langswitch.cpp

嵌入式LINUX下的自定义信号和槽、树型结构的内存管理、网格布局管理、动态改变语言的代码。

#include <QComboBox>
#include <QLabel>
#include <QVBoxLayout>
#include <QTranslator>
#include <QApplication>

#include "LangSwitch.h"

LangSwitch::LangSwitch() : QWidget()
{
    changeTr("en");    
    createScreen();
}

void LangSwitch::createScreen()
{
    combo = new QComboBox;
    combo->addItem("English", "en");
    combo->addItem("Chinese", "zh");
    combo->addItem("Latin", "la");
    
    label = new QLabel;
    refreshLabel();

    QVBoxLayout* layout = new QVBoxLayout;
    layout->addWidget(combo, 1);
    layout->addWidget(label, 5);

    setLayout(layout);
    
    connect(combo, SIGNAL(currentIndexChanged(int)), 
            this, SLOT(changeLang(int)));
}

void LangSwitch::changeLang(int index)
{
    QString langCode = combo->itemData(index).toString();
    changeTr(langCode);
    refreshLabel();
}

void LangSwitch::changeTr(const QString& langCode)
{
    static QTranslator* translator;

    if (translator != NULL)
    {
        qApp->removeTranslator(translator);
        delete translator;
        translator = NULL;
    }

    translator = new QTranslator;
    QString qmFilename = "lang_" + langCode;
    if (translator->load(qmFilename))
    {
        qApp->installTranslator(translator);
    }
}

void LangSwitch::refreshLabel()
{
    label->setText(tr("TXT_HELLO_WORLD", "Hello World"));
}