If the question is "How to change a button's color?" the answer is probably something like

myButton->setStyleSheet("background-color: red;");

If the question is how to "How to change the button's color WHEN some conditions" the answer could be

[Somewhere inside a method] if (conditionsMet) { Q_EMIT(ChangeButtonColor()); } [somewhere in constructor, most likely] connect(this, &MyClass::ChangeButtonColor, this, [m_button](){ m_button->setStyleSheet("background-color: red;"); });

This is one way to connect signal/slot to actually change the button's color when some conditions are met. But the condition can be in another class than the one owning the button, the signal can be emitted by another component and not inside a method, and the code that changes the color can be in a method instead of a lambda.

What might be useful would to copy/paste some code to help you more specifically.

EDIT:
@J.Hilk 's solution, tho a bit complicated for a beginner, is much more robust and pro. It depends on how serious your project is and if you have sufficient knowledge in Qt.

AFAIK, the BPI is very close to the Raspberry Pi, you should take a look at this wiki entry.

By the way, why are you trying to build an outdated version of Qt ? The current LTS is the 5.9 series with 5.12 around the corner.

@another_one You should start here: http://doc.qt.io/qt-5/multimediaoverview.html

@Linuxfluesterer No it's not the size of your hard drive, it's the size of the RAM allocated to that machine and how much it uses for /tmp.

So do a df -h and you can post the output or at least see how much space you have on tmp. If it is less than the 1.4gb needed for the install, up it. Or as I suggested temporarily point /tmp to a hard disk if you don't have the ram for a bigger /tmp.

@hassene
Hi and welcome
Is there a reason you simply dont use a layout ?
To make it autofollow the size of window ?
if you place a QLabel on a form ( mainwindow.ui) , right click somewhere on
empty form, and select Layout menu and select layout, the label will follow maniform.
https://doc.qt.io/qt-5.10/examples-layouts.html

@mrjj Thakn you.

Hi and welcome to devnet,

You have to give more information about your setup.

What device are you going to use ?
What version of Qt ?
What Linux distribution ?
What graphical backend ?

@SGaist Your comment was very helpful. I checked the contents by printing them and saw that when I called the process, the file was still being written (since I write a JSON file from the GUI). So I added one more line QFile.close() and now the python script is called only after JSON gets written from the GUI. Now it is running fine.

Hi,

Please give the complete error log.

@Alain38 OK: It seems in fact that wat just a problem with the console. By sending the text to the URL (using QUrlQuery for encoding) I have the text with the accents.

Dear Alain38,

Did you make it finally work? I got stocked with the exact same problem.

Hi
Just create a function and use that instead of new directly

QComboBox * MakeDefaultCB(QObject *Parent) { QComboBox * cur= new QComboBox (Parent); cur->addItem(QString("defect 1")); cur->addItem(QString("defect 2")); ... return cur; } dbox1.push_back(MakeDefaultCB(this));

@NewMoon
see QTBUG-38181
It's a known limitation of QJSEngine.
If you can, switch to QScriptEngine (QML).

Hi and welcome to devnet,

What's dxftoqet3db.h ?
Where does it come from ?
Does it use an external .dll ?

I actually switched to QtAV for video output, and so far it's been working flawlessly under standard QT App setup.

If I could ever get the QML/Quick setup to acknowledge it's been installed I'd test that end of things, but for now it's accomplishing exactly what I need.

Thanks again for the assistance!.

@Rondog Ah.. Sorry. I was careless. I read source and saw that

#ifndef Q_OS_WINRT #define QT_USE_REGISTRY_TIMEZONE 1 #endif

All be ok and work correct on Windows XP. Sorry guys

The binaries may scan fine but the behavior of the program could be the trigger. If the program does things that are suspicious it will get more attention (especially a new program).

Just to make sure I would build Qt from source or only use binaries from a trusted source with a checksum hash that you can verify.

This is a big concern I have when moving between Windows computers. I have not had problems but I always keep in the back of my mind that everything might be deleted in the blink of an eye and snowball into a bad day - bleh!

https://bugreports.qt.io/browse/QTBUG-57072

@pauledd
:)
class MyWidget : public QWidget << yes that is subclassing :)

Also, a widget can only paint on it self.
its not possible to paint on other widget from inside a
paintevent.
Thats why the first sample didnt work. You asked painter to paint on tab from inside mainwindows paintEvent :)
I guess you already found out but its just to make clear for other readers.

@Neosw
Thanks a lot!!
It seems there was some kind of bug in Qt5.6 which stopped the model from rendering.
I updated to Qt5.7 and it worked!
:)

In my case this function works:

onFeaturePermissionRequested: { console.log("onFeaturePermissionRequested"); webEngineView.grantFeaturePermission(securityOrigin, feature, true); }

Tested on Qt 5.6 and Qt 5.7 on Desktop and Embedded

@raven-worx Thank you, it's cleart to me now. One more question - is there any possibility of grabing image of webview on android excent taking screenshot and cropping it? I know this solution is not ideal, but can't rewrite whole app and its UI logic now.

Thank you for answer :)

Since your on Linux, why not install the taglib devel package from your distribution ?

Here is the catch

you have to use arm-linux-gnueabihf-'' instead of arm-linux-gnueabihf.

@SGaist thanks for your help

One thing to add to @kshegunov, terminating these applications ungracefully may have side effects on the stability of your system.

Problem Solved.

CODE

QModelIndex index2=proxymodel->mapToSource(index); //Returns the source model index (In my case it was QFileSystemModel) QString selectedrow=filemodel->fileInfo(index2).absoluteFilePath(); //filemodel is My QFileSystem Model.

Hi,

Apply the same filter you are using for your single folder version except that this time rather than using a QString you should keep a QStringList of the folders you want to show and use that.

That wasn't really clear from your original description.

In that case, use a filter. QSortFilterProxyModel for example

Hi @Wieland ,

I did not test the code. But Yes, you are right. I tested @Punit 's code after my comment. It worked for me too(missed only that semicolon).

Solved: the cause was the stub in mesa3d drm backend. It's solved by altering the backend.

Hi and welcome to devnet,

Looks like the keyboard layout of your Pi doesn't match the keyboard layout of your desktop computer.

Which are both ?

@raven-worx Thanx for the suggestion. I think we can go a long way with this, except that we are on Windows and it seems we need some Windows-specific MIME-conversions. We'll try to tinker a bit with that.