Dynamic FOrms

[BalaQT]

hi,
im new to QT programming,
i want to create DYANMIC form based on DATABASE
for ex:
sqlite table contains how many forms to create and size of the form
QT should connect sqlite table and it should create the forms

pls guide me

Bala

[wysota]

So what's the question?

[BalaQT]

wysota> Thnks for replying me
my question is :
i) how to create forms from QT by reading from SQLITE table

following is the code im using to show one window.

#include <QApplication>
 #include <QGridLayout>
 #include <QPushButton>
 #include <QTextBox>
 #include <QProcess>
 #include "Connection.h"
 #include <QtCore/QVariant>
 
 int main(int argc, char *argv[])
 {
        QApplication app(argc, argv);
        QWidget *win1 = new QWidget;
        QGridLayout *layout = new QGridLayout;
        QPushButton *ClickButton=new QPushButton("Click");
        QPushButton *CancelButton=new QPushButton("Cancel");
        QObject::connect(ClickButton,SIGNAL(clicked()),&app,SLOT(quit()));
        if(!createConnection())
                return 1;
        QSqlQuery q;
        q.exec("SELECT * FROM ConfigTable");
        q.next();
        win1->setWindowTitle("Window1");
        win1->setFixedHeight(q.value(2).toInt());
        win1->setFixedWidth(q.value(3).toInt());
        layout->addWidget(ClickButton,0,0);
        layout->addWidget(CancelButton,0,2);
        win1->setLayout(layout);
        win1->show();
        return app.exec();
}

#include <QApplication>
 #include <QGridLayout>
 #include <QPushButton>
 #include <QTextBox>
 #include <QProcess>
 #include "Connection.h"
 #include <QtCore/QVariant>

 int main(int argc, char *argv[])
 {
        QApplication app(argc, argv);
        QWidget *win1 = new QWidget;
        QGridLayout *layout = new QGridLayout;
        QPushButton *ClickButton=new QPushButton("Click");
        QPushButton *CancelButton=new QPushButton("Cancel");
        QObject::connect(ClickButton,SIGNAL(clicked()),&app,SLOT(quit()));
        if(!createConnection())
                return 1;
        QSqlQuery q;
        q.exec("SELECT * FROM ConfigTable");
        q.next();
        win1->setWindowTitle("Window1");
        win1->setFixedHeight(q.value(2).toInt());
        win1->setFixedWidth(q.value(3).toInt());
        layout->addWidget(ClickButton,0,0);
        layout->addWidget(CancelButton,0,2);
        win1->setLayout(layout);
        win1->show();
        return app.exec();
}

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How to create more than one windows, if the ConfigTable contain 2 or more records?

Thnks
Bala

[wysota]

I don't see a problem... just use a for() loop and in each iteration create a widget, fill it with child widgets and show it. Alternatively you can use QUiLoader if you can afford storing ui files in the database.

[BalaQT]

Sir, thnks for the reply,
i got the logic. but dont know how to do it in QT coding. pls provide me source code with for loop to create child widgets

Thnks
Bala

[wysota]

How can I provide code if I don't know what the database holds?

[BalaQT]

Table Details
Database : SQLITE
Table Name : ConfigTable
Fields :
FormId Numeric
FormName Text
FormHeight Numeric
FormWidth Numeric

ConfigTable location : E:\Bala\Ramana\DynamicForm\DynaBase

connection.h

#ifndef CONNECTION_H
#define CONNECTION_H
 
#include <QMessageBox>
#include <QSqlDatabase>
#include <QSqlError>
#include <QSqlQuery>
 
static bool createConnection()
{
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    //db.setDatabaseName(":memory:");
    //db.setDatabaseName("e:/BALA/hirola");
    db.setDatabaseName("e:/BALA/Ramana/DynamicForm/DynaBase");
    if (!db.open()) {
        QMessageBox::critical(0, qApp->tr("Cannot open database"),
            qApp->tr("Unable to establish a database connection.\n"
                     "This example needs SQLite support. Please read "
                     "the Qt SQL driver documentation for information how "
                     "to build it.\n\n"
                     "Click Cancel to exit."), QMessageBox::Cancel);
        return false;
    }
 
 
    return true;
}
#endif

#ifndef CONNECTION_H
#define CONNECTION_H

#include <QMessageBox>
#include <QSqlDatabase>
#include <QSqlError>
#include <QSqlQuery>

static bool createConnection()
{
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    //db.setDatabaseName(":memory:");
    //db.setDatabaseName("e:/BALA/hirola");
    db.setDatabaseName("e:/BALA/Ramana/DynamicForm/DynaBase");
    if (!db.open()) {
        QMessageBox::critical(0, qApp->tr("Cannot open database"),
            qApp->tr("Unable to establish a database connection.\n"
                     "This example needs SQLite support. Please read "
                     "the Qt SQL driver documentation for information how "
                     "to build it.\n\n"
                     "Click Cancel to exit."), QMessageBox::Cancel);
        return false;
    }


    return true;
}
#endif

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DynamicTable.Cpp

#include <QApplication>
 #include <QGridLayout>
 #include <QPushButton> 
 #include <QProcess>
 #include "Connection.h"
 #include <QtCore/QVariant>
 
 
 int main(int argc, char *argv[])
 {
        QApplication app(argc, argv);
        QWidget *win1 = new QWidget;        
        QGridLayout *layout = new QGridLayout;
        QPushButton *ClickButton=new QPushButton("Click");
        QPushButton *CancelButton=new QPushButton("Cancel");
        QObject::connect(ClickButton,SIGNAL(clicked()),&app,SLOT(quit()));
        if(!createConnection())
                return 1;
        QSqlQuery q;
        q.exec("SELECT * FROM ConfigTable");
        QString salary;
        q.next();
        win1->setWindowTitle("Window1");
        win1->setFixedHeight(q.value(2).toInt()); //FormHeight
        win1->setFixedWidth(q.value(3).toInt()); //FormWidth
        layout->addWidget(ClickButton,0,0);
        layout->addWidget(CancelButton,0,2);
        win1->setLayout(layout);        
        win1->show();
        return app.exec();
}

#include <QApplication>
 #include <QGridLayout>
 #include <QPushButton> 
 #include <QProcess>
 #include "Connection.h"
 #include <QtCore/QVariant>


 int main(int argc, char *argv[])
 {
        QApplication app(argc, argv);
        QWidget *win1 = new QWidget;        
        QGridLayout *layout = new QGridLayout;
        QPushButton *ClickButton=new QPushButton("Click");
        QPushButton *CancelButton=new QPushButton("Cancel");
        QObject::connect(ClickButton,SIGNAL(clicked()),&app,SLOT(quit()));
        if(!createConnection())
                return 1;
        QSqlQuery q;
        q.exec("SELECT * FROM ConfigTable");
        QString salary;
        q.next();
        win1->setWindowTitle("Window1");
        win1->setFixedHeight(q.value(2).toInt()); //FormHeight
        win1->setFixedWidth(q.value(3).toInt()); //FormWidth
        layout->addWidget(ClickButton,0,0);
        layout->addWidget(CancelButton,0,2);
        win1->setLayout(layout);        
        win1->show();
        return app.exec();
}

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This is working fine for ONE ROW, ONE WINDOW.
how to create n windows, if n rows are in configtable.

Thnks
Bala

[wysota]

while(q.next()){
  QWidget *w = new QWidget;
  w->setWindowTitle(...);
  w->setWFixedHeight(q.value(2).toInt());
  ...
  w->show();
}

while(q.next()){
  QWidget *w = new QWidget;
  w->setWindowTitle(...);
  w->setWFixedHeight(q.value(2).toInt());
  ...
  w->show();
}

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[BalaQT]

Thnks wysota
it solved my problem.
im new to QT. I understand SIMPLE OR BASIC means not easy untill u familiar with it.
i love QT.but im a beginner. so pls consider me,even if i ask any dumb questions.

i)what is the command for position the forms (LEFT AND TOP)?

Thnks
Bala

[numbat]

w->move(x, y);

w->move(x, y);

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[BalaQT]

thanks wysota

its working fine, but i have more doubts in this

how can i access the created window's widgets?
for ex:
a form displayed with 2 line edits in it.
createLineedit is the function im using to create a lineedit.

createLineedit() will be called 2 times to create 2 lineedits;

hw can i access the values in it, when i press one pushbutton

the follwing code called frm main.cpp
createLineedit("id")
createLineedit("name");

How to take the values TYPED in id,name line edit ,when the user press Savepushbutton?

pls guide me

[BalaQT]

any experts pls reply me.

My need is i want to create dynamic widgets and dynamic forms..
Im successful in creating dynamic forms and dynamic widgets, but How can i access the widget's value's?

since all widgets have same name, i can able to take the latest value only
how can i access all the values?

pls guide me

Thanks
Bala

[numbat]

If you have saved the widgets in a list you can just access that list:

for (int i = 0; i < list.size(); i++)
  qDebug() << list[i].text();

for (int i = 0; i < list.size(); i++)
  qDebug() << list[i].text();

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If you haven't saved a list, you can get one from your top-level widget. This will get all line edits which you can then iterate as above.

QList<QLineEdit *> myEdits = parentWidget.findChildren<QLineEdit *>();

QList<QLineEdit *> myEdits = parentWidget.findChildren<QLineEdit *>();

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[BalaQT]

Thnks nimbut,
Its working.
one more doubt in connecting SIGNALS AND SLOT

For better understanding, i will explain my need.
im creating forms and lineedit,pushbutton,label DYNAMICALLY frm a DB.


void DynamicControls::createPushButton(QString Wstr,QString WTip,int x,int y)
{
pushButton=new QPushButton(Wstr);
pushButton->setToolTip(WTip);
layout->addWidget(pushButton,x,y);
}


This function will be called in CreateDynamicForm shown below:

void DynamicControls::CreateDynamicForm()
{
    QSqlQuery q1,q2;
    q1.exec("select * from FormMaster where FormVisible=1 order by FormId");
    while(q1.next())
    {
        tableName=q1.value(7).toString();
        q2.exec("select * from WidgetMaster where FormId=" + q1.value(0).toString() +  " and WVisible=1 order by RowNo,ColumnNo");
        while(q2.next())
        {
 if(q2.value(2).toString()=="lineedit")
            {
                createLineEdit(q2.value(3).toString(),q2.value(1).toString(),q2.value(6).toInt(),q2.value(7).toInt());
 
           else if(q2.value(2).toString()=="PushButton")
            {
                createPushButton(q2.value(3).toString(),q2.value(1).toString(),q2.value(6).toInt(),q2.value(7).toInt());
            }
        }
    }

void DynamicControls::CreateDynamicForm()
{
    QSqlQuery q1,q2;
    q1.exec("select * from FormMaster where FormVisible=1 order by FormId");
    while(q1.next())
    {
        tableName=q1.value(7).toString();
        q2.exec("select * from WidgetMaster where FormId=" + q1.value(0).toString() +  " and WVisible=1 order by RowNo,ColumnNo");
        while(q2.next())
        {
 if(q2.value(2).toString()=="lineedit")
            {
                createLineEdit(q2.value(3).toString(),q2.value(1).toString(),q2.value(6).toInt(),q2.value(7).toInt());

           else if(q2.value(2).toString()=="PushButton")
            {
                createPushButton(q2.value(3).toString(),q2.value(1).toString(),q2.value(6).toInt(),q2.value(7).toInt());
            }
        }
    }

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The CreateDynamicForm will be called in CONSTRUCTOR
i want to know hw to connect signals
ex:
if the created buttons name is SAVE , then my own slot UPDATEtable() has to be called..
how can i do it.

since its dynamic , im getting some err in the following connect
(frankly i dont know how to connect a dynamically created button into CONNECT())
QObject::connect(pushbutton, SIGNAL(clicked()),this,SLOT(updateTable1(IndxValue 1)));

since all the pushbuttons names are same, connect not working properly.

how to create a connect for dynamically created pushbuttons...

Bala

[wysota]

Come on, all the time you are facing strictly C++ issues. We don't teach C++ nor basics of programming here - get a decent book on C++ to learn about pointers.

As for your last problem - you are passing a value to the slot in the connect statement which is forbidden. See the FAQ section of this site.

[BalaQT]

hi,
Thnks wysota, i will surely study on it. but pls help me here.

a)I've managed to create dynamic buttons.
Now I am having a problem with being able to tell which button was pressed. The button objects are created at runtime and they're added to QList. How do I find out which button in the array was clicked?

ex: 5 buttons are created frm DB. (all are having same name pushbutton)
1)new , 2) save 3)del 4)view 5)exit

i want to perform particular actions according to button click.
how can i know which button was clicked?

Any suggestions?

Thnks
Bala

[nish]

what is the need of sending pms if you posted your topic here and getting replies?

there is a function sender() which you can call in a slot to check which object called that slot.

QList<QPushButton *> btns;
void createbuttons()
{
btns<<new QPushButton("abc",this)<<new QPushButton("abc",this)<<new QPushButton("abc",this);
connect all these buttons to a slot myslot();
}

void myslot()
{
QObject* o = sender();
if(o==btns[0]) etc...
}

[wysota]

how can i know which button was clicked?

I'd suggest using QSignalMapper.