Qt5 dynamic translation issues for C++ defined properties - qt

I am currently working on somebody else code and I need to fix a bug linked with dynamic translation.
When the language is changed, the Loader is reloaded, it works but it generates unwanted effects (including the bug mentioned above).
So I tried to look for a way to dynamically change the translation without reloading everything.
I added m_engine->retranslate() in my switchLanguage function and this works perfectly, but only for texts directly defined in QML files. The thing is there is also a lot of text defined with setContextProperty in the C++ main controller class, and for them, it doesn't work at all (which seems pretty normal since m_engine is a QQmlApplicationEngine).
I don't see how I can simply force these texts to retranslate too. I have them in pretty much every controller function and they are used by different QML files. I am afraid that there will be no other choice but to change completely the way translation is managed. I hope advanced programmers can help me with this.
Other information:
I work with 5.13.0 version of Qt.
I don't use Designer and cannot use ui.retranslateUi().

It's hard to tell how your main controller class looks like, so here is a short general answer.
You can install an eventFilter and listen for LanguageChange.
In constructor of "main controller class", add this:
auto *core = QCoreApplication::instance();
if(core != nullptr)
{
core->installEventFilter(this);
}
Then add a function to your class:
bool MainControllerClass::eventFilter(QObject *watched, QEvent *event)
{
Q_UNUSED(watched);
if(event->type() == QEvent::LanguageChange)
{
//set properties again or emit property changed signals
}
}

Related

Unable to override OnApplyTemplate

I'm trying to override the NavigationView behavior:
public partial class CustomizableNavigationView : NavigationView
{
public CustomizableNavigationView()
{
// This gets called
}
protected override void OnApplyTemplate()
{
// This doesn't
}
}
It works on UWP, but not on Android. On Android, it doesn't call OnApplyTemplate and the screen remains blank, there's not content. Questions:
Why doesn't OnApplyTemplate get called on Android? I see that here: https://platform.uno/docs/articles/implemented/windows-ui-xaml-frameworkelement.html it says OnApplyTemplate() is on all platforms
There's no error or anything displayed in the Output panne in VS while running with debugger. Should there be any in this case? Do I need to enable something to log errors?
I noticed that if I don't use partial it gaves me error saying partial is required. This is required only on Android, why is that? A more in-depth explanation would help a lot to understand how things work.
Once I figure out why OnApplyTemplate is not called, I want to do this:
base.OnApplyTemplate();
var settingsItem = (NavigationViewItem)GetTemplateChild("SettingsNavPaneItem");
settingsItem.Content = "Custom text";
My hunch is this won't work on Android. Am I correct? :)
Jerome's answer explains why OnApplyTemplate() was not getting called, to address your other questions:
You can configure logging filters for Uno, this is normally defined in App.xaml.cs. Warnings should be logged by default.
The partial is required because Uno does some code-gen behind the scenes to create plumbing methods used by the Xamarin runtime. Specifically because the control is ultimately inheriting from ViewGroup on Android, it's a native object, and requires special constructors that are used only by Xamarin's interop layer. There's some documentation in progress on this.
Try it and see. :) GetTemplateChild() is supported, and setting ContentControl.Content in this way is supported, so I would expect it to work.
At current version (1.45 and below), the application of styles is behaving differently from UWP. We're keeping track of this in this issue.
The gist of the issue is that Uno resolves the style using the current type and not DefaultStyleKey, and cannot find an implicit style for CustomizableNavigationView.
A workaround for this is to either create a named style from the default NavigationView style, or create an implicit style that uses CustomizableNavigationView as the TargetType instead of NavigationView.

OpenSceneGraph and Multiple Viewers

I'm using OpenSceneGraph and Qt to develop a simulation software. Simulations can involve multiple bots in the same virtual world. My requirements for views are as follows:
Ability to show static world cameras
Ability to show bot cameras
Ability to move these views around and/or stack them
To accomplish these tasks, I have made an 'OSGWidget' that uses an Osg Viewer to render the scene inside a QGLWidget. This OSGWidget is in turn put inside a QDockWidget that can be moved around and/or stacked, fulfilling that requirement.
The problem is that when using multiple singular viewers to render the same scene in different widgets, I get strange render behavior. Namely, textures do not display properly or sometimes even at all.
I have looked around SO and the OSG forums and while people have had similar problems, the only responses I have seen have suggested switching to an Osg CompositeViewer. For my purposes, I would like to avoid using that as it breaks my desired requirement of movable and stackable widgets rendering the same scene.
Is this an intractable situation that just isn't easily handled by Osg? I have seen several posts that say this is not how OSG is 'supposed to work' but they haven't really provided facts to support that claim. Has anyone done something similar or have any ideas/insight? I can provide code snippets if needed, but as this might just be a contradiction to Osg's ideology I will wait to get some responses.
Thanks to some help from the comments and from a couple other sites, I was able to successfully get the behavior I wanted from CompositeViewer.
Basically, all OSG Views go through my "WidgetDriver" which contains a CompositeViewer.
class OsgWidgetDriver {
public:
void init() {
compositeViewer = new osgViewer::CompositeViewer;
compositeViewer->setThreadingModel(osgViewer::Viewer::SingleThreaded);
compositeViewer->setReleaseContextAtEndOfFrameHint(false);
}
void start() {
initialized = true;
}
void stop() {
compositeViewer->stopThreading();
compositeViewer->setDone(true);
}
void updateFrame() {
if (initialized)
compositeViewer->frame();
}
void addView(osgViewer::View *view) { compositeViewer->addView(view); }
bool isInitialized() { return initialized; }
protected:
bool initialized;
osgViewer::CompositeViewer *compositeViewer;
};
Then, whenever I make a new Qt OSG Widget, I hand the osg::View off to the driver. I let the driver update the render window, while Qt can still update the QWidget accordingly. It even allows me to place the widget in a QDockWidget so I can move them around and stack them as needed.
Some final notes on the process if anyone else wants to do this:
You will very likely run into weird texture display problems when multiple OSG Viewers are looking at one scene. If that happens, use the osgUtil::Optimizer::TextureVisitor to set all textures to "UnrefImageAfterApply = false". This will allow proper texture displays across multiple osg::View instances.
The CompositeViewer options I set above, threading model to SingleThreaded and releaseContextAtEndOfFrame to false, are necessary if you want a single thread acting upon multiple views. If you use a widget driver like I did, you will want to do this.

How can I use Caliburn.Micro conventions to set a button's text and its action?

If I have a button in my View named, say, Save, then I can add a Save property to my ViewModel, and Caliburn.Micro will automatically bind it to my button's Content. For example:
public string Save { get { return StringResources.Save; } }
Or I can add a Save method to my ViewModel, and Caliburn.Micro will execute that method when the button is clicked. For example:
public void Save() {
Document.Save();
}
But what if I want to do both? C# doesn't let me declare a method and a property with the same name. Can I use conventions to both set the button's Content and the action to perform when it's clicked?
(I know I can manually bind one or the other, but I'd rather use conventions if it's practical.)
This is a common need, so you'd think it would be built into Caliburn.Micro, but it doesn't seem to be. I've seen some code that extends the conventions to support this (and I'll post it as an answer if nothing better comes along), but it's a workaround with some bizarre quirks -- so I'd like to hear if anyone else has made this work more cleanly.
Note: I did see this similar question, but it seems to be about whether this is a good idea or not; I'm asking about the mechanics. (I'll reserve judgment on whether it's a good idea until I've seen the mechanics. (grin))
Quick and dirty
<Button x:Name="Save"><TextBlock x:Name="SaveText"></TextBlock></Button>

How to know that widget is currently is running in Qt Designer

How can I in code of the custom Qt widget know that it is currently instantiated in Qt designer?
Use case:
I build a complex custom widget that has several child widgets like QPushButton, QLabel etc.
As application logic require, when widget is created most of those sub component are not visible but in design time when I put it on a form I would like to see them.
To be able to play with style sheet at design time.
Currently what I get is a empty is only a result of constructor - minimal view (actually empty in my case).
What I am looking for is to be able to do something like
MyQWidget::(QWidget *parent)
{
....
if(isRunningInDesigner())
{
myChildWidget1->setVisible(true);
myChildWidget2->setVisible(true);
myChildWidget3->setVisible(true);
}
else
{
myChildWidget1->setVisible(false);
myChildWidget2->setVisible(false);
myChildWidget3->setVisible(false);
}
....
}
So what should I put in to this bool isRunningInDesigner() ?
From the Qt Designer manual:
To give custom widgets special behavior in Qt Designer, provide an implementation of the initialize() function to configure the widget construction process for Qt Designer specific behavior. This function will be called for the first time before any calls to createWidget() and could perhaps set an internal flag that can be tested later when Qt Designer calls the plugin’s createWidget() function.
Those are methods from the QDesignerCustomWidgetInterface plugin interface. In short: you tell the widget to behave differently when Qt Designer asks your plugin to create instances of your custom widget.

Flex Truncating Button Labels

First and foremost, I apologize for any vagueness in this question. At this point, I'm simply trying to get some new ideas of things to try in order to diagnose this bug.
Anyway, the problem I'm having is with an application that's using a custom moduleloader. That moduleloader has been compiled into an swc and the moduleloader is being instantiated via its namespace. This all works perfectly fine. The problem I'm encountering is specific to mx:button controls used within modules. For whatever reason, their labels are being truncated so, for example, Sign In is showing up with an ellipsis, as Sign ...
After quite a bit of fooling around I have been able to establish the following:
This problem only seems to occur within modules. If a button control is used in the main mxml, the label does not get truncated.
The button control whose label is being truncated does not have a width specified (setting its width to 100% or a specific pixel width doesn't fix the issue)
The button control is using the default padding (messing with the padding by setting left and right to 5 or any other value doesn't help matters either).
We are not using any embedded fonts so I've ruled that out as a possibility as well.
mx:CheckBox and mx:LinkButton are equally impacted by this problem although mx:CheckBox also seems to not want to show its checkbox, it just shows the truncated label.
A potential side affect of this is that attaching a dataprovider to mx:ComboBox causes the combobox control to throw a drawing error but I'm not entirely certain that it's related to the above problem.
One interesting thing I did find while perusing the net for an answer was a mention of fontContext and its relationship to IFlexModuleFactory. There's no specification for fontContext within our implementation of moduleloader so I'm not entirely certain if this could be the issue. In any case, if anyone has any ideas, it would be hugely appreciated. On the other hand, if you know exactly what ails me and can provide me with an answer, I might just wet myself with excitement. It's late. I'm tired. I NEED my Flex app to play nice.
Thanks in advance,
--Anne
Edit: To clarify what I'm looking for with this question, I really just need to know the following:
Could this issue be caused by a namespace conflict?
What else can potentially override the default behavior of labels if no CSS has been implemented?
Has anyone encountered a problem with inheritance being lost while using a custom implementation of moduleloader?
Has anyone encountered this problem or a similar problem with or without using moduleloader?
I'm not sharing any code with this question simply because I'd have to share the entire application and, unfortunately, I can't do that. Again, I'm not looking for the end all, be all solution, just some suggestions of things to look out for if anyone has any ideas.
I've been dealing with this issue myself, off and on and in various forms, for a year, and while I haven't figured out just what's causing it yet, there's clearly a mismeasurement happening somewhere along the line.
What I have been able to to, though, is work around it, essentially by subclassing button-type controls (in my case, Button, LinkButton, PopUpButton, et. al.) and assigning their textField members instances of a UITextField extension whose truncateToFit element simply returns false in all cases:
public class NonTruncatingUITextField extends UITextField
{
public function NonTruncatingUITextField ()
{
super();
}
override public function truncateToFit(s:String = null):Boolean
{
return false;
}
}
The custom component just extends Button (or whatever other button-type control is the culprit -- I've created a half-dozen or so of these myself, one for each type of control), but uses a NonTruncatingTextField as its label, where specified by the component user:
public class NonTruncatingButton extends Button
{
private var _truncateLabel:Boolean;
public function NonTruncatingButton()
{
super();
this._truncateLabel = true;
}
override protected function createChildren():void
{
if (!textField)
{
if (!_truncateLabel)
textField = new NonTruncatingUITextField();
else
textField = new UITextField();
textField.styleName = this;
addChild(DisplayObject(textField));
}
super.createChildren();
}
[Inspectable]
public function get truncateLabel():Boolean
{
return this._truncateLabel;
}
public function set truncateLabel(value:Boolean):void
{
this._truncateLabel = value;
}
}
... so then finally, in your MXML code, you'd reference the custom component thusly (in this case, I'm telling the control never to truncate its labels):
<components:NonTruncatingButton id="btn" label="Click This" truncateLabel="false" />
I agree it feels like a workaround, that the component architecture ought to handle all this more gracefully, and that it's probably something we're both overlooking, but it works; hopefully it'll solve your problem as you search for a more definitive solution. (Although personally, I'm using it as-is, and I've moved on to other things -- time's better spent elsewhere!)
Good luck -- let me know how it works out.
I've used the custom button and link button class solutions and still ran into problems - but found a workaround that's worked every time for me.
Create a css style that includes the font you'd like to use for you label. Be sure to check 'embed this font' right under the text selection dropdown. Go back and apply the style to your button (or your custom button, depending on how long you've been bashing your hear against this particular wall), and voila!
Or should be voila...
I just came across this issue and solve it this way:
<mx:LinkButton label="Some label"
updateComplete="event.target.mx_internal::getTextField().text = event.target.label"
/>;
I've had some success preventing Flex's erroneous button-label truncation by setting labelPlacement to "bottom", as in:
theButton.labelPlacement = ButtonLabelPlacement.BOTTOM;
Setting the label placement doesn't seem to help prevent truncation in some wider button sizes, but for many cases it works for me.
In cases where you can't use a bottom-aligned button label (such as when your button has a horizontally aligned icon), janusz's approach also seems to work. here's a version of janusz's .text reassignment technique in ActionScript rather than MXML:
theButton.addEventListener(FlexEvent.UPDATE_COMPLETE, function (e:FlexEvent):void {
e.target.mx_internal::getTextField().text = e.target.label;
});
The preceding code requires you to import mx_internal and FlexEvent first, as follows:
import mx.events.FlexEvent;
import mx.core.mx_internal;
And here are the results…
Before (note truncation despite ample horizontal space):
After:
The only downside to this approach is you lose the ellipsis, but in my case I considered that a welcome feature.

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