Custom QWidget Keyboard first time click issue.

Arvind K

For a General Application we have login form with on screen custom keyboard. Keyboard is designed with QWidget. When we try to enter a value with on screen keyboard , at first time it's not taking any input(i.e. button click) afterwards all buttons are working fine. We have tried to set a focus programmatically but its not working. Please give a solution for the same.
We observed that keyboard is working fine if we call on Pushbutton click, but its not working with QLineEdit.

dheerendra

Event not received indicates that event is taken some other object and processed before it reaches keyboard widget. Did try running the program with H/W keyboard ? Which platform did you try this ?

Arvind K

@dheerendra
For our Application we don't want to use H/W keyboard.
We are using Ubuntu 16.04 , 64bit system with Touchscreen display.

mrjj

@Arvind-K
Hi
since you are showing no code, i wont speculate on what error might be.

Anyway, try using QGuiApplication::focusObject();
and see what widget has the focus.

For my widget keyboard, i have all buttons set to NoFocus for focusPolicy as else they
steal focus on first shown, unless i control it very tight.

Arvind K

----------------- Login widget Code -------------------------------

frmlogin.h

#include <QWidget>
#include "keyboard/keyboard.h"
#include "messagebox.h"

namespace Ui {
class FrmLogin;
}

class FrmLogin : public QWidget
{
Q_OBJECT

public:
Ui::FrmLogin *ui;
explicit FrmLogin(QWidget *parent = 0);
~FrmLogin();

private slots:
void run_keyboard_lineEdit();
void on_BtnCancel_clicked();

protected:
void showEvent(QShowEvent *event);

private:
Keyboard *lineEditkeyboard;
};

frmlogin.cpp

FrmLogin::FrmLogin(QWidget *parent) :
QWidget(parent),
ui(new Ui::FrmLogin)
{

ui->setupUi(this);
setGeometry(QStyle::alignedRect(Qt::LeftToRight,Qt::AlignCenter,size(),
                                qApp->desktop()->availableGeometry()
                                )
            );
setWindowFlags ( Qt::CustomizeWindowHint | Qt::WindowTitleHint);
lineEditkeyboard = new Keyboard();

connect(ui->txt_Pass ,SIGNAL(selectionChanged()),this,SLOT(run_keyboard_lineEdit()));
connect(ui->txt_user ,SIGNAL(selectionChanged()),this,SLOT(run_keyboard_lineEdit()));

}

void FrmLogin::run_keyboard_lineEdit()
{
Qt::WindowFlags flags = windowFlags();

QLineEdit *line = (QLineEdit *)sender();
lineEditkeyboard->setLineEdit(line);
lineEditkeyboard->ui->lineEdit->setText(line->text());
if(line->objectName()=="txt_Pass")
{
    lineEditkeyboard->ui->lineEdit->setEchoMode(QLineEdit::EchoMode::Password);
}
else
{
    lineEditkeyboard->ui->lineEdit->setEchoMode(QLineEdit::EchoMode::Normal);
}

lineEditkeyboard->setWindowModality(Qt::ApplicationModal);
lineEditkeyboard->setWindowState(Qt::WindowActive);
lineEditkeyboard->raise();
lineEditkeyboard->show();

}

-------------- Keyboard Widget Code -----------------------------------

Keyboard.h

#include <QWidget>
#include <QtGui>
#include <QLineEdit>
#include <QPushButton>

namespace Ui {
class Keyboard;
}

class Keyboard : public QWidget
{
Q_OBJECT

public:
bool IsOnlyCharVar=false;
explicit Keyboard(QWidget *parent = 0);
void setLineEdit(QLineEdit * );
~Keyboard();
QPushButton *enterButton;
Ui::Keyboard *ui;

private slots:
void keyboardHandler();
void on_enterButton_clicked();
void on_lineEdit_returnPressed();

private:

QString outputText;
QLineEdit *outputLineEdit;

};

Keyboard.cpp

#include "keyboard.h"
#include "ui_keyboard.h"
#include <QtGui>
#include "QToolTip"

Keyboard::Keyboard(QWidget *parent) :
QWidget(parent),
ui(new Ui::Keyboard)
{
ui->setupUi(this);

this->setWindowFlags(Qt::WindowStaysOnTopHint);   

connect ( ui->Buttona, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonb, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonc, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttond, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttone, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonf, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttong, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonh, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttoni, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );    

connect ( ui->space, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );

outputText = "";
ui->lineEdit->setFocus();

}

void Keyboard::keyboardHandler()
{
QPushButton *button = (QPushButton *)sender();
QString inputText = button->text();

QToolTip::showText(button->mapToGlobal(QPoint()),inputText,button,button->rect(),300);

if (inputText == "Space")
{
    outputText += " ";
}
else if(inputText == "&&")
{
    outputText += "&";
}
else if(inputText == "\\")
{
    outputText += ui->Buttona->text() ;
}
else
{      
    {
        outputText += inputText;
    }
}
ui->lineEdit->setText(outputText);

}

void Keyboard::setLineEdit(QLineEdit * line)
{
outputLineEdit = line;
}

Keyboard::~Keyboard()
{
delete ui;
}

void Keyboard::on_shift_clicked()
{
if(shift == true)
{
shift = false;
ui->shift->setStyleSheet("background-color: rgb(248, 248, 248);");

    ui->Buttona->setText("a");
    ui->Buttons->setText("b");
    ui->Buttond->setText("c");
    ui->Buttonf->setText("d");
    ui->Buttong->setText("e");
    ui->Buttonh->setText("F");
    ui->Buttonj->setText("g");
    ui->Buttonk->setText("h");
    ui->Buttonl->setText("i");
}
else
{
    shift = true;
    ui->shift->setStyleSheet("background-color: rgb(121, 121, 255);");
    ui->Buttona->setText("A");
    ui->Buttons->setText("B");
    ui->Buttond->setText("C");
    ui->Buttonf->setText("D");
    ui->Buttong->setText("E");
    ui->Buttonh->setText("F");
    ui->Buttonj->setText("G");
    ui->Buttonk->setText("H");
    ui->Buttonl->setText("I");
}

}

void Keyboard::on_clear_clicked()
{
outputText="";
ui->lineEdit->setText(outputText);
}

void Keyboard::on_enterButton_clicked()
{
//qDebug() << "enter";
outputLineEdit->setText(outputText);
outputText="";
ui->lineEdit->setText(outputText);
close();
}

void Keyboard::on_backButton_clicked()
{
//outputText.remove(outputText.length()-1,outputText.length());
outputText.remove(outputText.length()-1,1);
ui->lineEdit->setText(outputText);
}

Arvind K

Any Updates??
Please feel free to ask any questions on above code.

mrjj

@Arvind-K
Hi
What did
qDebug() << "focus widget " << qApp->focusObject();
report ?
in the case where it dont type.

Arvind K

@mrjj

i used qDebug() << "focus widget " << qApp->focusObject(); at button click event.

it doesn't fire at first time . but at second time click on Button "a" i get "focus widget QPushButton(0x26bbc00, name= "Buttona")" log .

i think at first time my keyboard widget doesn't get activate. after click on widget anywhere it gets activate and after that it works proper.

how to solve this issue.?

J.Hilk

Hi,

from my experience, this behaviour comes from the focus shift,

you click a button and than it gets the focus a and only than the clicked mechanimn works.

IIRC, you can change that a couple of different ways.

the following comes to my mind:

Chaning the signal from clicked to released
Subclassing QPushButton and manually emitting the pressed signal during focus in event

Arvind K

@J.Hilk

Thank you for your reply.

At the first time my Push button click event is not getting fired so released event is also not working.
I have implemented focus in event but at first time its also not getting emitting.

mrjj

@Arvind-K
Hi
for my keyboard, I find it needed to have
NoFocus for focusPolicy on the buttons or they steal focus from Lineedit.

Arvind K

still, the issue is pending. Please provide a solution.

JoZCaVaLLo

It may be a silly question, does it happen with all the buttons of your keyboard?
Are you sure that the first time you push on a button of your keyboard the slot keyboardHandler() gets called?

Arvind K

@JoZCaVaLLo

Yes, it happens with all the buttons of a keyboard. slot keyboardHandler() does not get called for the first time. another thing I observed that when I called a keyboard on QPushbutton clicked event then keyboard works properly. this issue happens with QlineEdit Only.

JoZCaVaLLo

I would call lineEditkeyboard->setLineEdit(line) only when the lineEdit gets the focus.
In addition, in the setLineEdit(), I would call this->setFocusProxy(line). In order to avoid your keyboard to steal the focus from your linedit.

Arvind K

@JoZCaVaLLo
@mrjj
@J-Hilk
@dheerendra
one more thing to share when I called keyboard widget with a show() like
lineEditkeyboard->setLineEdit(line);
lineEditkeyboard->show();

the keyboard works properly but when I called Keyboard like

lineEditkeyboard->setLineEdit(line);
lineEditkeyboard->setWindowModality(Qt::ApplicationModal);
lineEditkeyboard->show();

then I face the same issue of the first click.

mrjj

@Arvind-K
hi, we need to find out what is happening.
please do
qDebug() << "focus widget " << qApp->focusObject();
which tells us when you open the keyboard, who has focus.
Meaning who will get the keys if u type.
I think you have something that steals keyboard focus when u open the
lineEditkeyboard

Arvind K

@mrjj

as you said I have done same when keyboard widget is shown.
output is

DBG default: focus widget QLineEdit(0x227ca90, name = "lineEdit")

lineEdit is Nothing but the QLineEdit on Keyboard widget.

mrjj

@Arvind-K
Ok so it does have the focus when first click is not registered?

Arvind K

@mrjj

Yes.
after that when I click on Anywhere on Widget Nothing happen or no Any event gets called.

mrjj

@Arvind-K
so the widget appear frozen for a moment ?
Do you have any kind of loops in constructor or anything like that ?

Arvind K

@mrjj

No, there is no Loop in the constructor or No Any other code only I have connected signal to Slot.

Keyboard::Keyboard(QWidget *parent) :
QWidget(parent),
ui(new Ui::Keyboard)
{
ui->setupUi(this);

this->setWindowFlags(Qt::WindowStaysOnTopHint);
connect ( ui->Buttonq, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonw, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttone, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonr, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttont, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttony, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonu, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttoni, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttono, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonp, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );

connect ( ui->Buttona, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttons, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttond, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonf, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttong, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonh, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonj, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonk, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonl, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonz, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonx, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonc, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonv, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonb, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonn, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Buttonm, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Button0, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Button1, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Button2, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Button3, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Button4, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Button5, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Button6, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Button7, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Button8, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->Button9, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );
connect ( ui->space, SIGNAL( clicked() ), this, SLOT( keyboardHandler() ) );

outputText = "";
shift = false;

}

mrjj

@Arvind-K
ok. when this situation is happening.
Does the buttons show activated effect ?
I mean can u see u pres them or anything ?

Arvind K

@mrjj

As I mentioned Previously when I set WindowModality of Keyboard widget to QApplicationModal I face this First Click issue otherwise it works fine. but if I didn't set windowModality then Keyboard goes back to the parent widget.

**lineEditkeyboard->setWindowModality(Qt::ApplicationModal); **

mrjj

Hmm.
The code looks ok fine and i cant see any reason for
QApplicationModal to cause this effect but
it could be a bug in Qt.

Arvind K

@mrjj

I can't see press button effect for the first time.

mrjj

@Arvind-K
Ok, then it seems its stuck for a moment in the event loop.
Im not sure what to do about that.
setWindowModality(Qt::ApplicationModal) must use a local even loop to make
it modal so might be a but with this or something i dont see in the code.

Important: Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

Custom QWidget Keyboard first time click issue.

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