Set Qt default encoding to UTF-8 - qt

In my Qt application my source code files are encoded as UTF-8. For the following code...
QMessageBox::critical(this, "Nepoznata pogreška", "Dogodila se nepoznata pogreška! Želite li zatvoriti ovaj program ?", QMessageBox::Yes, QMessageBox::No);
...when I show that message box, the character "š" wouldn't be displayed as "š", but as something strange. This is because Qt converts all C-strings as if they are encoded using LATIN-1. To solve this I've been using:
QMessageBox::critical(this, QString::fromUtf8("Nepoznata pogreška"), QString::fromUtf8("Dogodila se nepoznata pogreška! Želite li zatvoriti ovaj program ?"), QMessageBox::Yes, QMessageBox::No);
Is there a way to get rid of all the calls to QString::fromUtf8()?

Have you tried using QTextCodec::setCodecForCStrings(QTextCodec::codecForName("UTF-8"))?

setCodecForCStrings() had been deprecated.
Try instead,
QTextCodec::setCodecForLocale(QTextCodec::codecForName("UTF-8"));
It worked for me.

Regarding the "guess" that "Qt5 assumes all source files are UTF-8 encoded": Thiago Macieira explains the decision made by Qt's developers here.
The assumption can be disabled with QT_NO_CAST_FROM_ASCII according to the documentation.

Related

How can I get "canonical" name of the text encoding of current Atom active editor?

I have recently adding a fix for atom-script package to resolve garbled text output in compile&run Java code in non-English Windows environment. (Issue #1166, PR #2471)
After this, now in release script package 3.32.1, javac has options -J-Dfile.encoding=UTF-8 and -encoding UTF-8 both. (diff is here) I have just realized that it is better to provide actual encoding of the current active editor which holds the target source code for -encoding option. After some research, I have learnt that the encoding can be acquired by
atom.workspace.getActiveTextEditor().getEncoding()
but, after I have tested in Japanese edition Windows, it returns shiftjis and this is not valid encoding name for javac command line option. (It should be MS932, SJIS or something similar.) I have no idea where I can get this type of encoding names without writing large conversion table for all possible encoding names. Is there any good utility for such purpose?
EDIT:
For demonstrating what I have supposed to do, I have created branch on my fork. Diff is here.
Getting current source code editor encoding by
const fileEncoding = getJavaTextEncodingName(atom.workspace.getActiveTextEditor().getEncoding())
and pass it to javac via
const cmd = `javac -encoding ${fileEncoding} -J-Dfile.encoding=UTF-8 -Xlint -sourcepath '${sourcePath}' -d '${tempFolder}' '${filepath}' && java -Dfile.encoding=UTF-8 -cp '${tempFolder}' ${classPackages}${className}`
And, function "getJavaTextEncodingName()" is the core of the question.
function getJavaTextEncodingName(atomTextEncodingName) {
switch (atomTextEncodingName) {
case "shiftjis" :
return "MS932"
}
return "UTF-8"
}
It is obvious that this is converting "shiftjis" to "MS932" but, it is not so beautiful if we implement all possible encoding name conversions here, so I am seeking better alternative.

Why these strings are not translated by Qt 5

I'm porting a Qt4 project to Qt5 (Qt 5.4.1 + VS2013), the project have some string translations. The source file is UTF-8 encoded. But today I found the piece of code won't work (They all worked well in Qt4).
this->paraList.push_back( QPair<QString,QString>( QString(tr("℃:")), QString(tr("Ω")) ) );
'paraList' is a QList, and the strings in it finally shown in a QTableWidget. They both show correctly in QLiguist, but when my application run, the centigrade symbol and the Ohm symbol don't be translated correctly, as below
But all other strings are translated correctly. My locale is zh_CN. Why these two characters are so special?
Problem is encoding. You are using non ASCII characters as translation pattern. There was some change in Qt5 how c-strings are converted (I don't remember details) and I'm suspecting this might be a problem.
Try use trUtf8 this should fix the problem.

unicode character cannot be converted to cp1252

I am writing a QT5 application (with QT Creator) which uses special characters like zodiac signs. This code works perfectly fine on Linux Mint 14:
QString s = QString::fromUtf8("\u2648");
But when I compile it on Windows XP SP3 get a compiler warning which says that the current codepage is cp1252 and the character \u2648 cannot be converted. When I run the program this character is displayed as a question mark.
According to my system settings UTF8(codepage 65001) is installed on my Windows.
(Note, I have not tried this, and I don't know which compiler you are using, and am completely unfamiliar with QT, so I could be wrong. The following is based on general knowledge about Unicode on Windows.)
On Windows, 8-bit strings are generally assumed to be in the current codepage of the system (also called the "ANSI" codepage). This is never UTF-8. On your system, it's apparently cp1252. So there are actually two things going wrong:
You are specifying a Unicode character, which the compiler tries to covert to the correct codepage. On Windows, this results in a compile time error, because cp1252 doesn't have a code point to represent u+2648.
But assuming that the code would compile, it would still not work. You pass this string, which would be in in cp1251 to fromUtf8, which wants a UTF-8 string. As the string is not valid UTF-8, this would likely result in a runtime error.
On your Linux system, both works "by accident", because it uses UTF-8 for 8-bit strings.
To get this right, specify the 8-bit string in UTF-8 right away:
QString s = QString::fromUtf8("\xE2\x99\x88");
Here is my advice to get everithing work fine:
There is only one encoding type UTF-8! Use it everywhere if possible. So, in QtCreator settings set default codepage for sources UTF-8.
You can convert your source code in QtCreator: edit -> choose encoding and there reload in codepage. If it can't be done, use linux console application iconv this way:
iconv -f cp1252 -t utf-8 your_source_in_cp1251.cpp > your_source_in_utf8.cpp
I use this code snippet for C-strings in my source codes: in main.cpp add #include <QTextCodec>, and then do:
// For correct encoding
QTextCodec *codec = QTextCodec::codecForName("UTF-8");
QTextCodec::setCodecForCStrings(codec);

Unicode errors after upgrade to 2.1.0 final

I've recently upgraded a DjangoCMS project from 2.1.0beta3 to 2.1.0
final, and I've started getting Unicode errors during page editing.
There was a large volume of production content that was migrated
forward with South. I get the error while (using TinyMCE) I try to
insert another plugin, such as an image, into a text plugin or when I
try to add a plugin to a placeholder.
URL:
/admin/cms/page/188/edit-plugin/673/edit-plugin/676/
Stack Trace:
File "/srv/wsphp/wspython/virtualenv/iaffe-prod/lib/python2.6/site-packages/django/template/__init__.py", line 849, in render
return _render_value_in_context(output, context)
File "/srv/wsphp/wspython/virtualenv/iaffe-prod/lib/python2.6/site-packages/django/template/__init__.py", line 829, in _render_value_in_context
value = force_unicode(value)
File "/srv/wsphp/wspython/virtualenv/iaffe-prod/lib/python2.6/site-packages/django/utils/encoding.py", line 88, in force_unicode
raise DjangoUnicodeDecodeError(s, *e.args)
DjangoUnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 12: ordinal not in range(128). You passed in <django.forms.forms.BoundField object at 0xb73cedec> (<class 'django.forms.forms.BoundField'>)
If I repeatedly try to create the plugin, the ID (676 here) increments,
so it looks like the error happens when the form is rendered. This
affects link, picture, and teaser plugins, but not text, file or
snippet plugins.
I'd appreciate any help in isolating the cause here.
Thanks,
Michael
Bit of a late answer, but I had some problems with unicode and solved in with defining source code encodings also see http://evanjones.ca/python-utf8.html
I put
# -*- coding: utf-8 -*-
at the top of the offending files and everything was sorted.
It turns out that this was a data migration issue. The ultimate solution was to force utf8 encoding in the relevant mysql tables using commands like:
alter table cms_page convert to character set utf8;

Qt moc error 1 - what does it mean?

I'm trying to build a project on Mac OSX, and it's giving me a cryptic error:
[moc_droparea.cpp] Error 1
droparea.cpp is (obviously) a file in the project. I checked that it exists in the project directory and is not corrupted. The file moc_droparea.cpp doesn't show up in the build folder after this error, so I'm assuming it's failing to build for whatever reason, but the error is too vague to help me figure out what's going on. Could anyone help me figure out what this means please?
Click on "compile output", scroll up and click the red line.
In my case the Red line was saying: You cant define an integer value in private slots..
Under the qt creator window, in "progress details" section, there is a button named "compile output" (button number 4). Errors are explained there with red font. Click it and scroll up.
The solution was annoyingly simple. I had a folder structure that put spaces (illegal characters) in the file path. I put underscores instead of spaces and it built fine. I would think the moc pre-processor could handle spaces in file names, but apparently not. I feel foolish, but at least the problem is solved now.
Hopefully this solution can help someone else.
This can be because of few other things as others have mentioned. I would like to add another one which is missing here.
You will get a "moc error 1" in case you create a class and add Q_OBJECT to it but do not inherit from QObject.
If you take a look at Compile Output there is a line saying:
Error: Class contains Q_OBJECT macro but does not inherit from QObject
Hence, the general approach to fix this problem is just taking a look at "Compile Output" window.
This can be because of many things I guess - I had a similar situation where I forgot to remove an entry in the .qrc file that didn't exist anymore.
So check your resource paths as well.
You can right click on the error 1 and select 'View output'. In my case, I had a bad file name in my qrc file.
Like J.Javan already pointed to, it might be helpful to check also the compiler output. In my case I found:
../stateMaschine/usermenu.h:57: Error: Class declarations lacks
Q_OBJECT macro. make: *** [Makefile:215: moc_usermenu.cpp] Error 1
So this helped me to fix the error by correction of the class declaration when using signals and slots:
class Menu : public QObject{
Q_OBJECT
...
Same Error 1 occured to me due to a ressource file (.qrc) which referred to a file name beginning with a period. When I removed the period from the file name, compilation worked again. Interestingly, the error only occured under Mac OSX using the Clang compiler. On Windows using the gcc compiler, the file name did not provoke an error.
Maybe the "[source file name] Error 1" message in general means that a file could not be found due to unexpected characters in the file path.
In my case, I ran out of space on SD card causing this sort of error.

Resources