qt_国际化

关于qt的国际化，网上有相当的文章，这里要讲下要注意的一些地方。

1.qt的国际化可以分为动态加载和静态加载，动态加载会比静态加载复杂一些。

静态加载只要实现如下代码即可:

    QApplication app(argc, argv);
    QTranslator *translator = new QTranslator(&app);
    if (translator->load(":/translations/sys_Korean.qm"))
        app.installTranslator(translator);        

2.如果使用动态加载，加载语言文件成功后，需要手动调用刷新ui文本的函数。界面是designer画的话就方便一点，直接调用ui->retranslateUi(this);即可。界面要是手动画的话就麻烦一点，就需要自己实现retranslateUi函数。

3.界面中不是自己设置的text，需要加载qt自带的语言文件。但是自带的文件翻译较多，截取部分需要的翻译到自己实现qm文件中也可以实现。

4.Linguist语言家并不是必须的，在使用完lupdate后，可以进行手动修改ts文件，然后再使用lrelease生成qm文件。

类的声明：

class LangPage : public QWizardPage
{
    Q_OBJECT

public:
    LangPage(QWidget *parent = 0);
    ~LangPage();

private slots:
    void changeLang(int index);

private:
    void retranslateUi();
    void changeQtLang(QString langCode);
    QStringList findQmFiles();
    QString languageName(const QString &qmFile);

    QComboBox *comboBox;
    QHBoxLayout *layout;
};

类的实现：

static QTranslator *translator;

LangPage::LangPage(QWidget *parent)
    : QWizardPage(parent)
{
    setTitle(tr("Choose Language"));
    setSubTitle(tr("Specify where you want the wizard to put the generated "
                   "skeleton code."));
    setPixmap(QWizard::LogoPixmap, QPixmap(":/images/logo1.png"));

        comboBox = new QComboBox;
    layout = new QHBoxLayout;

    QStringList qmFiles = findQmFiles();
    for (int i = 0; i < qmFiles.size(); ++i) {
                comboBox->addItem(languageName(qmFiles[i]));
    }
        connect(comboBox, SIGNAL(currentIndexChanged(int)), this, SLOT(changeLang(int)));
    layout->addWidget(comboBox);
    setLayout(layout);
}

LangPage::~LangPage()
{
        delete comboBox;
        delete layout;
        if (translator != NULL)
        {
                qApp->removeTranslator(translator);
                delete translator;
                translator = NULL;
        }
}

void LangPage::changeLang(int index)
{
        QString langCode = comboBox->itemText(index);
        changeQtLang(langCode);
}

void LangPage::changeQtLang(QString langCode)
{
        if (translator != NULL)
        {
                qApp->removeTranslator(translator);
                delete translator;
                translator = NULL;
        }

        translator = new QTranslator;
        QString qmFilename = ":/translations/" + langCode + ".qm";
        if (translator->load(qmFilename))
                qApp->installTranslator(translator);
        retranslateUi();
}

void LangPage::retranslateUi()
{
        wizard()->restart();
        wizard()->setWindowTitle(tr("Setup Wizard"));

        setTitle(tr("Choose Language"));    
        setSubTitle(tr("Specify where you want the wizard to put the generated "
                   "skeleton code."));
}

QStringList LangPage::findQmFiles()
{
    QDir dir(":/translations");
    QStringList fileNames = dir.entryList(QStringList("*.qm"), QDir::Files,
                                          QDir::Name);
    QMutableStringListIterator i(fileNames);
    while (i.hasNext()) {
        i.next();
        i.setValue(dir.filePath(i.value()));
    }
    return fileNames;
}

QString LangPage::languageName(const QString &qmFile)
{
    QTranslator translator;
    translator.load(qmFile);
    return translator.translate("MainWindow", "English");
}

ts文件举例：

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE TS>
<TS version="2.0">
<context>
    <name>LangPage</name>
    <message>
        <source>Choose Language</source>
        <translation>Choose Language</translation>
    </message>
    <message>
        <source>Setup Wizard</source>
        <translation>Setup Wizard</translation>
    </message>
    <message>
        <source>Specify where you want the wizard to put the generated skeleton code.</source>
        <translation>Specify where you want the wizard to put the generated skeleton code.</translation>
    </message>
</context>
<context>
    <name>MainWindow</name>
    <message>
        <source>English</source>
        <translation>English</translation>
    </message>
</context>
<context>
    <name>QWizard</name>
    <message>
        <source>Go Back</source>
        <translation>Go Back</translation>
    </message>
    <message>
        <source>Continue</source>
        <translation>continue</translation>
    </message>
    <message>
        <source>Commit</source>
        <translation>Commit</translation>
    </message>
    <message>
        <source>Done</source>
        <translation>Done</translation>
    </message>
    <message>
        <source>Help</source>
        <translation>Help</translation>
    </message>
    <message>
        <source>&lt; &amp;Back</source>
        <translation>&lt; Back(&amp;B)</translation>
    </message>
    <message>
        <source>&amp;Finish</source>
        <translation>Finish(&amp;F)</translation>
    </message>
    <message>
        <source>Cancel</source>
        <translation>Cancel</translation>
    </message>
    <message>
        <source>&amp;Help</source>
        <translation>Help(&amp;H)</translation>
    </message>
    <message>
        <source>&amp;Next</source>
        <translation>Next(&amp;N)</translation>
    </message>
    <message>
        <source>&amp;Next &gt;</source>
        <translation>Next(&amp;N) &gt;</translation>
    </message>
</context>
<context>
    <name>SetupWizard</name>
    <message>
        <source>Setup Wizard</source>
        <translation>Setup Wizard</translation>
    </message>
</context>
</TS>