我实现了一个drap-and-drop事件过滤器来重新排列布局中的窗口小部件,并且在一个点上将其中的几个弹出到队列中,在拖动的窗口小部件的位置添加橡皮筋,然后添加其余部分小部件回到布局(因为似乎没有一种方法可以使用QLayout接口插入'如下所示):
// HANDLE DRAG ENTER EVENTS
if (p_event->type() == QEvent::DragEnter)
{
QDragEnterEvent* dragEnterEvent = static_cast<QDragEnterEvent*>(p_event);
if (dragEnterEvent->mimeData()->hasFormat("text/plain"))
{
QString objectName = dragEnterEvent->mimeData()->text();
// findChild doesn't work on layouts because they don't ever
// inject themselves into the parent/child hierarchy, so we
// use the itemAt approach instead.
for (int i = 0; i < layout->count(); ++i)
{
dragItem = layout->itemAt(i)->widget();
if (dragItem->objectName() == objectName)
{
dragEnterEvent->acceptProposedAction();
// 'Rearrange' the widgets. This basically entails removing
// everything after the drag item, adding a placeh older, and
// then adding them back
QQueue<QWidget*> fifo;
// take everything after the drag item out
// important to have count as a local var, because otherwise it will
// decrement with every loop iteration.
int count = layout->count();
for (int j = i + 1; j < count; j++)
{
fifo.enqueue(layout->takeAt(i+1)->widget()); // the indices shift left on their own, so we only ever want to take i+1.
}
// add a 'rubber band' placeholder
m_band = new QRubberBand(QRubberBand::Rectangle);
m_band->setObjectName("placeholderBand");
m_band->setVisible(true);
m_band->setFixedSize(dragItem->size());
layout->addWidget(m_band);
// put the widgets in the fifo back in
count = fifo.count();
for(int j = 0; j < count; j++)
{
layout->addWidget(fifo.dequeue());
}
break;
}
}
}
}
这种方法的问题是添加/删除小部件会导致非常明显和令人讨厌的闪烁。有吗
QLayout
接口)不会导致闪烁?答案 0 :(得分:0)
不确定它会有所帮助,因为我在不同的上下文中使用(语义语法突出显示,在我的项目loqt中)。
#ifndef BLOCKSIG_H
#define BLOCKSIG_H
#include <QObject>
#include <QPointer>
/** temporary stop signals communication
* use with care: notably QTextEdit formatting can be lost
* on multiple changes notification
*/
struct blockSig {
blockSig(QObject* target) : target(target) { current = target->blockSignals(true); }
~blockSig() { off(); }
void off() { if (target) { target->blockSignals(current); target = 0; } }
private:
QPointer<QObject> target;
bool current;
};
#endif
示例用法,避免格式化更改时出现不需要的通知
#include "blockSig.h"
void ConsoleEdit::selectionChanged()
{
blockSig bs(this);
foreach (ExtraSelection s, extraSelections())
s.cursor.setCharFormat(s.format);
extraSelections().clear();
...
}