記事本應用程序中的段錯誤

好的。我知道我發佈的代碼太多，但錯誤是程序員的噩夢。（分段錯誤）這是我的第一個應用程序，並得到了Qt創建者教程的幫助。請幫忙。記事本應用程序中的段錯誤

的notepad.h文件：

#ifndef NOTEPAD_H 
#define NOTEPAD_H 

#include <QMainWindow> 
#include <QPlainTextEdit> 


class Notepad : public QMainWindow 
{ 
    Q_OBJECT 

public: 
    Notepad(); 

protected: 
    void closeEvent(QCloseEvent *closeEvent); 

private slots: 
    void open(); 
    bool save(); 
    bool saveAs(); 
    void newFile(); 
    void documentWasModified(); 

private: 
    QPlainTextEdit *textField; 
    QString curFile; 

    QMenu *fileMenu; 
    QMenu *editMenu; 
    QMenu *helpMenu; 

    QToolBar *fileToolBar; 
    QToolBar *editToolBar; 

    QAction *newAct; 
    QAction *loadAct; 
    QAction *saveAct; 
    QAction *saveAsAct; 
    QAction *copyAct; 
    QAction *pasteAct; 
    QAction *cutAct; 
    QAction *exitAct; 

    void createMenu(); 
    void showStatusBar(); 
    bool maybeSave(); 
    bool saveFile(const QString &fileName); 
    void loadFile(const QString &fileName); 
    void setCurrentFile(const QString &fileName); 
    void createActions(); 
    void createToolBars(); 
    QString strippedName(const QString &fullFileName); 

}; 

#endif

的notepad.cpp文件：

#include <QtGui> 
#include <QMainWindow> 
#include "notepad.h" 

Notepad::Notepad() 
{ 
    textField = new QPlainTextEdit; 
    setCentralWidget(textField); 
    setWindowTitle(tr("The building of a notepad....")); 
    createActions(); 
    createMenu(); 
    createToolBars(); 
    showStatusBar(); 

    connect(textField->document(),SIGNAL(contentsChanged()),this,SLOT(documentWasModified())); 
    setCurrentFile(""); 
    setUnifiedTitleAndToolBarOnMac(true); 
} 

void Notepad::createActions() 
{ 
    newAct = new QAction(QIcon(":/images/new_File.png"),tr("&New"),this); 
    newAct->setShortcuts(QKeySequence::New); 
    newAct->setStatusTip("Create A new File!"); 
    connect(newAct,SIGNAL(triggered()),this,SLOT(newFile())); 

    loadAct = new QAction(QIcon(":/images/open_File.gif"),tr("&Load"),this); 
    loadAct->setShortcuts(QKeySequence::Open); 
    loadAct->setStatusTip("Open an existing file!"); 
    connect(loadAct,SIGNAL(triggered()),this,SLOT(open())); 

    saveAct = new QAction(QIcon(":/images/save_File.png"),tr("&Save"),this); 
    saveAct->setShortcuts(QKeySequence::Save); 
    saveAct->setStatusTip("Save the file!"); 
    connect(saveAct,SIGNAL(triggered()),this,SLOT(save())); 

    copyAct = new QAction(QIcon(":/images/copy.png"),tr("&Copy"),this); 
    saveAsAct->setShortcuts(QKeySequence::Copy); 
    saveAsAct->setStatusTip("Copy!"); 
    connect(saveAsAct,SIGNAL(triggered()),this,SLOT(copy())); 

    saveAsAct = new QAction(QIcon(":/images/save_As.png"),tr("&Save As"),this); 
    saveAsAct->setShortcuts(QKeySequence::SaveAs); 
    saveAsAct->setStatusTip("Save As!"); 
    connect(saveAsAct,SIGNAL(triggered()),this,SLOT(saveAs())); 

    exitAct = new QAction(QIcon(":/images/exit.png"),tr("&Exit"),this); 
    exitAct->setShortcuts(QKeySequence::Close); 
    exitAct->setStatusTip("Exit!"); 
    connect(exitAct,SIGNAL(triggered()),this,SLOT(close())); 

    pasteAct = new QAction(QIcon(":/images/paste.gif"),tr("&Paste"),this); 
    pasteAct->setShortcuts(QKeySequence::Paste); 
    pasteAct->setStatusTip("Paste Text!"); 
    connect(pasteAct,SIGNAL(triggered()),textField,SLOT(paste())); 

    cutAct = new QAction(QIcon(":/images/cut.png"),tr("&Cut"),this); 
    cutAct->setShortcuts(QKeySequence::Cut); 
    cutAct->setStatusTip("Cut Text!"); 
    connect(cutAct,SIGNAL(triggered()),textField,SLOT(cut())); 

    copyAct = new QAction(QIcon(":/images/copy.copy"),tr("&Copy"),this); 
    copyAct->setShortcuts(QKeySequence::Copy); 
    copyAct->setStatusTip("copy Text!"); 
    connect(copyAct,SIGNAL(triggered()),textField,SLOT(copy()));  

    copyAct->setEnabled(false); 
    cutAct->setEnabled(false); 
    connect(textField,SIGNAL(copyAvailable(bool)),copyAct,SLOT(setEnabled(bool))); 
    connect(textField,SIGNAL(copyAvailable(bool)),cutAct,SLOT(setEnabled(bool))); 

} 

void Notepad::createMenu() 
{ 
    fileMenu = menuBar()->addMenu(tr("&File")); 
    fileMenu->addAction(newAct); 
    fileMenu->addAction(loadAct); 
    fileMenu->addAction(saveAct); 
    fileMenu->addAction(saveAsAct); 
    fileMenu->addAction(exitAct); 

    editMenu = menuBar()->addMenu(tr("&Edit")); 
    editMenu->addAction(cutAct); 
    editMenu->addAction(copyAct); 
    editMenu->addAction(pasteAct); 

    menuBar()->addSeparator(); 
    helpMenu = menuBar()->addMenu(tr("&Help")); 
} 

void Notepad::createToolBars() 
{ 
    fileToolBar = addToolBar(tr("File")); 
    fileToolBar->addAction(newAct); 
    fileToolBar->addAction(loadAct); 
    fileToolBar->addAction(saveAct); 
    fileToolBar->addAction(saveAsAct); 

    editToolBar = addToolBar(tr("Edit")); 
    editToolBar->addAction(cutAct); 
    editToolBar->addAction(copyAct); 
    editToolBar->addAction(pasteAct); 


} 

void Notepad::showStatusBar() 
{ 
    statusBar()->showMessage(tr("Ready!")); 
} 

void Notepad::closeEvent(QCloseEvent *event) 
{ 
    if(maybeSave()) 
     event->accept(); 
    else 
     event->ignore(); 
} 

void Notepad::documentWasModified() 
{ 
    setWindowModified(textField->document()->isModified()); 
} 

bool Notepad::saveAs() 
{ 
    QString fileName = QFileDialog::getSaveFileName(this); 
    if(fileName.isEmpty()) 
     return false; 
    return saveFile(fileName); 
} 

bool Notepad::save() 
{ 
    if(curFile.isEmpty()) 
     return saveAs(); 
    else 
     return saveFile(curFile); 
} 

void Notepad::open() 
{ 
    if(maybeSave()) 
    { 
     QString fileName = QFileDialog::getOpenFileName(this); 
     if(!fileName.isEmpty()) 
      loadFile(fileName); 
    } 

} 

void Notepad::newFile() 
{ 
    if(maybeSave()) 
     { 
      textField->clear(); 
      setCurrentFile(""); 
     } 

} 

bool Notepad::maybeSave() 
{ 
    if(textField->document()->isModified()) 
     { 
      QMessageBox::StandardButton ret; 
      ret = QMessageBox::warning(this, 
             tr("Warning!"), 
             tr("Do you want to save the changes?"), 
             QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel 
             ); 
      if(ret==QMessageBox::Cancel) 
       return false; 
      if(ret==QMessageBox::Save) 
       return save(); 
     } 
    return true; 
} 

bool Notepad::saveFile(const QString &fileName) 
{ 
    QFile file(fileName); 
    if(!file.open(QFile::WriteOnly | QFile::Text)) 
     { 
      QMessageBox::warning(this, 
           tr("Error!"), 
           tr("%1 file cannot be saved.\nError:").arg(fileName).arg(file.errorString()) 
           ); 
      return false; 
     } 
    QTextStream out(&file); 
    #ifndef QT_NO_CURSOR 
    QApplication::setOverrideCursor(Qt::WaitCursor); 
    #endif 

    out << textField->toPlainText(); 

    #ifndef QT_NO_CURSOR 
    QApplication::restoreOverrideCursor(); 
    #endif 

    setCurrentFile(fileName); 
    statusBar()->showMessage(tr("File Saved.:)"),3000); 
    return true; 
} 

void Notepad::loadFile(const QString &fileName) 
{ 
    QFile file(fileName); 
    if(!file.open(QFile::ReadOnly | QFile::Text)) 
     { 
      QMessageBox::warning(this, 
           tr("error"), 
           tr("error loading %1 file.\nError:%2").arg(fileName).arg(file.errorString()) 
           ); 
      return; 
     } 
    QTextStream in(&file); 

    #ifndef QT_NO_CURSOR 
    QApplication::setOverrideCursor(Qt::WaitCursor); 
    #endif 

    textField->setPlainText(in.readAll()); 

    #ifndef QT_NO_CURSOR 
    QApplication::restoreOverrideCursor(); 
    #endif 

    setCurrentFile(fileName); 
    statusBar()->showMessage(tr("File Loaded!"),3000); 
} 

void Notepad::setCurrentFile(const QString &fileName) 
{ 
    QString curFile = fileName; 
    textField->document()->setModified(false); 
    setWindowModified(false); 

    QString shownName = curFile; 
    if(curFile.isEmpty()) 
     shownName = "untitled.txt"; 

    setWindowFilePath(shownName); 
} 

QString Notepad::strippedName(const QString &fullFilename) 
{ 
    return QFileInfo(fullFilename).fileName(); 
}

的main.cpp中：

#include <QApplication> 
#include <QtGui> 
#include "notepad.h" 

    int main(int argc, char **argv) 
    { 
     //Q_INIT_RESOURCE(application); 

     QApplication app(argc, argv); 
     //app.setStyle("motif");       //possible styles: windows,plastique,cde,motif etc. 
     app.setOrganizationName("Trolltech"); 
     app.setApplicationName("Application Example"); 
     Notepad mainWin; 
    #if defined(Q_OS_SYMBIAN) 
     mainWin.showMaximized(); 
    #else 
     mainWin.show(); 
    #endif 

     return app.exec(); 
    }

來源

2012-10-04 sudeepdino008

您是否在調試器中運行代碼？發生了什麼？ – 2012-10-04 18:07:29

像gdb？它指出QKeySequence :: part存在一些問題（在createActions（）函數中） – sudeepdino008

在這種情況下，粘貼完整的backtrace（'bt'in gdb） –

調試器是你的朋友。學會使用它。

有一個複製粘貼錯誤：

copyAct = new QAction(QIcon(":/images/copy.png"),tr("&Copy"),this); 
saveAsAct->setShortcuts(QKeySequence::Copy); 
saveAsAct->setStatusTip("Copy!"); 
connect(saveAsAct,SIGNAL(triggered()),this,SLOT(copy()));

這應該是：

copyAct = new QAction(QIcon(":/images/copy.png"),tr("&Copy"),this); 
copyAct->setShortcuts(QKeySequence::Copy); 
copyAct->setStatusTip("Copy!"); 
connect(copyAct,SIGNAL(triggered()),this,SLOT(copy()));

您使用未定義的指針。這不是調試器無法處理的噩夢。

來源

2012-10-04 18:16:41

這是正確的。謝謝。順便說一句，圖像不加載。我是否需要在.qrc文件中進行一些更改？ – sudeepdino008

這不是一個「聊天」，不要在現有的問題中發佈其他問題 –

記事本應用程序中的段錯誤

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