guide me in my development. Thanks again.

With regards,
savaliya.

[QbelcorT]

Hi,
Most of my buttons for the touchscreen are based from an example of Qt code. In the Qt package there is an example under qgraphicsview, called pad navigator. The buttons are using the object roundrectitem.cpp,h. It is a QGraphicsItem. I don't have a way to post the files here. Message me. Here is a snippet, when the button is pressed this slot is called.

void AlphaPad::numEntry(QGraphicsItem *item)
{
	QVariant count = item->data(QVariant::Int);
 
	int keyValue = count.value<int>();
	// toggle the alpha characters, repaint the text inthe button
	if (keyValue == Qt::Key_CapsLock)
	{
		m_caseToggle ^= 1;
		for ( int y = 0; y < m_height; ++y)
		{
			for (int x = 0; x < m_width; ++x)
			{
				RoundRectItem *item	= qgraphicsitem_cast<RoundRectItem *>(grid[y][x]);
				QString charString;
				if (m_caseToggle == true)
					charString = itemValue[y][x].toLower();
				else
					charString = itemValue[y][x].toUpper();
				if (itemValue[y][x] != QChar::Null)
					item->setText(charString,QFont(ALPHAPADFONT),
											QColor(ALPHATEXTCOL),
											QRectF(QPointF(ALPHATEXTRECTTL),QPointF(ALPHATEXTRECTBR)));
			}
 
		}
	}
 
	QChar keyChar = count.toChar();
	QString unicodeval(count.toChar());
 
	 // for alphabet encoding
	//  alter the keypress value for lower case
	if ((keyValue <= Qt::Key_Z && keyValue >= Qt::Key_A) && 
			m_caseToggle == true)
	{
		keyValue += 0x20;		// for lower case
		keyChar = keyValue;
		unicodeval = keyChar;
	}
 
	if (recObject)
	{
		QLineEdit *lineEdit = qobject_cast<QLineEdit *>(recObject);
		if(keyValue == Qt::Key_Enter)
		{
			unicodeval = "d";
			if(lineEdit->hasAcceptableInput())
			{
				emit finished();
				hidePad();
			}
			else
			{
				lineEdit->undo();
			}
		}
		else if(keyValue == Qt::Key_Backspace)
				unicodeval = "08";
		else if(keyValue == Qt::Key_CapsLock)
			return;
 
		QKeyEvent keyPress(QEvent::KeyPress,keyValue,Qt::NoModifier,unicodeval);
		QCoreApplication::sendEvent(recObject,&keyPress);
	}
	if(keyValue == Qt::Key_Enter)
		hidePad();
 
	qDebug() << "KeyPressed" << unicodeval << keyValue;
}

void AlphaPad::numEntry(QGraphicsItem *item)
{
	QVariant count = item->data(QVariant::Int);

	int keyValue = count.value<int>();
	// toggle the alpha characters, repaint the text inthe button
	if (keyValue == Qt::Key_CapsLock)
	{
		m_caseToggle ^= 1;
		for ( int y = 0; y < m_height; ++y)
		{
			for (int x = 0; x < m_width; ++x)
			{
				RoundRectItem *item	= qgraphicsitem_cast<RoundRectItem *>(grid[y][x]);
				QString charString;
				if (m_caseToggle == true)
					charString = itemValue[y][x].toLower();
				else
					charString = itemValue[y][x].toUpper();
				if (itemValue[y][x] != QChar::Null)
					item->setText(charString,QFont(ALPHAPADFONT),
											QColor(ALPHATEXTCOL),
											QRectF(QPointF(ALPHATEXTRECTTL),QPointF(ALPHATEXTRECTBR)));
			}

		}
	}
	
	QChar keyChar = count.toChar();
	QString unicodeval(count.toChar());

	 // for alphabet encoding
	//  alter the keypress value for lower case
	if ((keyValue <= Qt::Key_Z && keyValue >= Qt::Key_A) && 
			m_caseToggle == true)
	{
		keyValue += 0x20;		// for lower case
		keyChar = keyValue;
		unicodeval = keyChar;
	}

	if (recObject)
	{
		QLineEdit *lineEdit = qobject_cast<QLineEdit *>(recObject);
		if(keyValue == Qt::Key_Enter)
		{
			unicodeval = "d";
			if(lineEdit->hasAcceptableInput())
			{
				emit finished();
				hidePad();
			}
			else
			{
				lineEdit->undo();
			}
		}
		else if(keyValue == Qt::Key_Backspace)
				unicodeval = "08";
		else if(keyValue == Qt::Key_CapsLock)
			return;

		QKeyEvent keyPress(QEvent::KeyPress,keyValue,Qt::NoModifier,unicodeval);
		QCoreApplication::sendEvent(recObject,&keyPress);
	}
	if(keyValue == Qt::Key_Enter)
		hidePad();
	
	qDebug() << "KeyPressed" << unicodeval << keyValue;
}

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[savaliya_ambani]

Ohhh yes, i am seeing that keypad examples in graphicsview.

can u please send me the source to my mail id,please? My e-mail id id savaliya_ambani@yahoo.co.in

Actually ,we want to add our icons on each key button. Thats under development.

i will be very very thankful to yours.

With regards,
savaliya

[savaliya_ambani]

hellow,can u please send me same source file again,as i have lost it from my mail and harddisk.

please,send on the same is:savaliya_ambani@yahoo.co.in.

waiting for it.Thanking you.

[chetu1984]

Hi,
I am really new to Qt and also C++, the discussion about creating a virtual keyboard was very interesting but i was not able to understand exactly where to start with building a virtual keyboard. If anyone could explain me, It would be really a big help.

Thanks,
regards

[savaliya_ambani]

You can read about the QSignalMapper and QPushButton. i Hope you will get the Understanding.

[chetu1984]

Thank you for the Quick Reply. Today I read about the QSignalMapper the whole day. I am trying to make an example on my own and Hopefully I can get back to you with some more questions.

Thanks Much,
Regards,