I've created simple application with the DevExpress.XtraCharts.ChartControl. To customize X-axis labels, I used CustomDrawAxisLabel.
But this event occurs twice during creation (once for all labels e.g. from 0 to 10 and one more time from 0 to 10) and 4 times when mouse moves.
How can i get it to occur only single time for all axis labels?
From: CustomDrawAxisLabel Event is fired when moving the mouse over the Chart ?
According to our documentation the
ChartControl.CustomDrawAxisLabel event is raised before drawing a
control. This means that if a control should be redrawn, this method
will be raised first. The parent form can force a control to be
redrawn even if it was not actually changed. In addition, you can
invalidate a control manually by calling the ChartControl method.
Please note that if you use any code that causes chart redrawing (
even indirectly ), this method will be raised, too.
Hope this satisfy your quest for finding for the reason.
Related
I've setup a goal and hooked it up to an event, but even if the event occurs, the goal's conversion counter stays at 0 as if it's not hooked up. Any idea what might be causing this?
Have tried waiting for 48+ hours but still stays at 0.
You've said 'Event Value Greater than 1' - Event Value is an optional goal field that may be used to store an integer; usually something financial.
In this situation, you're ignoring any Member Question Form submissions unless they have an Event Value of 2 or more.
If that's not deliberate then it's your problem - just leave that field blank instead and it should work.
I may have worked myself into a corner but this sounded to me like a good idea at the time.
I have been developing an interface that permits a user to modify settings of a robotic device, i.e. speed, directions, force, etc. with a very large series of options in the form of ComboBoxes. The problem is that there are about a thousand of these things, in sub categories. e.g. Speed category x1, x2, x3, Y1, y2, etc. So rather than create a thousand comboboxes in QT, I thought the good idea was to create one set of 50 (ish) and then provide a few button to switch between categories. So when the user selects speed QT, populates the comboboxes with the appropriate options, sets the style sheets and text for the labels etc. So it appears as though a dedicated page exists. Then if the user selects Direction, QT Writes the current index of each box to a dedicated array and then repopulates the boxes, labels etc with the appropriate content. I then do this over and over for the various needs of the system.
All of that seems to work fine. However I am now in a bind where the options provided to navigate to each page have grown. For instance I have forward / backward buttons (like you woudl expect in a set-up wizard), as well as action menus at the top to jump to a page. So now the code is becoming very repetitious. If you select the next button, I write the current values to array, then repopulate. If you jump to the page from anywhere, I look to see where I am, write it to array, and populate the boxes. Thus if I need to change anything I have to make the change in numerous places in the code.
I know that this is not optimal. What I woudl like to do is run a continuous loop as I woudl normally do with Micros in C. So the program can look at a variable in each pass and if it is then it does. I am not however skilled enough to figure this loop out in QT. So my new thought was...
Is it possible to trigger an action or slot with a variable. For example, if the user presses the Next button it triggers a slot for a button that does not exist, so that QT will execute a particular line of Code? Then I can have 1 dedicated section focused on reading and writing boxes, with a bunch of actions that will take me there.
You can make a signal that is triggered with an emit call in your code, so you'd hook up the next button signal of clicked to a slot that does some work and moves on, or directly calls another signal that you've created that triggers a slot elsewhere, or do some work in a lambda triggered by the button press.
I would first load all the ComboBoxes options in a QStringList array (or maybe an array of QList<QLatin1String> lists - for memory saving and code efficiency).
Then I would keep an array of a 1000 integers for current ComboBox indexes.
When the user changes a value in some ComboBox, the currentIndexChanged signal will trigger the corresponding slot (a single slot for all the ComboBoxes would be enough - sender()->objectName() to get the name of the ComboBox which had sent the signal):
void WindowWidget::on_ComboBox_currentIndexChanged(int index)
{
name = sender()->objectName();
/* here change the corresponding integer in the current
indexes array */
}
On Next/Back button push repopulate the ComboBoxes. Also, provide some 'Save' button for saving the ComboBoxes indexes (or trigger the Save slot on some action, i.e. on window close either even on a timer signal).
I am subclassing QDoubleSpinBox to add some features (like incrementing the value based on the location of the cursor in the lineedit) and to change some features I find annoying. One of the latter is that intermediate values are emitted: e.g. if you want to enter the value 323 it will emit 3 then 32 then finally 323. I'd like to set it to only emit on entry (i.e. only actually change value on entry).
Anyway, I can't figure out how to capture these intermediate edits. I overrode setValue to see if I could stop it there somehow, but it apparently isn't called (or at least my override isn't). I'm not sure how the value is actually getting set while editing in line edit.
More generally, the logic of this box escapes me. Is there some documentation that explains e.g. "if you type a digit into the lineedit then this series of routines is called... while if you hit the up arrow, this series of routines is called?"
In case it matters, I'm using PyQt5
EDIT: Here is another case in which having access to this is important. Say I want to implement an undo/redo structure for the box. The only way I can think of to get access to the changed values is to connect to the valueChanged signal. But if I'm subclassing the box it seems a little convoluted to listen for a signal rather than just watch the value change 'internally' Or am I missing something here?
You could use the following signal:
void QAbstractSpinBox::editingFinished() [signal]
This signal is emitted editing is finished. This happens when the spinbox loses focus and when enter is pressed.
based on the documentation of QAbstractSpinBox:
http://qt-project.org/doc/qt-5.1/qtwidgets/qabstractspinbox.html#editingFinished
There is nothing that combines the arrow based changes and the editingFinished changes.
My use case was to let the user enter the value without getting the signal on each new digit, while still making ↑, ↓, Page Up, Page Down keys and arrow buttons work as usual, emitting the signal on each activation.
QAbstractSpinBox::editingFinished signal doesn't provide this functionality: it's only ever emitted when focus is lost or Return/Enter is pressed.
What does work exactly as I need is the keyboardTracking property of QAbstractSpinBox. If it's true (the default), the spinbox emits valueChanged on each digit typed. If you set it to false, it behaves exactly as I described in the beginning of this answer.
How can I refresh view after a certain event?
I have a view which contains multiple groups. I want to show or hide some groups.
onCreationComplete() or initialize() method works only at the beginning of the view creation.
Try invalidateDisplayList() on the view
Let me know if that doesn't do the trick and we'll try some other tricks.
I personally don't like the answer that says to call invalidateDisplayList (sorry no offense Nate nothing personal). I feel it's too vague and doesn't explain what this does under the hood and furthermore you shouldn't have to call it directly in cases such as the one explained in the OPs question. You can simply create booleans that are bindable for each of the groups you'd like to show/hide then in the event handler set those booleans to the appropriate value and if they are bound to the visible and include in layout properties of the containers those containers will internally call invalidateDisplayList after calling set visible and consequently commitProperties.
This is basically what happens under the hood as I understand it: The way this works is values aren't committed or used to update the display until the next frame this way it doesn't get bogged down doing unnecessary layout calculations. So you update the bindable property which fires an event which triggers a notification in the listener (in this case a function that sets the property on your control), that in turn passes along the value to the control which sets an internal flag to update the property and calls invalidateProperties. When it hits the next frame redraw it sees that the properties flag is dirty (true) and then calls commitProperties, this computes/sets the appropriate values (possibly also invalidating then "fixing" the size using invalidateSize() and measure()) and calls invalidateDisplayList, then during the same frame it sees that the display list flag is dirty so it calls updateDisplayList, here it uses the values of the properties to draw appropriately.
You should also be able to achieve this using states, which add or remove children from the display list based on an array of "actions" for each state.
I am using PyQt4, but this is general enough that it could just apply to QT.
I have a series of QComboBoxes that I fill from left to right (i.e. selecting an item in the leftmost will populate the next one. Selecting an item in that one will populate the next, and so on)
I am having difficulty getting my signals to fire under all situations (i.e. regardless of whether the current index changes or not AND regardless of whether the item is set by the user or set programatically).
More detail:
I rely on the signals of the first QCombox to fire whenever an item is selected so that I can populate the next QCombobox in the gui. I then rely on THAT QCombobox to emit a signal so that I can populate the next one. And so on.
I want to pre-select an item in each QCombobox based on the user's last interaction with the gui.
I have a unique function per QCombobox that is responsible for populating and pre-selecting just that QCombobox. The code looks something like this:
comboBox1.blockSignals(True)
comboBox1.clear()
comboBox1.addItems(sorted(itemList))
comboBox1.blockSignals(False)
comboBox1.setCurrentIndex(intLastSavedState1)
where intLastSavedState1 is an integer that is derived from the text that was last selected by the user the last time they had used the app. I had hoped that the last line of this function would fire a signal that would cause the next combo box's function to load and pre-select an item (comboBox2). And that action would then cause the next comboBox's function to activate and it would cascade to the next and the next. But it is not working across all cases.
I have tried two versions of the signals:
self.connect(comboBox1, QtCore.SIGNAL("currentIndexChanged(const QString&)"), self.load_comboBox2)
and
self.connect(comboBox1, QtCore.SIGNAL("activated(const QString&)"), self.load_comboBox2)
In the first case, the signal will fire only if the intLastSavedState1 is different than whatever is currently selected in the combo box. This causes an issue if the user had last selected item 0 from that list. In this case QT does not recognize my script setting the the current index to 0 as being a change (since after loading the box it appears to think it is already on index 0), and so the signal does not fire.
In the second case, the signal will fire regardless of what is currently selected in the combo box... but only if activated by the user. It will not fire when my script tries to set the current index programatically.
These appear to be my only two options regarding the signals. So... is there another way of pre-selecting items in a QCombobox that will trigger a signal each and every time?
Well... sometimes just the act of asking a question can lead you to a (partial) answer.
I have a work-around but I am still interested in hearing if someone has a better idea.
I am now programatically setting the index of the QCombobox to -1 immediately after loading it up. Then, when I programatically set the actual index based on the user's history, it will always be considered a change (i.e. it will never be -1) and the signal will fire
using: currentIndexChanged(const QString&)
So my code looks like this now:
comboBox1.blockSignals(True)
comboBox1.clear()
comboBox1.addItems(sorted(itemList))
comboBox1.setCurrentIndex(-1)
comboBox1.blockSignals(False)
comboBox1.setCurrentIndex(intLastSavedState1)
and my signal looks like this:
self.connect(comboBox1, QtCore.SIGNAL("currentIndexChanged(const QString&)"), self.load_comboBox2)
This functions... does anyone have a better idea?
Thanks agian.
You can check current Index of your ComboBox and then either call your slot or do call setCurrentIndex().
Example:
if comboBox1.currentIndex() == index:
self.load_comboBox2(index)
else
comboBox1.setCurrentIndex(index)
This way you will not end up calling slot twice.