QT编辑器智能按钮

Question

我有一个带有按钮的工具栏:撤消、重做、剪切、复制、粘贴，如下所示：

editmenu = menuBar()->addMenu(QObject::tr("&Edit"));
undoact = editmenu->addAction(QIcon(":images/undo.png"), QObject::tr("&Undo"));
QObject::connect(editwin, SIGNAL(undoAvailable(bool)), undoact, SLOT(setEnabled(bool)));
QObject::connect(undoact, SIGNAL(triggered()), editwin, SLOT(undo()));
undoact->setShortcuts(QKeySequence::keyBindings(QKeySequence::Undo));
undoact->setEnabled(false);
redoact = editmenu->addAction(QIcon(":images/redo.png"), QObject::tr("&Redo"));
QObject::connect(editwin, SIGNAL(redoAvailable(bool)), redoact, SLOT(setEnabled(bool)));
QObject::connect(redoact, SIGNAL(triggered()), editwin, SLOT(redo()));
redoact->setShortcuts(QKeySequence::keyBindings(QKeySequence::Redo));
redoact->setEnabled(false);
editmenu->addSeparator();
cutact = editmenu->addAction(QIcon(":images/cut.png"), QObject::tr("Cu&t"));
cutact->setShortcuts(QKeySequence::keyBindings(QKeySequence::Cut));
cutact->setEnabled(false);
copyact = editmenu->addAction(QIcon(":images/copy.png"), QObject::tr("&Copy"));
copyact->setShortcuts(QKeySequence::keyBindings(QKeySequence::Copy));
copyact->setEnabled(false);
pasteact = editmenu->addAction(QIcon(":images/paste.png"), QObject::tr("&Paste"));
pasteact->setShortcuts(QKeySequence::keyBindings(QKeySequence::Paste));

我要：

1. 只有当剪贴板包含文本时才启用“粘贴”按钮
2. 由于某些原因，我需要禁用所有的按钮一段有限的时间。在此之后，我想启用所有按钮。但当我启用时，每个按钮将根据他的情况启用/禁用(例如。只有当有要撤消的内容时才启用撤消按钮，只有当有可以粘贴的文本时才启用粘贴按钮.)

你建议我怎么做？最聪明/最简单的方法是什么？

Answer 1

http://doc.qt.io/qt-5/qclipboard.html#signals

http://doc.qt.io/qt-5/qclipboard.html#details

创建从QClipboard对象到工具栏/主窗口类中的处理程序槽的连接。然后，在处理程序槽中，执行希望发生在工具栏按钮上的逻辑。

例如：

http://doc.qt.io/qt-5/qclipboard.html#dataChanged

// in your constructor after creating your buttons:
QObject::connect(qApp->clipboard(), SIGNAL(dataChanged()), 
    this, SLOT(onClipboardDataChanged()));

// and then make another connection for the other relevant clipboard signal...
// selectionChanged()

然后在后面的插槽里：

void MainWindow::onClipboardDataChanged()
{
     const QClipboard *clipboard = QApplication::clipboard();
     const QMimeData *mimeData = clipboard->mimeData();

     pasteact->setEnabled(mimeData->hasText());
     // or you could check the length of the text to see if it is non zero.
}

若要同时禁用/重命名所有按钮，请禁用父对象。

editToolbar->setEnabled(false);
//... after some period of time or transactions...
editToolbar->setEnabled(true);

但这可能不会禁用内置加速器的复制，剪切和粘贴。要想关闭这些键盘快捷键，您可能需要在应用程序上设置一个事件过滤器。

http://doc.qt.io/qt-5/accelerators.html

http://doc.qt.io/qt-5/qobject.html#eventFilter

http://doc.qt.io/qt-5/qobject.html#installEventFilter

希望这能有所帮助。

PS。我还没测试过这段代码。读读医生。祝好运。