QT QGraphicsView QGraphicsWidget中改变窗口大小会导致部分控件丢失

xyconly 2015-03-11 11:08:33

之前搜寻各方帖子,看到说QGraphicsWidget与QWidget在部分功能上存在一些不同,例如窗口旋转缩放等情况下,于是我采用QGraphicsWidget作为基础窗口,并再次基础上进行绘图操作.但在实际操作中发现,当我用鼠标改变整体窗口时,继承自QGraphicsWidget部件会有一定几率不显示,并且没有调用该部件的paint事件?各处查找,没有找到相关原因,在此向各位求教.
以下为码源:

//main.cpp

#include <QtWidgets/QApplication>

#include "lineWidget.h"

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

{  

    QApplication app(argc, argv);  

    lineWidget* w = new lineWidget();

    w->resize(800,450);

    w->show();

    return app.exec();  

}

//lineWidget.h

#ifndef lineWidget_h

#define lineWidget_h

#include <QWidget>

#include "GraphicsView.h"

class lineWidget: public QWidget

{

    Q_OBJECT

        Q_DISABLE_COPY(timeLine)

public:

    explicit lineWidget(QWidget* parent = 0, Qt::WindowFlags f = 0);

    virtual ~lineWidget(){}

    //>获取单例

    static lineWidget* GetInstance() { return m_pInstance; }

    //>获取指针

    GraphicsView* GetlineWidgetView() { return m_plineWidgetView; }

private:

    static lineWidget* m_pInstance;

    GraphicsView* m_plineWidgetView;

};



#endif // lineWidget_h

//lineWidget.cpp

#include "lineWidget.h"

#include <QHBoxLayout>

lineWidget* lineWidget::m_pInstance = nullptr;



lineWidget::lineWidget(QWidget* parent, Qt::WindowFlags f)

    : QWidget(parent,f)

{

    Q_ASSERT(m_pInstance == nullptr);

    m_pInstance = this;

    m_plineWidgetView= new GraphicsView(this);

    QHBoxLayout* hLay = new QHBoxLayout(this);

    hLay->addWidget(m_plineWidgetView);

    setLayout(hLay);

}

//GraphicsView.h

#ifndef GRAPHICSVIEW_H

#define GRAPHICSVIEW_H



#include <QGraphicsView>

#include "GraphicsScene.h"

class GraphicsView : public QGraphicsView

{

    Q_OBJECT

public:

    explicit GraphicsView(QWidget *parent = 0);

    void setscene(GraphicsScene* pCurScene);

    GraphicsScene* getscene();

    virtual ~GraphicsView(){}

protected:

    virtual void mousePressEvent(QMouseEvent *event) override;

    virtual void mouseMoveEvent(QMouseEvent *pEvent) override;

private:

    //>加载场景

    GraphicsScene  *m_pCurScene;

};

#endif // GRAPHICSVIEW_H

//GraphicsView.cpp

#include "GraphicsView.h"



 GraphicsView::GraphicsView(QWidget *parent)

     : QGraphicsView(parent)

 {

     setWindowFlags(Qt::FramelessWindowHint);

     setBackgroundBrush(QColor(62, 62, 66));

     QRect r(-width()/2, -height()/2, width(), height());

     m_pCurScene = new GraphicsScene(r,this);

     setscene(m_pCurScene);

 }

 void GraphicsView::setscene(GraphicsScene* pCurScene)

 { 

     m_pCurScene = pCurScene;

     setScene(pCurScene); 

 }

 GraphicsScene* GraphicsView::getscene()

 { 

     return m_pCurScene;

 }

 void GraphicsView::mousePressEvent(QMouseEvent *event)

 {

     return QGraphicsView::mousePressEvent(event);

 }

 void GraphicsView::mouseMoveEvent(QMouseEvent *pEvent)

 {

     return QGraphicsView::mouseMoveEvent(pEvent);

 }

//GraphicsScene.h

#ifndef GRAPHICSSCENE_H

#define GRAPHICSSCENE_H

#include <QGraphicsScene>



class timeWidget;

class GraphicsScene : public QGraphicsScene

{

    Q_OBJECT

public:

    explicit GraphicsScene(const QRectF &sceneRect, QObject *parent = 0);

    virtual ~GraphicsScene(){}

protected:

    virtual void mousePressEvent(QGraphicsSceneMouseEvent *pEvent) override;

    virtual void mouseMoveEvent(QGraphicsSceneMouseEvent *pEvent) override;

private:

    timeWidget  *m_timeWidget;

};

#endif // GRAPHICSVIEW_H

GraphicsScene.cpp

#include "GraphicsScene.h"

#include "timeWidget.h"

#include <QGraphicsSceneMouseEvent>

#include <QGraphicsView>



GraphicsScene::GraphicsScene(const QRectF &sceneRect, QObject *parent)

    : QGraphicsScene(sceneRect,parent)

{

    m_timeWidget = new timeWidget();

    addItem(m_timeWidget);

}

void GraphicsScene::mousePressEvent(QGraphicsSceneMouseEvent *pEvent)

{

    return QGraphicsScene::mousePressEvent(pEvent);

}

void GraphicsScene::mouseMoveEvent(QGraphicsSceneMouseEvent *pEvent)

{

    return QGraphicsScene::mouseMoveEvent(pEvent);

}

//timeWidget.h

#ifndef TIMEWIDGET_H

#define TIMEWIDGET_H



#include <QGraphicsWidget>

class Stripe;

class QGraphicsLinearLayout;



class timeWidget : public QGraphicsWidget

{

    Q_OBJECT

public:

    explicit timeWidget(QGraphicsItem *parent = 0, Qt::WindowFlags wFlags = 0);

    virtual ~timeWidget(){}

protected:

    virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = 0) override;

public slots:

    void addStripe(Stripe* stripe = 0);

private:

    void CreateLayout();

private:

    QGraphicsLinearLayout *m_pLayout;

    //> 窗口集合

    QList<Stripe*>  m_stripies;

};

#endif // TIMEWIDGET_H

//timeWidget.cpp

#include "timeWidget.h"

#include "rulerwidget.h"

#include "CursorItem.h"

#include "Stripe.h"

#include <QGraphicsLinearLayout>

#include <QWidget>

//#include <QGraphicsScene>



timeWidget::timeWidget(QGraphicsItem *parent, Qt::WindowFlags wFlags)

    : QGraphicsWidget(parent,wFlags)

{

    CreateLayout();



    for( int i = 0 ; i < 5 ; i++)

        addStripe();

}



void timeWidget::CreateLayout()

{

    m_pLayout = new QGraphicsLinearLayout(Qt::Vertical,this);

    m_pLayout->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Preferred);

    m_pLayout->setContentsMargins(0, 0, 0, 0);

    m_pLayout->setSpacing(0);

    m_pLayout->setPreferredWidth(0);

    setLayout(m_pLayout);

}



void timeWidget::addStripe(Stripe* parent)

{

    Stripe *new_stripe;

    if( parent )

        new_stripe = new Stripe(parent);

    else

        new_stripe = new Stripe(this);



    new_stripe->setZValue(-10);

    new_stripe->setBackColor(QColor(37,37,38));

    m_pLayout->addItem(new_stripe);

    m_stripies << new_stripe;

}



void timeWidget::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) 

{

    QRect rc( widget->rect() );

    int stripieHeight(0);

    int i(0);

    for ( auto stripie : m_stripies )

    {

        stripie->setOriginHeight( stripieHeight );

        stripieHeight += stripie->getHeightPercentage() * rc.height()/2;

        i++;

    }

}

//Stripe.h

#ifndef TRACK_H

#define TRACK_H



#include "rectWidgetBase.h"

class Stripe : public rectWidgetBase

{

    Q_OBJECT

public:

    explicit Stripe(QGraphicsItem *parent = 0, Qt::WindowFlags wFlags = 0);

    explicit Stripe(Stripe *parent, Qt::WindowFlags wFlags = 0);

    virtual ~Stripe(){}



protected:

    virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = 0) override;

private:

    //>是否为子项

    bool m_isChildren;

};



#endif // CURSORITEM_H

//Stripe.cpp

#include "Stripe.h"

#include <QPainter>



Stripe::Stripe(QGraphicsItem *parent,Qt::WindowFlags wFlags)

    : rectWidgetBase(parent,wFlags)

    , m_isChildren(false)

{

}

Stripe::Stripe(Stripe *parent, Qt::WindowFlags wFlags)

    : rectWidgetBase(parent,wFlags)

    , m_isChildren(true)

{

}

void Stripe::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)

{

    rectWidgetBase::paint(painter,option,widget);

    // 绘制顶部边框线

    painter->setPen(QColor(0,0,0));

    painter->drawLine( rect().topLeft(), rect().topRight() );

}

//rectWidgetBase.h

#ifndef RECTWIDGETBASE_H

#define RECTWIDGETBASE_H



#include <QGraphicsWidget>



class rectWidgetBase : public QGraphicsWidget

{

    Q_OBJECT

public:

    explicit rectWidgetBase(QGraphicsItem *parent = 0, Qt::WindowFlags wFlags = 0);

    virtual ~rectWidgetBase(){}



    //>设置起始高度

    inline void setOriginHeight(int originheight){m_originheight = originheight;}

    //>设置高度占窗口百分比

    inline void setHeightPercentage(double heightPercentage){m_heightPercentage = heightPercentage;}

    //>设置宽度占窗口百分比

    inline void setWidthPercentage(double widthPercentage){m_widthPercentage = widthPercentage;}

    //>设置背景色

    inline void setBackColor(QColor color){m_backcolor = color;}



    //>获取左上角X坐标

    inline int getWidgetLeftTopX(){ return m_leftTopX; }

    //>获取左上角Y坐标

    inline int getWidgetLeftTopY(){ return m_leftTopY; }

    //>获取宽度

    inline int getWidgetWidth(){ return m_width; }

    //>获取宽度百分比

    inline double getWidthPercentage(){ return m_widthPercentage; }

    //>获取高度

    inline int getWidgetHeight(){ return m_height; }

    //>获取条形框高度百分比

    inline double getHeightPercentage(){ return m_heightPercentage; }

protected:

    //>重绘

    virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = 0) override;

private:

    //>高度占窗口百分比

    double  m_heightPercentage;

    //>初始高度

    int     m_originheight;

    //>高度

    int     m_height;

    //>宽度占窗口百分比

    double  m_widthPercentage;

    //>宽度

    int     m_width;

    //>背景色

    QColor  m_backcolor;

    //>左上角顶点X坐标

    int     m_leftTopX;

    //>左上角顶点Y坐标

    int     m_leftTopY;

};

#endif // RECTWIDGETBASE_H

//rectWidgetBase.cpp

#include "rectWidgetBase.h"

#include <QWidget>

#include <QPainter>

#include <QGraphicsScene>



rectWidgetBase::rectWidgetBase(QGraphicsItem *parent,Qt::WindowFlags wFlags)

    : QGraphicsWidget(parent,wFlags)

    , m_leftTopX(0)

    , m_leftTopY(0)

    , m_width(0)

    , m_height(0)

    , m_originheight(0)

    , m_widthPercentage(0.4)

    , m_heightPercentage(0.2)

    , m_backcolor(QColor(45,45,48))

{

    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);

    setContentsMargins(0, 0, 0, 0);

    setFlags(QGraphicsItem::ItemSendsScenePositionChanges);

}

void rectWidgetBase::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)

{

    QRect rc( widget->rect() );

    double left = rc.width() / 2 * m_widthPercentage;

    m_leftTopX = -rc.width() / 2 + left;

    m_leftTopY = -rc.height() / 2 + m_originheight;

    m_width = rc.width() - left - 1;

    m_height = rc.height() / 2 * m_heightPercentage;

    //> 绘制条形框背景

    painter->setBrush(m_backcolor);

    painter->setPen(Qt::NoPen/*QColor(0, 255, 0)*/);

    QRect r(m_leftTopX, m_leftTopY, m_width, m_height);

    resize(m_width, m_height);

    painter->drawRect( rect() );

    setPos(m_leftTopX, m_leftTopY);

    if ( scene() )

        scene()->update();

}

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xyconly 2015-03-11

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已解决,参考socrates中提到的"通过paint重绘需要手动的调用QGraphicsScene的update()函数来刷新界面" http://blog.csdn.net/socrates/article/details/1999845 考虑到可能是由于update时函数响应冲突的问题,故在timeWidget::paint函数中做相应修改(根据QT响应先后顺序,首先响应GraphicsView::paint函数,之后响应timeWidget::paint函数,之后按创建顺序响应,该问题是由于未响应paint函数引起,故在此处设置会导致强制响应各子项的函数即可)

void timeWidget::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) 
{
    if( !scene() )
        return QGraphicsWidget::paint(painter,option,widget);

    QRectF rc( scene()->sceneRect() );
    int rulerHeight(0);
    int stripieHeight(0);
    int i(0);
    for ( auto stripie : m_stripies )
    {
        int originHeight = rulerHeight + stripieHeight;
        stripieHeight += stripie->getHeightPercentage() * rc.height()/2;
        stripie->setOriginHeight( originHeight );
        i++;
        stripie->setPos( rc.width()/2 * (stripie->getWidthPercentage()-1), -rc.height()/2 + originHeight );
    }
    scene()->update(rc);
}

另外,由于sceneRect()的大小应实时随窗口改变,故应在GraphicsView中添加paint函数来随时修改大小

 void GraphicsView::paintEvent(QPaintEvent *event)
 {
     QRect r(-width()/2+2, -height()/2+2, width()-4, height()-4);//2为边距,+2使得与QGraphicsItem::paint中的widget大小保持一致
     m_pCurScene->setSceneRect(r);
     QRect re = rect();
     QGraphicsView::paintEvent(event);
 }

由于时间原因,未能自动全部显示部件的原因尚未找到,如有人知道,烦请告诉我一声,不甚感激~

xyconly 2015-03-11