關(guān)鍵詞：QAction的信號、文件打開操作、文件保存操作、文件另存為操作

1. QAction的信號

• QAction被點(diǎn)擊之后會(huì)產(chǎn)生一個(gè)triggered信號
  通過信號與槽的機(jī)制能夠捕捉對QAction對象的操作，項(xiàng)目中可以將多個(gè)信號映射到同一個(gè)槽函數(shù)

connect(action, 
        SIGNAL(triggered()),
        this, 
        SLOT(slot_function()))

2. 文件打開操作

void MainWindow::onFileOpen()
{
    QString path = showFileDialog(QFileDialog::AcceptOpen, "Open");

    if( path != "")
    {
        QFile file(path);

        if( file.open(QIODevice::ReadOnly | QIODevice::Text))   //文件打開成功
        {
            mainEditor.setPlainText(QString(file.readAll()));

            file.close();

            m_filePath = path;

            setWindowTitle("NotePad - [" + m_filePath + "]");
        }
        else        // 文件打開失敗，彈出對話框提示
        {
            showErrorMessage(QString("Open file error! \n\n") + "\"" + path + "\"");
        }
    }
}

3. 文件保存操作

void MainWindow::onFileSave()
{
    if(m_filePath == "")
    {
        m_filePath = showFileDialog(QFileDialog::AcceptSave, "Save");
    }

    if( m_filePath != "")
    {
        QFile file(m_filePath);

        if( file.open(QIODevice::WriteOnly | QIODevice::Text) )
        {
            QTextStream out(&file);

            out << mainEditor.toPlainText();

            file.close();

            setWindowTitle("NotePad - [" + m_filePath + "]");
        }
        else
        {
            showErrorMessage(QString("Save file error! \n\n") + "\"" + m_filePath + "\"");

            m_filePath = "";
        }
    }
}

4. 文件另存為操作

 void MainWindow::onFileSaveAs()
 {
     QString path = showFileDialog(QFileDialog::AcceptSave, "Save As");

     if (path != "")
     {
         QFile file(path);

         if( file.open(QIODevice::WriteOnly | QIODevice::Text) )
         {
             QTextStream out(&file);

             out << mainEditor.toPlainText();

             file.close();

             m_filePath = path;

             setWindowTitle("NotePad - [" + m_filePath + "]");
         }
         else
         {
             showErrorMessage(QString("Save file error! \n\n") + "\"" + path + "\"");
         }
     }
 }

5. 小結(jié)

• Qt項(xiàng)目中盡量將界面代碼與功能代碼分離開
• Qt項(xiàng)目開發(fā)時(shí)盡量復(fù)用平臺(tái)中提供的相關(guān)組件
• Qt項(xiàng)目中的多數(shù)情況都是編寫相應(yīng)的槽函數(shù)
  槽函數(shù)用于相應(yīng)用戶操作
  槽函數(shù)是具體功能的觸發(fā)點(diǎn)

聲明：此文章僅是本人在學(xué)習(xí)狄泰QT實(shí)驗(yàn)分析課程所做的筆記，文章中包含狄泰軟件資料內(nèi)容，一切版權(quán)歸狄泰軟件所有！
實(shí)驗(yàn)環(huán)境：ubuntu10 + Qt Creator2.4.1 + Qt SDK 4.7.4