How to make a specific string read-only in a textedit in Qt?

[prab]

Hi,

I am designing a command prompt using Qt textedit with the prompt as shown below...

comman-prompt>

The string is coming every time an enter is pressed as shown below...

comman-prompt> ls (with enter pressed)
comman-prompt> ps (with enter pressed)
comman-prompt>

but I do not have any idea how to disable the back space from removing this prompt. I mean the prompt should always be read-only with the cursor and back space should not enter in to it.

Any suggestion is highly appreciated.

Thanks in Advance,
Prabhu

[Santosh Reddy]

This example should give you some idea. This example is based on Qt5, but should be trival to run using Qt4

#include <QtGui>
#include <QtCore>
#include <QtWidgets>
 
class TextEdit : public QTextEdit
{
    Q_OBJECT
public:
    explicit TextEdit(const QString & prompt, QWidget * parent = 0)
        : QTextEdit(parent)
        , mPrompt(prompt)
        , mCount(0)
    {
        append(mPrompt);
    }
 
protected:
    void keyPressEvent(QKeyEvent * event)
    {
        if((event->key() == Qt::Key_Up)   or
           (event->key() == Qt::Key_Down) or
           (event->key() == Qt::Key_Left) or
           (event->key() == Qt::Key_Right))
        {
            return;
 
        }
        else if(event->key() == Qt::Key_Return)
        {
            append(mPrompt);
            mCount = 0;
            return;
        }
        else if(event->key() == Qt::Key_Backspace)
        {
            if(mCount > 0)
                mCount--;
            else
                return;
        }
        else if((event->key() & Qt::Key_Escape) == Qt::Key_Escape)
        {
            return;
        }
        else
        {
            mCount++;
        }
 
        return QTextEdit::keyPressEvent(event);
    }
 
private:
    QString mPrompt;
    unsigned int mCount;
};
 
int main(int argc, char ** argv)
{
    QApplication app(argc, argv);
 
    TextEdit widget("comman-prompt>");
    widget.show();
 
    return app.exec();
}
 
#include "main.moc"

#include <QtGui>
#include <QtCore>
#include <QtWidgets>

class TextEdit : public QTextEdit
{
    Q_OBJECT
public:
    explicit TextEdit(const QString & prompt, QWidget * parent = 0)
        : QTextEdit(parent)
        , mPrompt(prompt)
        , mCount(0)
    {
        append(mPrompt);
    }

protected:
    void keyPressEvent(QKeyEvent * event)
    {
        if((event->key() == Qt::Key_Up)   or
           (event->key() == Qt::Key_Down) or
           (event->key() == Qt::Key_Left) or
           (event->key() == Qt::Key_Right))
        {
            return;

        }
        else if(event->key() == Qt::Key_Return)
        {
            append(mPrompt);
            mCount = 0;
            return;
        }
        else if(event->key() == Qt::Key_Backspace)
        {
            if(mCount > 0)
                mCount--;
            else
                return;
        }
        else if((event->key() & Qt::Key_Escape) == Qt::Key_Escape)
        {
            return;
        }
        else
        {
            mCount++;
        }

        return QTextEdit::keyPressEvent(event);
    }

private:
    QString mPrompt;
    unsigned int mCount;
};

int main(int argc, char ** argv)
{
    QApplication app(argc, argv);

    TextEdit widget("comman-prompt>");
    widget.show();

    return app.exec();
}

#include "main.moc"

To copy to clipboard, switch view to plain text mode 

[prab]

Thanks A lot...I modified my code according to your suggestion and its working fine. But I am getting another issue. When I am typing some thing, it is recognizing the input as a string but coping some thing and pasting in the command prompt is not recognized as keyboard event and not generating the corresponding keys. Below is the example.

command_prompt>ls -l (pasted not typed)

here the characters "ls -l" since copied and pasted, the respective key events are not getting generated and not recognized as a command.

Need your valuable suggestion for this to be solved.

Thanks,
prabhu

[Santosh Reddy]

#include <QtGui>
#include <QtCore>
#include <QtWidgets>
 
class TextEdit : public QTextEdit
{
    Q_OBJECT
public:
    explicit TextEdit(const QString & prompt, QWidget * parent = 0)
        : QTextEdit(parent)
        , mPrompt(prompt)
        , mCount(0)
    {
        append(mPrompt);
    }
 
protected:
    void keyPressEvent(QKeyEvent * event)
    {
        qDebug() << mCount;
 
        if((event->key() == Qt::Key_Up)   or
           (event->key() == Qt::Key_Down) or
           (event->key() == Qt::Key_Left) or
           (event->key() == Qt::Key_Right))
        {
            return;
 
        }
        else if(event->key() == Qt::Key_Return)
        {
            append(mPrompt);
            mCount = 0;
            return;
        }
        else if(event->key() == Qt::Key_Backspace)
        {
            if(mCount > 0)
                mCount--;
            else
                return;
        }
        else if(event->key() == Qt::Key_V)
        {
            if(event->modifiers() & Qt::ControlModifier)
                mCount += QApplication::clipboard()->text().length();
        }
        else if(event->key() == Qt::Key_Insert)
        {
            if(event->modifiers() & Qt::ShiftModifier)
                mCount += QApplication::clipboard()->text().length();
        }
        else if((event->key() & Qt::Key_Escape) == Qt::Key_Escape)
        {
            return;
        }
        else
        {
            mCount++;
        }
 
        return QTextEdit::keyPressEvent(event);
    }
 
private:
    QString mPrompt;
    unsigned int mCount;
};
 
int main(int argc, char ** argv)
{
    QApplication app(argc, argv);
 
    TextEdit widget("comman-prompt>");
    widget.show();
 
    return app.exec();
}
 
#include "main.moc"

#include <QtGui>
#include <QtCore>
#include <QtWidgets>

class TextEdit : public QTextEdit
{
    Q_OBJECT
public:
    explicit TextEdit(const QString & prompt, QWidget * parent = 0)
        : QTextEdit(parent)
        , mPrompt(prompt)
        , mCount(0)
    {
        append(mPrompt);
    }

protected:
    void keyPressEvent(QKeyEvent * event)
    {
        qDebug() << mCount;

        if((event->key() == Qt::Key_Up)   or
           (event->key() == Qt::Key_Down) or
           (event->key() == Qt::Key_Left) or
           (event->key() == Qt::Key_Right))
        {
            return;

        }
        else if(event->key() == Qt::Key_Return)
        {
            append(mPrompt);
            mCount = 0;
            return;
        }
        else if(event->key() == Qt::Key_Backspace)
        {
            if(mCount > 0)
                mCount--;
            else
                return;
        }
        else if(event->key() == Qt::Key_V)
        {
            if(event->modifiers() & Qt::ControlModifier)
                mCount += QApplication::clipboard()->text().length();
        }
        else if(event->key() == Qt::Key_Insert)
        {
            if(event->modifiers() & Qt::ShiftModifier)
                mCount += QApplication::clipboard()->text().length();
        }
        else if((event->key() & Qt::Key_Escape) == Qt::Key_Escape)
        {
            return;
        }
        else
        {
            mCount++;
        }

        return QTextEdit::keyPressEvent(event);
    }

private:
    QString mPrompt;
    unsigned int mCount;
};

int main(int argc, char ** argv)
{
    QApplication app(argc, argv);

    TextEdit widget("comman-prompt>");
    widget.show();

    return app.exec();
}

#include "main.moc"

To copy to clipboard, switch view to plain text mode 

[prab]

Hi,
First of all I thank you for your reply that helped me a lot for solving the issue I faced. The previous copy-paste option is working now very fine based upon the suggestion u gave. but the mouse clik option is not working. I mean when I am pasting using mouse the respected key events for the word I pasted using mouse are not getting generated and the command is not working. Need your valuable suggestion to get out of this issue

command_prompt>ls -l (pasted using mouse)

The key events for command "ls -l" is not getting generated and the command is not getting recognised.


Thanks,
prabhu

[PstdEr]

Hi Santhosh,
I am sorry for replying to little old thread , but i am struggling for few days to solve this problem and i am asking this because you mentioned Qt5 in the post, thought you have Qt5 installed on your system and may be you will try running my program and provide some suggestion.


http://www.qtcentre.org/threads/5492...dwidgets/page2