I have a program that will act as a network-linked visualizer for a hardware system with no screen (think RaspberryPi). I currently have a QTabWidget with around 45-50 QPushButtons and textboxes (for numbers), but I'm bothered by the amount of connect statements I'll have to make. Is there a better way to make this many buttons? I've seen methods for using an array, but nothing with using a QTabWidget and the only thing I saw on that was creating a form.
I'm sorry I can't give you a proper answer with code. I have no proper internet so I have to do this on a phone.
Set up an array of buttons, maybe even a custom class derived from QPushButton with a signal that includes an identifier for the button, such as std::string name. You can then run a loop assigning your connects with something like:
connect(buttonArray[x], SIGNAL(buttonIsPushed(std::string) ), receivingObject, SLOT(buttonWasPushed(std::string)))
Of course this may be of little help if the receiving object has to pass on the signal as a signal.
Related
this is my first question on this website, but I will try to cover everything that is needed. Apologies if I forgot something. I encountered the problem using QT Creator, but I suppose it would be the same using Visual Studio, or just C++ in general.
I've got a couple of classes: Mainwindow, Track and AddForm. Mainwindow is what it is called. The main form. Track is a custom class based on QObject which contains just a single QString variable (just for now, since I am still experimenting with QT). And AddForm is a class for another form that can be created by clicking a button in my MainWindow form. That form only contains a single line-edit to fill the string and a button that says "Add". Whenever that button is pressed the text from the line-edit will be put into the QString variable from the Track-class. That QString variable is called "artist".
Apart from assigning the text from the line-edit to the variable "artist" for the Track-object, the form will also emit a signal that sends that entire object. A slot within my mainwindow will react to that signal and collect the Track-object. So far so good.
Here is my question. Within my mainwindow-header I have created a private QVector named trackVector, which I can then call within my mainwindow.cpp. What I want to do is append / push_back the QVector with that Track-object. Sort of like this:
trackVector.push_back(trackObject);
I get the following error message when building the application:
click here for a screenshot
Now ofcourse with an integer or any other variable this is very straightforward. You would just do something like this I suppose:
QVector<int> myVector;
myVector.push_back(3);
I think that whenever you append a QVector (or a standard non-QT vector) you need to do so with the constructor of that class. But how can I make a constructor in which you can just put an already existing object?
Please explain with as much simple words as possible since I am no native English speaker :) Thanks a lot in advance!
You've posted insufficient code (so your post is liable to be closed as off topic -- a classical beginners error on SO), but I guess the appropriate solution here is to use some auto pointer type. If your TrackVector is to keep ownership of the Track objects, then the best solution is have std::unique_ptr<Track> elements:
std::vector<std::unique_ptr<Track>> TrackVector;
// filled like
TrackVector.emplace_back(new Track(args));
If, on the other hand ownership lies somewhere else, you may either use std::shared_ptr or even raw pointers (provided your layout guarantees that the pointed to Track objects' lifetime exceeds that of the TrackVector).
I'm rather new to C++, I have a bit of experience with MCV programming in Java. im using GTKmm on C++
What I'm trying to do is writing an application for teaching assistants to submit and edit applications to various positions, and administrators to come in view, and accept these applications.
What I'm trying to do at the begging is create 3 'frames' (I'm working on the submitting application for students only at the moment)
This first will have 2 buttons 1 for selecting if you're a student/admin
Upon clicking you're a student I want to hide this frame and show my second frame
The second frame will have another 2 buttons one for creating an application, and the other for editing applications
My core problem is that I don't understand how to switch between the frames, I've written all the code for my Model, and understand everything I want it to do however I cant seem to find how to do this...
My only idea would be to create windows for each of these, make them look all nice w/e, then when a button is pressed have that window close and a string written to file I can access to see which button has been pressed, then open a new window accordingly. Should I do it like this or is there a better way?
I think I can suggest a better/more idiomatic option for any version >= GTK+ 3.10 - which, to be fair, arrived about half a year after the accepted answer.
If you want to switch between widgets one-at-a-time without any accessories like tabs, then a Gtk::Stack seems like a better option. Because it's specifically geared for one-at-a-time presentation, without any redundancy and (theoretical) overhead from a Notebook's manual tabbing features, which you'd just be disabling straight away! It's a container with multiple children, with one visible at any given moment, and of course methods to change the active child.
You can hook up your own widgets and/or events to manage which of the Stack's children is shown. Alternatively - albeit possibly just restoring the redundancy in this case - there's a StackSwitcher companion widget, which is pretty much a vertical tab-bar as seen in the GTK+ demo and GNOME Tweak Tool.
Easiest way is to use a Notebook widget. You can hide the tabs since you will be controlling which page is showing, using method set_show_tabs(false). Put the top level widget for each of your frames in a pane using method append_page(), and switch between them using set_current_page(). You might want to hide the notebook's bevel if it's distracting, using method set_show_bevel(false).
Use signals to make a widget (e.g. "I'm a student" button) on one page do something (e.g. go to the second page). If you don't know what this means or how to do it, go through the gtkmm tutorial, it will explain this and more.
A bit too late ! But here is my try :
Gtk::Notebook is great but it is not ideal in switching between app frames on menu item clicks. Gtk::Stack, since gtkmm 3.10, exists to mitigate this. Assuming you're using glade and Gtk::Builder :
class
class AppName : public Gtk::ApplicationWindow
{
public:
//...Your app methods and callbacks
void on_mb_itemname_selected(); // The call back for our menu item click/select
private:
//Builder which will help build the app from a .glade file
Glib::RefPtr<Gtk::Builder> _builder;
//...
//Your menu item to activate a particular frame
Gtk::MenuItem * _mb_itemname;
//Your handle to Gtk::Stack which is usually the stack for the whole app
Gtk::Stack * _app_stack;
//...
}
constructor
AppName::AppName(BaseObjectType *cobj,
Glib::RefPtr<Gtk::Builder>& ref_builder)
:Gtk::ApplicationWindow(cobj),_builder(ref_builder)
{
//.. Other setup
_builder->get_widget("your_glade_id_to_stack",_app_stack);
_builder->get_widget("your_glade_id_to_menu_item",_mb_itemname);
// Connect signal_select of our menu item to appropriate signal handler.
mb_itemname->signal_select().connect(
sigc::mem_fun(*this,&AppName::on_mb_itemname_selected));
}
our callback
void AppName::on_mb_itemname_selected()
{
// Change the visible child of the stack concerned.
Gtk::StackTransitionType ttype = STACK_TRANSITION_TYPE_NONE;
_app_stack->set_visible_child("your_widget_name",ttype);
// Note that widget name is not widget glade id.
// You can set your widget under name Packing -> Name
return;
}
In our application, we have a variable number of dockwidgets because some of them are added by plugins that are loaded at runtime. Not all dockwidgets need to be visible at the same time necessarily. This depends strongly on what the user is working on and what plugins are active.
However, if too many dockwidgets are added programmatically with addDockWidget(...), they start to overlap each other (not in terms of tabs, but in terms of content of one being painted on the area of a different one, which obviously looks broken).
The user can move the dockwidgets to dockareas that still have space left, but the layout/main window successfully prevents (untabbed) re-addition to the "crowded" dockarea.
We do allow tabbed docks to allow the user to arrange the dockwidgets a required, but we don't want to enable QMainWindow::ForceTabbedDocks since this would constrain the number of simultaneously visible dockwidgets too much (one per dock area).
How can I prevent this or better control how dockwidgets are added?
Not answering your question directly but it might be worthwhile to actually forget about Qt and actually think of how the whole interaction should work. What are the user expectations? What should actually happen if 10 different plugins become active? Should they be docked or should they be floating or should they become pin-able docking windows with initial state as a small button on the MainWindow edges? I think once you do that ground work and come up with user interface mock-ups, you can then start looking at Qt and figure out if Qt provides a direct way to develop that interface and if not what additional components you will need to develop to get that interface working.
From my own experience, I had developed a similar interface long back but in MFC. The way we did it was that some of the docked windows were deemed to be must have and they would come up as docked. Then there were a set of windows that didnt need to be visible always but should be quickly available and their initial state was as hidden pin-able dock window which meant they came up as buttons on the MainWindow edge. Finally there was a third set that was not required by the user always and could be called in from File->View Menu. Once the user made it visible, the user typically would assign it to one of the first two groups or keep it afloat. This whole configuration was saved in a config file and from there onwards whenever the plugin was loaded/became active the last used state of the associated docking window was used. It though involved quite a bit of extra work but the end result was to the satisfaction of all users.
Have you tryed setDockOptions(QMainWindow::AllowNestedDocks)? I can't test it now but it may help.
By default, QMainWindow::dockOptions is set to AnimatedDocks | AllowTabbedDocks so you would want something like
setDockOptions(QMainWindow::AllowNestedDocks | QMainWindow::AnimatedDocks | QMainWindow::AllowTabbedDocks)
EDIT:
If you are having too many problems, you may be going about this the wrong way. Instead of using docks, you may want to try using QMdiArea with QMdiWindow. This may not work for your program, but its something to think about.
This is the solution I tried:
I created in QTCreator an empty project with a window, a minimalistic menu labelled "New Dock" and a DockWidget named dockWidget
This is the triggered() handler for my menu item:
void MainWindow::on_actionNew_Dock_triggered()
{
QDockWidget* w = new QDockWidget("Demo", ui->dockWidget);
this->addDockWidget(Qt::LeftDockWidgetArea,w);
this->tabifyDockWidget(ui->dockWidget,w);
}
tabifyDockWidget(QDockWidget* first, QDockWidget* second) is a QMainWindow method that stacks the second dockwidget upon the first one. Hope it helps...
I am creating a GUI to manipulate a robot arm. The location of the arm can be described by 6 floats (describing the positions of the various arm joints.
The interface consists of a QGraphicsView with a diagram of the arm (which can be clicked to change the arm position - adjusting the 6 floats). The interface also has 6 lineEdit boxes, to also adjust those values separately.
When the graphics view is clicked, and when the line edit boxes are changed, I'd like the line edit boxes / graphics view to stay in synchronisation.
This brings me to confusion about how to store the 6 floats, and trigger events when they're updated. My current idea is this:
The robot arm's location should be represented by a class, RobotArmLocation. Objects of this class then have methods such as obj.ShoulderRotation() and obj.SetShoulderRotation().
The MainWindow has a single instance of RobotArmLocation.
Next is the bit I'm more confused about, how to join everything up. I am thinking:
The MainWindow has a ArmLocationChanged slot. This is signalled whenever the location object is changed.
The diagram class will have a SetRobotArmLocation(RobotArmLocation &loc). When the diagram is changed, it's free to change the location object, and fire a signal to the ArmLocationChanged slot.
Likewise, changing any of the text boxes will fire a signal to that ArmLocationChanged slot. The slot then has code to synchronise all the elements.
This kind of seems like a mess to me, does anyone have any other suggestions? I've also thought of the following, does it have any merrit?
The RobotArmLocation class has a ValueChanged slot, the diagram and textboxes can use that directly, and bypass the MainWindow directly (seems cleaner?)
thanks for any wisdom!
Except for really simple cases (e.g. a label that shows the value of a slider) my experience has been to stay away from inter-component signal/slot connections inside Qt Designer. Rather, have the component firing the signal of interest connect to a slog defined in the top level QWidget class you're subclassing (i.e. QMainWidow, etc... let's just call it the Form class). You can also go the other way: if you have a custom signal in the Form class, you can connect it with Qt Designer to one of the public widget slots.
To be specific using your example:
I'm going to assume that you have subclassed QMainWindow and QGraphicsView. Let's call the subclasses RobotMainWindow and RobotView.
RobotMainWindow contains the QLineEdit fields and RobotView. The way you specify RobotView in Qt Designer is to insert a QWidget and use the Promote to... feature to tell Qt that the QWidget should be replaced at compile time with your custom RobotView.
Name the QLineEdit fields edit1, edit2...edit6.
In the Qt Designer signal/slot editor define slots in RobotMainWindow to be called when the value in a QLineEdit changes. There are some more elegant ways of doing this, but for simplicity let's say you define 6 slots named setValue1(float), setValue2(float), etc.
In the source code for RobotMainWindow, go declare and define these slots, such that they update your arm, shoulder, whatever.
Also in the source code, define a signal valueChanged() (or multiple for each field, your choice). Have the slots you defined emit valueChanged().
Back in Qt Designer you can now link the appropriate signal from each QLineEdit to the corresponding slot in RobotMainWindow.
Back in the signal/slot editor add the valueChanged() signal to the RobotMainWindow (so Qt Designer knows about it). Connect this signal to a new slot in RobotView, using the procedure above, so it can update the rendering.
Repeat all of this for handling changes from RobotView to the editing fields (via RobotMainWindow.
In short, I think you'll find everything more straight-forward if your route the signals through your Form subclass (which I think of as the Controller in MVC parlance).
I am currently writing a wizard-style application using Qt4. I am not using the wizard class however, since going next/back does not make sense from every step in the process.
The user starts off at a "hub"-window with five buttons, each of which take him to another window at a different stage of the process. At the beginning all but the first button of the hub are disabled. After clearing each stage, the user will be directed back to the hub and one new button/stage will get enabled.
Since every stage has significantly differing objectives, I coded every single stage as a single QWidget that gets instantiated in the main() function. To switch between the widgets, I simply hide() the one I am leaving and show() the one I am going to.
However, this leads to problems if the user resized or moved one widget, since the next widget will always show up at its default position instead of the new one.
Is there a way to synchronize the widgets' sizes and positions?
Or, better yet, is there a more elegant way to deal with those different windows than switching between several hidden widgets?
Thank you in advance!
Create one top-level widget that holds the others.
I suggest that you either use QStackedWidget, or, if you want more control, create your own widget and use QStackedLayout directly.
Why not just have one main QWidget as a container for your pages? That way if the user moves the main QWidget and then goes to the next page, it will still open in the new position inside the main widget.
Generally, I've never had occasion to create multiple widgets inside my main method. Don't quite see the point.
I'm beginning on something similar - with different views (perspectives) for different tasks along the way. Using toolbar icons and file menu, not buttons, to move between views. Similar to how MS Outlook allows you to have the window display email, or a calendar, or contacts, etc.
My intent (haven't started yet) is to have one QMainWindow as the application window, containing my various QWidgets that offer the various views. Depending on what task the user is doing, one composite widget will be visible, and the others hidden.