I have created a form. I have many 2 push buttons. On clicking on a pushbutton I want to call another custom form. I am using only QtDesigner. I am NOT using QtCreator. Using QtCreator, there are so many examples on how I can do it. But using only QtDesigner 4 there are no examples. I have also tried creating a MainWindow and then having pushbuttons in that. I want to call a new pop up window when I click on a button (which is a custom form). I am using Eclipse CDT as the IDE. I have installed Qt plugin so that I can do both C++ and Qt development. The problem is I cannot use 'Form' to declare my custom form in header file of the mainwindow.
I read in few posts that this is not possible to do using only QtDesigner and also read it can be done using QObject::connect. Please can anyone help me to confirm if we can do it and if yes please can you provide me an example?
Yes, it's definitely possible with C++. You'll need to connect() pushbutton's clicked() signal with a slot in your first form:
connect(pushButton, SIGNAL(clicked()), this, SLOT(show2ndForm()));
The good place to connect is in your first form constructor.
In that slot just show your second form (for example, using QDialog::exec()):
void FirstForm::show2ndForm()
{
static SecondForm *form = 0;
if(!form)
form = new SecondForm(this);
form->exec();
}
You'll probably need to inherit your second form from QDialog to use this method and also create header and source files for your second form.
For modeless form instead of modal, use form->show() instead of exec().
This is not complete possible if you need to customize a slot, but for simple operation where the existing slots are available, you can just use the signal-slot edit as below.
You can select the receiver object and then the correponding slot. I am providing further screenshot to show it is done for customized slots as well.
Right click with your mouse in the middle of the main window and the change signals and slots
Select the change signals and slot option
Use the Add button to add a new slot
Click on the OK button to conirm it once you chose the desired name
In the signal-slot editor double click on the desired object's slot, and it will show the available slots including your new custom slot.
Select your custom slot and you are done from the designer parts. Do not forget to actually implement that in your C++ code.
If you do not need a custom slot, and a built-in will suffice, you can select that off-hand without the previous steps. Those are provided for completeness.
Related
I am currently working in Qt Designer and i am trying to make button change the index of QStackWidget with click signal.
I entered signal editor mode and connected Button to QStackWidget, This is what i got:
As you see in the picture, setCurrentIndex(int) is grayed out, If i choose any signal from QPushButton, there is nothing associated with changing page.
Sorted Question:
How can i change the page in QStackedWidget using a button? (In Qt Designer).
That is not possible directly with Qt Designer, because QButton click signal doesn't send any index or argument, and setCurrentIndex(int) need an argument to chose change the index.
You have to do it using signal/slot in C++ code, or use an other widget like QSpinBox which emit a signal with an integer argument.
I have made the ui using QT designer. Which has a textbox in main window in which user enters his name. i want to call function 'input' when the data entered by user is over.
but i cant find a way to link a textbox from ui designed using QT designer to a coded function form other class.
I guess signal and slots (in qt designer) can only link to components of the same window.
Again,
at the same time i want to store the name entered by the user in a char variable usr_nm[] in the same function input. I later want to display the name in a text browser with some other details in function output.(-->Input and output function are in same class.)
Do you have to define this in Qt Designer?
It seems to me it would be better if you simply used an auto-connection slot, for example:
on_textBoxName_textChanged() // I'm assuming you are using QTextEdit
{
ui->textBoxName->toPlainText(); // this returns text in QTextEdit as QString.
}
This uses auto-connection - see here.
I've made my first qt window. Now I'd like to make my first dialog, using qt. I have just finished creating the dialog, which is basically made of a QDialogButtonBox, and now I'd like to connect it to the window. I have two beginner's questions:
How can I retrieve how the dialog was closed (ok pressed or cancel pressed) from the window.cpp, which creates a new dialog, and then calls dialog->show() ?
Where and how to destroy the dialog pointer ?
If you use dialog->show() then I assume it's non-modal dialog.
If you have created QDialogButtonBox and connected its signals with accept() and reject() slots of your dialog as documentation shows, then your dialog will emit finished(int) and additionally accepted() or rejected() signals by which you can determine how it was closed.
If you need more customized behavior, then you can reimplement closeEvent(QCloseEvent *event) or create your own singnals.
If you need to delete your dialog you can use setAttribute(Qt::WA_DeleteOnClose, true);, which will delete instance on close.
you can use one flag, and signal and slot.
when put OK flag=1 , and when put cancel then flag=-1; and then use signal.
in in the window.h write code how to handle that flags with 1 simple slot.
for destroying the pointer you can use signal and slot in your Dialog and tell when user push
Ok, or Cancel , or exit (up- right (red cross)) go to slot in call the Destructer of dialog
and also you that you better set parent of dialog to window.
First Question:
When you want to show the dialog,just construct it,using myDialog *d = new myDialog(this)(the this pointer will make sure that you havn't to delete the pointer you created 'cause Qt will handle this if you specified the dialog's parent). And use d->exec() if you need a modal dialog, or d->show() to make it non-modal;
Second Question:
Once your specified the dialog's parent object, all u need is just use it and leave alone the memory managent,Qt will do this for you. Also you can use d->setAttribute(Qt::WA_DeleteOnClose,true) to make it destroy itself when it is closed.
Remember to link the QDialogButtonBox to your dialog's actions.
In my project I am using a custom circle-shaped button widget derived from the QWidget class. I have added several of these widgets to a parent widget.
When one of these custom buttons is clicked, how do I find out which one was clicked?
Adding custom button to parent widget:
void ShotViewCTRL::addShot(QString shotNanme)
{
ShotButton *btnShot=new ShotButton(this);
btnShot->shotName=shotNanme;
connect(btnShot,SIGNAL(Shot_Selected()),this,SLOT(SHOT_CLICKED()));
btnShot->CreateButton();
btnShot->show();
}
My parent widget is ShotViewCTRL (inherits from QWidget), the child widget is ShotButton (custom control, inherits from QWidget).
The control is working fine. It's sending sending to parent object. In my problem, I added the same custom control 10 times.
I need to find which control was clicked? Please help me find the solution.
I have referred to the Qt documentation to find the child widget, but I did't understand. Some sample code would be great.
QSignalMapper is what you are looking for. With QSignalMapper, you can add something like an Id (or even a pointer to the QButton itself) as additional data to the signal emittance and you have to adjust your slot so it takes additional data (ID or Pointer).
Then either distinguish in the slot itself by the id you give your objects some virtual function type() so you can distinguish with that or even try casting and catch errors (Tip: don't try the last method, it may work differently on different compiler).
You can use the QObject::Sender function to find which QObject sends the signal. Regarding the first warning in the doc, it's what you are searching for.
you specify different slots for different buttons with same signal.with that you can recognize the different button click
Currently Im using QT Creator which created UI file for view and I'm a QT starter.
There is a part I am curious is that how can i create another Class for, let say a GraphicView, so that I can send signal and slot to that class instead of the main form?
Side Question: why I can't edit Singal and Slot in other place than MainWindow in Edit Signal/Slot Mode? (the edit button is not activated if it's not MainWindow, so i have to use those default Signal) Let say i need to create a ToggleFullScreen() but the edit is gray out, how do I do it?
Adam is right.
But there are several ways to use a UI file in your application.
Have a look at http://qt.nokia.com/doc/4.5/designer-using-a-ui-file.html
For signal-slot specific question : see the link in Adam answer.
But, in summary, if you declare the Q_OBJECT macro in yours classes, you can communicate between those by signal-slot mechanism !
Signals and Slots
You have to create a derived class that inherits from QMainWindow if you want to add new signals or slots.