Application slower on qt 4.8.0 than 4.7.4 - qt

I have an application that I was developing with Qt 4.7.4 but I had the problem (the bug is reported) with the button's (too small) hit area. So I change for Qt 4.8.0. Now my problem with the button is resolved, but my application runs really slower that it ran with Qt 4.7.4. Is there anything I need to do? Kind of settings...
Thanks

Related

QT5 webkit plugin issue

I have application created using QT 5.0.2. When launch the video window, blank screen is observed. I am using win8 64-bit OS(also VLC). There is no issue with QT4 in win7 32-bit. Video streaming is perfect. Using qt webit/webpage classes
Is there any way to check: whether plug-in(mainly to view the video frames) is enabled or not in qt web-kit browser ?
Qt 4.8 and latest version 5.0.2 doesn't support video.. here is the link
[http://qt-project.org/forums/viewthread/23636][1]
You can resolve the issue by using this blog. Sorry I did not tried this. may help you. You need to build qt twice and few more corrections!
[http://blog.enthought.com/open-source/fun-with-qtwebkit-html5-video/][2]
Some one already mentioned the qt open bug against it.
[https://bugreports.qt-project.org/browse/QTBUG-22883][3]

Qt Creator crashes loading Examples

There is an Example tab at the Qt Creator(2.6.1)'s Welcome page, which is supposed to show the already made Qt Project Examples. But whenever I click on that, Qt creator closes automatically. Sometimes it shows the Example projects for 1 or 2 seconds and the exits. Any idea?
You probably need to configure Qt Creator to find your Qt installation.
Compiler configuration for Qt Creator
And you might need to get the msvs compiler, too.
http://www.microsoft.com/visualstudio/eng/products/visual-studio-express-products
They now have the mingw version available for windows with Qt 5.0.2.
http://qt-project.org/downloads
Also if you installed Qt without the examples that may also cause this error.
Hope that helps.

Debugging a version of Qt Creator and plugins all built from source

My goal is to be working on / debugging qt creator plugins and, maybe, editing / debugging qt creator source code. Towards this end I've tried a couple of things:
Downloading source for the qt sdk and qt creator, compiling each, and then making a qt creator plugin project and hooking everything together by hand. This got complicated pretty quickly (I tried to keep my plugin project outside the qt-creator/src/plugin/ folder) and doesn't really get me to a nice spot in terms of debugging.
Using an installed version of the qt creator to open the qtcreator.pro that came along with the source, adding a qt creator plugin as a sub project, and building everything from the already installed version of qt creator.
I like the second approach a lot because I have control over everything but I can rely on qt creators tools that make projects, enhance debugging, etc. There's just one small problem...
When I run my shiny new build of qt creator (with my plugin project) from inside the installed version all I get is a popup called "qtcreator_process_stub" that says "This is an internal helper of Qt Creator. Do not run it manually. Press to close this window..."
So I'm not really sure how to debug my build of qt creator from my instance of qt creator. Any ideas? Note: if I run the generated Qt Creator.app I get a functioning instance of qt creator with my plugin loaded properly.
I believe this was a versioning problem. I had an older version of the ide installed and was using it to build and debug a newer version of the ide.
I was able, in the older ide, to launch and debug the new ide as an external process through the debug menu... but that was mildly annoying.
Once I installed a new version of the ide I was able to debug like normal.

Dragging widgets to window won't work

I'm using Qt Creator for several months now and from time to time, I get a problem dragging widgets like buttons, line edits and so from the toolbox to the window.
I try by removing the layouts but still get the same issue.
I use Qt Creator 2.4.0 on OS X 10.7.2
Thanks for helping
I fixed this problem by upgrading Qt Creator to version 2.4.1 on OS X
The solution described above by #spyke might also be helpful for Windows users.
It case there is a dead link, the solution for Windows says :
I was using Qt Designer for Qt Jambi built with Qt 4.6.4 on Windows 7 ×64 when this problem occurred. After a while I realized that the problem was not only in Qt designer, but in Windows in general: Explorer, FileZilla and more.
The solution was then found by searching for general Windows 7 drag and drop problems [answers.microsoft.com].
In short: Select a file in Windows Explorer with click and hold left mouse button. While holding the button down, hit the Esc key. Then drag and drop starts working again.

Is Qt Creator built with Qt Creator?

Questions:
Is Qt Creator built with Qt Creator?
Similarly, is Qt Designer built with Qt Designer?
BTW, why are there two Qt IDEs? Are they competitors? Which one should I use? I am using Creator.
What is Qt SDK? I am asking this because the Qt Designer & Creator 2.2.1 and Qtmake 4.7.4 that I installed thro ubuntu 11.10 s/w centre does not work. The build menu is all greyed out.
When I downloaded the latest QtSDK (2.3.1/4.7.4) into a separate installation into /opt/QtSDK, both the ubuntu sanctioned installation and the /opt/QtSDK would work as expected.
Why did my ubuntu sanctioned installation not work without the SDK? What does the SDK do?
This one is for Ubuntu enthusiasts - Qt IDE requires the SDK to work, and yet ubuntu released both Creator/Designer without checking if they work first? There is no QtSDK installation item in s/w centre. Is that intentional, or a procedural bug?
After I build my desktop app (I am building a tabbed file explorer) on Linux, what steps do I need to make to have it running on Windows 7/Vista? Will I rebuild on a windows version of Qt Creator?
I also notice that Qt Creator code generation is not perfect. It would forget to include some Qt library files in the auto-generated code, and I had to correct that manually.
Is Qt Creator built with Qt Creator?
I believe so.
That doesn't mean that everyone who works on Qt has to use it - just that I believe that lots of people do.
I don't work for any of the companies that have produced Qt, but my reasoning is:
A Google search for "dogfooding qt creator" brings up plenty of hits, including this comment from November 2010:
We’re also “dogfooding” by releasing complex apps like Qt Creator and the Ovi Suite on the desktop ports of Qt
They've put a massive amount of effort into Qt Creator over the last few years. It's hard to imagine that being worthwhile, unless they used it themselves
At recent Qt Developer Days, Qt Developers have spoken really enthusiastically about Qt Creator
Similarly, is Qt Designer built with Qt Designer?
Yes. A look at the Qt Designer source code shows plenty of .ui (Designer) files.
Why are there two Qt IDEs? Are they competitors? Which one should I use? I am using Creator.
When you edit .ui files insiide Qt Creator, you are still running Qt Designer: it's simply showing the Designer window inside Creator, for convenience.
What is Qt SDK? ... What does the SDK do?
Qt SDK is just a convenient way to download all the Qt tools in one go. You don't have to use it.
This one is for Ubuntu enthusiasts ... Is that intentional, or a procedural bug?
Sorry - no idea. It's hard to imagine it being intentional though.
After I build my desktop app (I am building a tabbed file explorer) on Linux, what steps do I need to make to have it running on Windows 7/Vista? Will I rebuild on a windows version of Qt Creator?
You will need to install Qt on a Windows PC, and then build your source code in it.
You can either do that by using Qt Creator and the Windows compiler it includes (mingw) or you can use another compiler, if you have one, e.g. Visual Studio.
I also notice that Qt Creator code generation is not perfect. It would forget to include some Qt library files in the auto-generated code, and I had to correct that manually.
If you've used any non-Qt classes in arguments to signals and slots, then this answer may help you there.

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