QML 中调用本地标准的对话框如：QFileDialog QFontDialog Google搜索关键字qml qfiledialog (Qt5)

其实最为重要的一点，就是App的类型：

Qt5 中包括：

QObject ->  QCoreApplication -> QGuiApplication -> QApplication

一般，QML的程序使用 QGuiApplication，如果使用QGuiApplication的话，那么QtWidget的相关类就不能运行正常了。

需要使用QApplication类来处理，这样，QtWidget的相关类就可以使用了。

特别是我们对标准对话框（QFileDialog\ QFontDialog \ QColorDialog）等等

下面上代码：

main.cpp

=====================================================================

//![0]

#include "piechart.h"

#include <QtQuick/QQuickView>

#include <QGuiApplication>

#include <QApplication>

int main(int argc, char *argv[])

{

 QApplication app(argc, argv);

 qmlRegisterType<PieChart>("Charts", 1, 0, "PieChart");

 QQuickView view;

 view.setResizeMode(QQuickView::SizeRootObjectToView);

 view.setSource(QUrl::fromLocalFile("app.qml"));

 view.show();

 return app.exec();

}

//![0]

=======================================================================================

PieChart.h

=======================================================================================

#ifndef PIECHART_H
 
#define PIECHART_H
 

 
#include <QtQuick/QQuickPaintedItem>
 
#include <QColor>
 

 
//![0]
 
class PieChart : public QQuickPaintedItem
 
{
 
//![0]
 
 Q_OBJECT
 
 Q_PROPERTY(QString name READ name WRITE setName)
 
 Q_PROPERTY(QColor color READ color WRITE setColor)
 

 
//![1]
 
public:
 
//![1]
 

 
 PieChart(QQuickItem *parent = 0);
 

 
 QString name() const;
 
 void setName(const QString &name);
 

 
 QColor color() const;
 
 void setColor(const QColor &color);
 

 
 void paint(QPainter *painter);
 

 
//![2]
 
 Q_INVOKABLE void clearChart();
 

 
signals:
 
 void chartCleared();
 
//![2]
 

 
private:
 
 QString m_name;
 
 QColor m_color;
 

 
//![3]
 
};
 
//![3]
 

 
#endif

========================================================================================

PieChart.cpp

========================================================================================

#include "piechart.h"
 
#include <QPainter>
 

 
#include <QFileDialog>
 

 
PieChart::PieChart(QQuickItem *parent)
 
 : QQuickPaintedItem(parent)
 
{
 
}
 

 
QString PieChart::name() const
 
{
 
 return m_name;
 
}
 

 
void PieChart::setName(const QString &name)
 
{
 
 m_name = name;
 
}
 

 
QColor PieChart::color() const
 
{
 
 return m_color;
 
}
 

 
void PieChart::setColor(const QColor &color)
 
{
 
 m_color = color;
 
}
 

 
void PieChart::paint(QPainter *painter)
 
{
 
 QPen pen(m_color, 2);
 
 painter->setPen(pen);
 
 painter->setRenderHints(QPainter::HighQualityAntialiasing, true);
 
 painter->drawPie(boundingRect(), 90 * 16, 290 * 16);
 
}
 

 
//![0]
 
void PieChart::clearChart()
 
{
 
 QString fileName = QFileDialog::getOpenFileName(0,
 
 tr("Open Image"), "", tr("Image Files (*.png *.jpg *.bmp)"));
 
 setColor(QColor(Qt::transparent));
 
 update();
 

 
 emit chartCleared();
 
}
 
//![0]
 

========================================================================================

app.qml

========================================================================================

 
//![0]
 
import Charts 1.0
 
import QtQuick 2.0
 

 
Item {
 
 width: 300; height: 200
 

 
 PieChart {
 
 id: aPieChart
 
 anchors.centerIn: parent
 
 width: 100; height: 100
 
 color: "red"
 

 
 onChartCleared: console.log("The chart has been cleared")
 
 }
 

 
 MouseArea {
 
 anchors.fill: parent
 
 onClicked: aPieChart.clearChart()
 
 }
 

 
 Text {
 
 anchors { bottom: parent.bottom; horizontalCenter: parent.horizontalCenter; bottomMargin: 20 }
 
 text: "Click anywhere to clear the chart"
 
 }
 
}
 
//![0]