How can i access ui files of children of a class. Lets say MainWindow class has twoa child dialog. I want to access LINEEDIT of dialog so that i can take text from there. Similarly how can i access ui files of parent inside child class in QT. Note: I havn't inherited any thing from Parent class.
I have writen the following code, in order to display a dialog but it won't show!
void MainWindow::displaydialog()
{
ItemDialog dialog= new ItemDialog(this);
dialog->show(); // it is not displaying the dialog
}
and how can i access the ui widgets like check whether ListWidget item has been selected or not.
Here is the code of itemdialog,
#include "itemdialog.h"
#include "ui_itemdialog.h"
#include "mainwindow.h"
ItemDialog::ItemDialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::ItemDialog)
{
ui->setupUi(this);
setWindowTitle("Status Dialog");
setFixedSize(QWidget::sizeHint());
}
ItemDialog::~ItemDialog()
{
delete ui;
}
void ItemDialog::on_pushButton_clicked()
{
MainWindow obj;
obj.okbuttonclicked(ui->lineEdit->text());
}
Please review an example such as this: http://qt-project.org/doc/qt-4.8/designer-using-a-ui-file.html
It explains how to use the ui files that you generate from Qt Designer. You shouldn't really think of them as "ui files" in the sense of accessing them on the widgets in your class. The idea is that you include them, and then use their setupUi() function to apply them to your given class. At that point, everything you created in qt designer, and that is in that ui file, is now a member of your class. They can be accessed via the naming you used in qt designer.
As for why your dialog isn't showing...I don't know because you only included 3 lines of code as an example. Theoretically it should show if Mydialog was properly set up. You could just try changing it to a QDialog to make sure you didn't do anything wrong with your custom class.
It depends what you want that dialog for. Either it's a modal dialog - some kind of a information display or retrival that blocks the function of your program until user reacts, or it's somekind of toolbox or similar, in which case you probably should not use QDialog.
If a modal dialog with a line edits and/or additional features is what you want, you should read up on QDialog in the doc. See the exec() function. Basic usage would go like this:
void MainWindow::displaydialog()
{
ItemDialog *dialog = new ItemDialog();
if (dialog->exec() == someApropriateReturnStatus)
{
QString somevalue = dialog->someValue();
int dialog->someOtherValue();
//do something with the value
}
delete dialog;
}
The point is that the ItemDialog class handles the UI internally and implements the getter functions accordingly, you should not (in most typical cases) access it's UI from outside.
If a simple line edit is all you want, you'd be better off using one of the standard dialogs already implemented in Qt, have a look at the Standard Dialogs Example
Related
I'm looking to generate a set of labels and buttons based on some kind of template, but I don't know how to do the template part.
I'll be using a tab widget which I already have set up, and in one the tabs, I want to have a two labels, a custom button, and a textbox. It'll be repeated around 40-50 times (dependent on a given value at startup) and have spacing as needed.
Once I have a template, I foresee calling it in a loop and setting the appropriate displayed text(Label_1, Label_2, etc) and connect statements where needed.
As I said, I don't know how to template parts of the UI so they can be placed in a kind of auto-generation.
I had thought of making one group, copying the xml, and somehow adding it but that doesn't seem to be a proper way. A little new to Qt.
This is roughly the layout I want to repeat. It has two labels, a lineedit, and one pushbutton.
There's no "good" way to do this in QtDesigner/QtCreator. At best you could copy/paste the set of controls 50 times and then in C++ code hide the ones you don't need. But I wouldn't recommend this.
Instead, just create the controls (labels/button/text box), and a layout to hold them, in C++ code, inside a loop which iterates however many times you need at runtime. Insert the controls layout into the tab widget page layout which you have set up in designer mode. It is not difficult, and will actually be more efficient than what QtDesigner produces since that tends to generate more code than you typically need in the first place.
As a starting point, you could look at the C++ code which is generated by the Qt UI Compiler (UIC) tool for your current design (it takes the XML from designer and turns it into C++ code). You can find this in the build folder for your project, typically named something like ui_ClassName.h, probably in a ui subfolder of the build tree.
UPDATE:
Another, possibly better, way to do this is to create the "template" QWidget class/form, which is going to be used multiple times, as a separate object. The "template" design could be created/maintained using QtCreator/Designer (or just directly in C++). The (possible) advantage here is that as the app requirements evolve, the template widget can be expanded with additional functionality or even re-used in other parts of the UI.
For example, I'd assume the text editor and button in the given mockup image will actually need to do something (eg. edit data and submit it). So some basic functionality can be built into the "template" widget, for example to emit a signal with the text contents of the line editor when the button is pressed.
I put together a quick example. I'm creating the simple MainWindow in pure C++ to simplify/shorten the example code. The "template" I'm calling an Editor. The Editor class and UI form I initially created with the QtCreator wizard (New -> Qt Designer Form Class). I then added the label/control widgets in designer mode. And in C++, a textEdited(const QString &text) signal in the header, and in the Editor() constructor a lambda connection to emit that signal when the button is pressed.
The Editor class code is straight out of the QtCreator wizard except for two edits I'm highlighting below. The designer form has two relevant controls: a QLineEdit (lineEdit) and a QPushButton (pushButton). I'll link to the full files below.
Editor.h
// in the Editor class declarations:
signals:
void textEdited(const QString &text) const;
Editor.cpp
// in the constructor, after ui->setupUi(this);
connect(ui->pushButton, &QPushButton::clicked, this, [this]() {
emit textEdited(ui->lineEdit->text());
});
Test harness, including MainWindow subclass and main()
#include <QApplication>
#include <QMainWindow>
#include <QTabWidget>
#include <QBoxLayout>
#include <QMessageBox>
#include "Editor.h"
class MainWindow : public QMainWindow {
Q_OBJECT
public:
MainWindow() : QMainWindow()
{
// set up a tab widget as the window central widget
QTabWidget *tabWidget = new QTabWidget(this);
setCentralWidget(tabWidget);
// the first/only page will contain all the editors in a vertical layout
QWidget *editorsPage = new QWidget(this);
editorsPage->setLayout(new QVBoxLayout());
// add the editors container page to tab widget
tabWidget->addTab(editorsPage, tr("Editors page"));
// Now create a number of editor widgets using our Editor class "template"
int layoutItems = 5; // number of editors needed, could be dynamic
for (int i=0; i < layoutItems; ++i) {
// Create an Editor instance with the tab page as parent
Editor *editor = new Editor(editorsPage);
// Add the editor widget to the tab page layout
editorsPage->layout()->addWidget(editor);
// A simple connection with the editor signal, as way of example.
connect(editor, &Editor::textEdited, this, [this](const QString &text) {
// just show a message box with the editor text
QMessageBox::information(this, tr("Text Edited"), text, QMessageBox::Ok);
});
}
}
};
int main(int argc, char **argv)
{
QApplication app(argc, argv);
MainWindow mainWindow;
mainWindow.show();
return app.exec();
}
#include "main.moc"
Links The full Editor code:
Editor.h
Editor.cpp
Editor.ui
The XML in Qt Creator is for UIC in QMake to generator code for you.
For example, QMake translates your mainwindow.ui to ui_mainwindow.h, and within you will find void setupUi(QMainWindow *MainWindow) with the actual code that creates and places the widgets.
Look at this code, the docs, and create and place the widgets yourself by code.
For example, adding 5 checkboxes to a groupbox by code:
QVBoxLayout *l = new QVBoxLayout(this);
ui->groupBox_4->setLayout(l);
for(int i=0; i<5; i++){
QCheckBox *c = new QCheckBox(this);
l->addWidget(c);
}
I know this is very clunky and I'm probably doing a lot of wrong things but so far everything I saw on the net gives back the same errors: invalid use of non-static data member ui.
So in the MainWindow, I have a comboBox named hometeam, and I want to display the currentText on a Qlabel named label which is on another Form Class called Dialog
I figured they're both private members so I added friend class MainWindow and friend class dialog in the respective headers (I know this is pretty wrong but it's the last thing I tried), I included the "ui_mainwindow" and "ui_dialog" in the .cpp files, and here's the bit of code I'm trying:
ui->label->setText(MainWindow::ui->hometeam->currentTex());
Keep in mind that I don't want a QDialog, the second window will do a lot more than a display, I just want to access the objects from a different window. Slots and signals give the same error.
Thanks !
I think the proper way to do that, is to add a function to your MainWindow class:
QString hometeamText() const
{
return ui->hometeam->currentTex();
}
This way you can access the information you need without violating encapsulation rules, but you need an instance of MainWindow to do it, and sure must keep a pointer to it in your Dialog class:
class Dialog
{
private:
MainWindow * mainwindow;
public:
void setMainWindow(MainWindow * w) { mainWindow = w; }
then somewhere (e.g. in main) you can do something like:
MainWindow mainwindow;
Dialog dialog;
dialog.setMainWindow(&mainWindow);
and from inside your Dialog class, wherever you need it:
ui->label->setText(window->hometeamText());
This is my first question here, so I'm trying to not sound stupid!
EXPLANATION:
I have a main window in Qt that has a button to create (sub-?) windows within the main window. This can be done as many times as the user wants, and each sub-window displays the same set of properties/items. I figured writing a class to hold all these properties would be a smart way to go about it (this would inherit the main window class), as each instance of the child window would automatically get the properties. I am using a slot to create each instance.
QUESTION:
Besides the desired properties, what do I add to the child window class to let Qt know that if I create an object of that type it should open a window?
For example, say I have implemented all the child window properties in a header file that looks something like this:
#include <QObject>
#include <QDialog> //Not sure about this
class ChildWindow : public ParentWindow
{
Q_OBJECT
public:
ChildWindow(QObject* parent);
~ChildWindow();
//Remaining properties like QSpinBox, Radio buttons etc
}
how then would I implement my slot? Like this?
void Parent::Slot()
{
ChildWindow* window;
window = new ChildWindow(this);
window->show()
}
My problem is that I don't see any code that indicates that window is a separate window. I can see that it is of type ChildWindow, but does just including QDialog give it the show() functionality?
EDIT:
I realise the first suggestion would be try and see if this works, but in the unlikely scenario that it works I wouldn't have learnt anything and I still wouldn't know why it worked, and if it didn't I would be back here asking this same question. I hope you guys understand.
EDIT 2:
error C2039: 'show' : is not a member of 'ChildWindow'
So I am guessing including QDialog did not do the trick
EDIT 3:
If I add this to the ChildWindow constructor
QDialog* child;
child = new QDialog;
child->show()
Do I have to do the same in the slot definition as well?
I've created a qt widgets application. Using the design mode I've created a QTextEdit and indicated that in the header file:
...
QT_BEGIN_NAMESPACE
class QAction;
class QMenu;
class QTextEdit;
QT_END_NAMESPACE
...
private:
Ui::MainWindow *ui;
QTextEdit *textEdit_2;
};
There is also a slot which is triggered by pushing a button. What it has to do is to insert some text into textEdit_2 after the button is pushed, still the program crashes.
In mainwindow.cpp:
void MainWindow::on_action_4_triggered()
{
textEdit_2->setText("text");
}
I've also tried
textEdit_2->setText(QString("text"));
which anyway doesn't work. What's the problem?
textEdit_2->setText("text");
The problem is that you are trying to ignore the actual text widget created in QtDesigner and invent another as a class member. This is not going to fly as you seem to want it.
In order to reuse the text widget from the UI that you created with the graphical tool, you would need to reuse the ui object as follows:
ui->textEdit_2->setText("text");
Please also note that you do not need to construct QString explicitly like this:
textEdit_2->setText(QString("text"));
This will be all automatic for you.
I want to make a simple 'About' modal dialog, called from Help->About application menu. I've created a modal dialog window with QT Creator (.ui file).
What code should be in menu 'About' slot?
Now I have this code, but it shows up a new modal dialog (not based on my about.ui):
void MainWindow::on_actionAbout_triggered()
{
about = new QDialog(0,0);
about->show();
}
Thanks!
You need to setup the dialog with the UI you from your .ui file. The Qt uic compiler generates a header file from your .ui file which you need to include in your code. Assumed that your .ui file is called about.ui, and the Dialog is named About, then uiccreates the file ui_about.h, containing a class Ui_About. There are different approaches to setup your UI, at simplest you can do
#include "ui_about.h"
...
void MainWindow::on_actionAbout_triggered()
{
about = new QDialog(0,0);
Ui_About aboutUi;
aboutUi.setupUi(about);
about->show();
}
A better approach is to use inheritance, since it encapsulates your dialogs better, so that you can implement any functionality specific to the particular dialog within the sub class:
AboutDialog.h:
#include <QDialog>
#include "ui_about.h"
class AboutDialog : public QDialog, public Ui::About {
Q_OBJECT
public:
AboutDialog( QWidget * parent = 0);
};
AboutDialog.cpp:
AboutDialog::AboutDialog( QWidget * parent) : QDialog(parent) {
setupUi(this);
// perform additional setup here ...
}
Usage:
#include "AboutDialog.h"
...
void MainWindow::on_actionAbout_triggered() {
about = new AboutDialog(this);
about->show();
}
In any case, the important code is to call the setupUi() method.
BTW: Your dialog in the code above is non-modal. To show a modal dialog, either set the windowModality flag of your dialog to Qt::ApplicationModal or use exec() instead of show().
For modal dialogs, you should use exec() method of QDialogs.
about = new QDialog(0, 0);
// The method does not return until user closes it.
about->exec();
// In this point, the dialog is closed.
Docs say:
The most common way to display a modal dialog is to call its exec() function. When the user closes the dialog, exec() will provide a useful return value.
Alternative way: You don't need a modal dialog. Let the dialog show modeless and connect its accepted() and rejected() signals to appropriate slots. Then you can put all your code in the accept slot instead of putting them right after show(). So, using this way, you wouldn't actually need a modal dialog.