QT C++ - 如何引用另一个类中的小部件

Question

我正在尝试制作一个按钮,将小部件添加到布局中.

该小部件完全来自UI的另一个类.

通常我会指向另一个类(没有UI,带有小部件)的指针InkSpot *ink(类名称为InkSpot)然后我会说ui->paintAreaLayout->addWidget(ink->widget);但是那条线就会导致应用程序崩溃,如果我删除它并添加不引用该类的东西然后它不会崩溃.

我将提供大部分代码,以便您可以更好地了解我正在尝试做的事情.测试按钮位于第一个代码块的底部,该代码块是有问题的:

inkpuppet.cpp

#include "inkpuppet.h"
#include "ui_inkpuppet.h"
#include "newdialog.h"
#include "inkspot.h"

#include <Qt>
#include <QtCore>
#include <QtGui>
#include <QtWidgets>
#include <QDialog>
#include <QMainWindow>


InkPuppet::InkPuppet(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::InkPuppet)
{
    ui->setupUi(this);

    //connect the frame range boxes to the timeslider
    connect(ui->lowerFrameBox, SIGNAL(valueChanged(int)), this, SLOT(setMinimum(int)));
    connect(ui->upperFrameBox, SIGNAL(valueChanged(int)), this, SLOT(setMaximum(int)));

    //connect the menu items
    connect(ui->actionNew, SIGNAL(triggered()), this, SLOT(actionNew()));

    //connect test
    connect(ui->testButton, SIGNAL(clicked()), this, SLOT(testButton()));
}

InkPuppet::~InkPuppet()
{
    delete ui;
}

void InkPuppet::setMinimum(int value)
{
    ui->timeSlider->setMinimum(value);
}

void InkPuppet::setMaximum(int value)
{
    ui->timeSlider->setMaximum(value);
}

void InkPuppet::actionNew()
{
    NewDialog *dialog = new NewDialog;
    dialog->setModal(true);
    dialog->show();
}

void InkPuppet::testButton()
{
    ui->testButton->setText("working");
    //ui->paintAreaLayout->addWidget(ink->label);
    //qDebug() << ui->testButton;
    ui->paintAreaLayout->addWidget(ink->widget);
}

inkpuppet.h

#ifndef INKPUPPET_H
#define INKPUPPET_H

#include "inkspot.h"

#include <QMainWindow>

namespace Ui {
class InkPuppet;
}

class InkPuppet : public QMainWindow
{
    Q_OBJECT

public:
    explicit InkPuppet(QWidget *parent = 0);
    ~InkPuppet();
    InkSpot *ink;

private slots:
    void setMinimum(int value);
    void setMaximum(int value);
    void actionNew();
    void testButton();

public:
    Ui::InkPuppet *ui;
};

#endif // INKPUPPET_H

inkspot.cpp

#include "inkspot.h"
#include "inkpuppet.h"
#include "ui_inkpuppet.h"

#include <QtCore>
#include <QtGui>
#include <QWidget>
#include <QPainter>
#include <QPaintEvent>


void InkSpot::paintEvent(QPaintEvent *event)
{
    QWidget *widget = new QWidget();
    widget->setFixedSize(100, 150);
    QLabel *label = new QLabel();
    label->setText("test");
    widget->layout()->addWidget(label);
    //InkPuppet.ui->paintAreaLayout->addWidget(widget);

    QFile *brushInput; //takes raw 8 bit grayscale image, 8 bit values only
    char *brushProto;
    uchar *brushData;

    brushInput = new QFile("x:\\Development\\InkPuppet\\brush.raw"); //open the raw file
    brushInput->open(QIODevice::ReadOnly);
    QDataStream in;
    in.setDevice(brushInput);
    int size = brushInput->size(); //set size to length of raw file

    brushProto = new char[size];
    in.readRawData(brushProto, size); //read file into prototype
    brushData = new uchar[size];

    for(int i = 0; i < size; ++i)
    {
        brushData[i] = (uchar)brushProto[i]; //copy char to uchar array
    }

    QImage test(brushData, 128, 128, QImage::Format_Indexed8);
    QImage test2(128, 128, QImage::Format_ARGB32);

    QVector<QRgb> vectorColors(256); //create color table
    for(int c = 0; c < 256; c++)
    {
        vectorColors[c] = qRgb(c, c, c);
    }

    test.setColorTable(vectorColors);

    for(int iX = 0; iX < 100; ++iX)
    {
        for(int iY = 0; iY < 100; ++iY)
        {
            test2.setPixel(iX, iY, qRgba(255 - (qrand() % 100), 0 + (qrand() % 100), 0 + (qrand() % 100), qAbs((int)test.pixel(iX, iY)-255)));
        }
    }

    //final conversion for stencil and color brush
    QPixmap testPixmap = QPixmap::fromImage(test2);
    QPixmap testPixmap2 = QPixmap::fromImage(test);

    QPainter painter(this);

    painter.drawPixmap(150, 50, 100, 100, testPixmap);
    painter.drawPixmap(50, 50, 100, 100, testPixmap2);

    delete[] brushProto;
    delete[] brushData;
    delete brushInput;
}

inkspot.h

#ifndef INKSPOT_H
#define INKSPOT_H

#include <QObject>
#include <QWidget>
#include <QPainter>
#include <QPaintEvent>
#include <QLabel>

namespace Ui {
class InkSpot;
}

class InkSpot : public QWidget
{
    Q_OBJECT
public:
    explicit InkSpot(QWidget *parent = 0);
    ~InkSpot();
    void draw(QPainter *painter);
    QWidget *widget;
    QLabel *label;
signals:

public slots:

protected:
    void paintEvent(QPaintEvent *event);

private:
    Ui::InkSpot *ui;

};

#endif // INKSPOT_H

Answer 1

我认为,你的错误在另一个地方.如果使用指针 - NULL每次使用时检查它们是否相等.

我还没有ink在你的代码中找到初始化.请检查一下.

此外,不时清理您的构建 - 它可以防止一些错误.