我正在使用Qt Quick
进行一些实验,希望为我的应用程序创建一个标题栏。因此,我继承了QQuickPaintedItem
,在其上绘制了一些内容,并希望将其用作Window
的标题栏。我使用的是Qt 5.7
。这样做成功了,但只有在一定程度上...代码后面我会解释更多;以下是我的方法:
main.cpp
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include "mycustomtitlebar.h"
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
qmlRegisterType<MyCustomTitleBar>("my.custom.lib", 1, 0, "MyCustomTitleBar");
QQmlApplicationEngine engine;
engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
return app.exec();
}
main.qml
import QtQuick 2.7
import QtQuick.Window 2.2
import my.custom.lib 1.0
Window {
id: wnd
visible: true
width: 640
height: 480
title: qsTr("Hello World")
MyCustomTitleBar {
id: titleBar
anchors.top: parent.top
anchors.left: parent.left
anchors.right: parent.right
height: 100
hostWidget: wnd
}
Rectangle {
color: "beige"
anchors.top: titleBar.bottom
anchors.left: parent.left
anchors.right: parent.right
anchors.bottom: parent.bottom
}
}
mycustomtitlebar.h
#ifndef MYCUSTOMTITLEBAR_H
#define MYCUSTOMTITLEBAR_H
#include <QQuickPaintedItem>
#include <QPoint>
class MyCustomTitleBar : public QQuickPaintedItem
{
Q_OBJECT
Q_PROPERTY(QWindow *hostWidget READ hostWidget WRITE setHostWidget)
public:
MyCustomTitleBar(QQuickItem *parent = 0);
protected:
virtual void paint(QPainter *pPainter) Q_DECL_OVERRIDE;
virtual void mousePressEvent(QMouseEvent *pEvent) Q_DECL_OVERRIDE;
virtual void mouseMoveEvent(QMouseEvent *pEvent) Q_DECL_OVERRIDE;
virtual void mouseReleaseEvent(QMouseEvent *pEvent) Q_DECL_OVERRIDE;
private:
QWindow *hostWidget() const;
void setHostWidget(QWindow *pHostWidget);
private:
QWindow *m_pHostWidget;
QPoint m_initialMousePosition;
bool m_leftMouseButtonPressed;
};
#endif // MYCUSTOMTITLEBAR_H
mycustomtitlebar.cpp
#include "mycustomtitlebar.h"
#include <QPainter>
#include <QDragMoveEvent>
#include <QWindow>
MyCustomTitleBar::MyCustomTitleBar(QQuickItem *parent)
: QQuickPaintedItem(parent),
m_leftMouseButtonPressed(false),
m_pHostWidget(Q_NULLPTR)
{
setAcceptedMouseButtons(Qt::AllButtons);
}
void MyCustomTitleBar::paint(QPainter *pPainter)
{
// Dummy drawing...
const QRect myRect(10, 10, width() - 20, height() - 20);
qDebug() << myRect;
pPainter->drawRect(myRect);
}
void MyCustomTitleBar::mousePressEvent(QMouseEvent *pEvent)
{
m_leftMouseButtonPressed = true;
m_initialMousePosition = pEvent->pos();
}
void MyCustomTitleBar::mouseMoveEvent(QMouseEvent *pEvent)
{
if (m_leftMouseButtonPressed) {
if (!m_pHostWidget) {
qDebug() << Q_FUNC_INFO << "Host widget not set. Please set host widget";
return;
}
const QPoint newMousePosition = pEvent->pos() - m_initialMousePosition + m_pHostWidget->position();
m_pHostWidget->setPosition(newMousePosition);
}
QQuickPaintedItem::mouseMoveEvent(pEvent);
}
void MyCustomTitleBar::mouseReleaseEvent(QMouseEvent *pEvent)
{
m_leftMouseButtonPressed = false;
}
QWindow *MyCustomTitleBar::hostWidget() const
{
return m_pHostWidget;
}
void MyCustomTitleBar::setHostWidget(QWindow *pHostWidget)
{
m_pHostWidget = pHostWidget;
}
现在这段代码很完美,我运行应用程序后,可以点击标题栏并拖动,整个窗口会移动到我想要的位置。
但是问题在于:如果我将`hostWidget:wnd`更改为`hostWidget:parent`,它就不再起作用了。有人能解释为什么吗?毕竟,`wnd`本来就是`parent`。
附言:
我还从Qt Creator中获得了这个非常奇怪的错误通知,但代码编译和运行都很好:
为什么?...