Paste event in Qt

I want to build a structured document editor using Qt. The base concept for v1 is nested sections, each sectio开发者_开发百科n having a title and one or more paragraphs. Sections and paragraphs are distinct visual units (probably via background shading). I also need to be able to store character-level semantics (ie: this run of text is associated with reference X). If I wanted to build a read-only view of this it would be doable with QFrame for the sections and a QLabel for each title and each paragraph. To make this editable I'm pretty sure I can capture all keyboard events to the window and implement a cursored text-entry-and-editing feel that way.

What I'm having trouble with is how to handle copy/paste.

I want the clipboard interactions to feel native: that is, ctrl+c/v on window, command+c/v on OSX, ctrl+c/v for clipboard on X, select to copy for PRIMARY on X, middle click to paste for PRIMARY on X, etc.

The standard text editing controls in Qt handle all of this just fine. I'm wondering if there is some sort of "paste event" or similar that I can grab to implement the same thing in my custom widget? Is there another way?

For native keyboard shortcuts, you can add them to menu items:

ui->actionCut->setShortcut(QKeySequence::Cut);
ui->actionCopy->setShortcut(QKeySequence::Copy);
ui->actionInsert_empty_row->setShortcut(Qt::Key_Insert);
ui->actionPaste->setShortcut(QKeySequence::Paste);
ui->actionRemove->setShortcut(QKeySequence::Delete);

See QKeySequence docs

There's no paste signal/event as far as i know to listen to, though there's nothing stopping you from taking a sneak look at how the paste() slot is implemented in widgets like QLineEdit and implement your own if possible. The afferent signal is not that important, since it's just a signal and you can trigger that whenever you desire(eg. Ctrl+v, context menu or program menu).

LE: If i think better, you might be thinking this the wrong way, you don't need a signal, you just need the slot that you can call whenever the action is called by any means you wish(eg. ctrl+v). Once you have the slot(QClipboard), it's just a matter of properly connecting it to the desired triggering actions/signals.

I'm not completely sure why you would want to do it with a QLabel and then capture the keys when there are already classes that handle text edition for you (and you can even override the key pressed funcionality)

If you want to have editable text, you could use a QTextEdit or a QPlainTextEdit and those classes already handle the copy-paste functionality (even with right click menu and everything).

If you want to add special a special behavior to your copy and paste, you can override the Mime functions:

//in your header file, add
void insertFromMimeData(const QMimeData *source) override;  // override for paste
QMimeData * createMimeDataFromSelection() const override;   // override for copy

// in the cpp:
//it would be something like this:
void YourTextField::insertFromMimeData(const QMimeData *source) {
    // Do something special on the paste event, maybe even create your own "source"

    //call the base class insert
    QPlainTextEdit::insertFromMimeData(source);
}

Note: I'm not 100% with the copy, since I only overrode paste, but I'm almost certain that that's the right function.