[英]How to change QPainterPath color after clicking on QPushButton
I subclassed a QPushButton
so that I was able to re-implement the paintEvent(QPaintEvent *paint)
method also advised by the official documentation.我对
QPushButton
进行了子类化,以便能够重新实现官方文档也建议的paintEvent(QPaintEvent *paint)
方法。
Below is the sequence of operations:以下是操作顺序:
a) After I launch the application the button is below: a)启动应用程序后,按钮如下:
b) This is after I hover on it: b) 这是我在 hover 之后就可以了:
c) then I click the button: c)然后我点击按钮:
d) and finally I release the mouse d) 最后我松开鼠标
e) go away from the button e) go 远离按钮
However the problem is that the QPainterPath
with which I designed the green box it should be red after I release the button .但是问题是我设计绿色框的
QPainterPath
在我释放按钮后应该是红色的。 And, of course, it should become green again after I click again the button.当然,在我再次单击该按钮后,它应该再次变为绿色。
Below the code:代码下方:
custombutton.h自定义按钮.h
class CustomButton : public QPushButton
{
Q_OBJECT
public:
CustomButton(QWidget *parent = nullptr);
~CustomButton();
QString FirstName = "MACHINE";
QString LastName = "CONTROL";
protected:
void paintEvent(QPaintEvent *);
};
custombutton.cpp自定义按钮.cpp
CustomButton::CustomButton(QWidget *parent) : QPushButton(parent)
{
setGeometry(150, 150, 110, 110);
setAttribute(Qt::WA_TranslucentBackground);
setStyleSheet(
"QPushButton{background-color: lightGray;border: 1px solid black; border-radius: 5px;}"
"QPushButton:hover{background-color: gray;}"
"QPushButton:pressed{background-color: lightGray;}");
}
CustomButton::~CustomButton()
{
}
void CustomButton::paintEvent(QPaintEvent *paint)
{
QPushButton::paintEvent(paint);
QPainter p(this);
p.setRenderHint(QPainter::Antialiasing);
QPainterPath path;
path.addRoundedRect(QRectF(15, 15, 80, 5), 2, 2);
QPen pen(Qt::black, 0.3);
p.setPen(pen);
p.fillPath(path, Qt::darkGreen);
p.drawPath(path);
p.save();
p.drawText(QPoint(20, 60), FirstName);
p.drawText(QPoint(20, 80), LastName);
p.setFont(QFont("Arial", 10));
p.restore();
}
mainwindow.h主窗口.h
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();
public slots:
void onClickedButton();
private:
Ui::MainWindow *ui;
CustomButton *newBtn;
};
mainwindow.cpp主窗口.cpp
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
newBtn = new CustomButton(this);
newBtn->show();
connect(newBtn, &QPushButton::clicked, this, &MainWindow::onClickedButton);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::onClickedButton()
{
QPushButton* target = qobject_cast<QPushButton*>(sender());
if (target != nullptr)
{
QPainter p;
p.setRenderHint(QPainter::Antialiasing);
QPainterPath path;
path.addRoundedRect(QRectF(15, 15, 80, 5), 2, 2);
QPen pen(Qt::black, 0.3);
p.setPen(pen);
p.fillPath(path, Qt::darkRed);
p.drawPath(path);
p.save();
p.restore();
}
}
As you see in the MainWindow
I created a function onClickedButton()
which I thought would have triggered the QPainterPath
into red after clicked.正如您在
MainWindow
中看到的,我创建了一个 function onClickedButton()
,我认为单击后会触发QPainterPath
变为红色。 And in order to do that I casted it into an object (qobject_cast).为了做到这一点,我将其转换为 object (qobject_cast)。 But unfortunately it didn't work as expexted.
但不幸的是,它并没有像expexted那样工作。
The solution is to create a flag that indicates the color and call update() for repainting:解决方案是创建一个指示颜色的标志并调用 update() 进行重新绘制:
#ifndef CUSTOMBUTTON_H
#define CUSTOMBUTTON_H
#include <QPushButton>
class CustomButton : public QPushButton
{
Q_OBJECT
public:
CustomButton(QWidget *parent = nullptr);
~CustomButton();
QString FirstName = "MACHINE";
QString LastName = "CONTROL";
private Q_SLOTS:
void handleClicked();
protected:
void paintEvent(QPaintEvent *);
private:
bool state;
};
#endif // CUSTOMBUTTON_H
#include "custombutton.h"
#include <QPainter>
#include <QPainterPath>
CustomButton::CustomButton(QWidget *parent) : QPushButton(parent), state(true)
{
setGeometry(150, 150, 110, 110);
setAttribute(Qt::WA_TranslucentBackground);
setStyleSheet(
"QPushButton{background-color: lightGray;border: 1px solid black; border-radius: 5px;}"
"QPushButton:hover{background-color: gray;}"
"QPushButton:pressed{background-color: lightGray;}");
connect(this, &QPushButton::clicked, this, &CustomButton::handleClicked);
}
CustomButton::~CustomButton()
{
}
void CustomButton::handleClicked()
{
state = !state;
update();
}
void CustomButton::paintEvent(QPaintEvent *paint)
{
QPushButton::paintEvent(paint);
QPainter p(this);
p.setRenderHint(QPainter::Antialiasing);
QPainterPath path;
path.addRoundedRect(QRectF(15, 15, 80, 5), 2, 2);
QPen pen(Qt::black, 0.3);
p.setPen(pen);
p.fillPath(path, state ? Qt::darkGreen: Qt::darkRed);
p.drawPath(path);
p.drawText(QPoint(20, 60), FirstName);
p.drawText(QPoint(20, 80), LastName);
p.setFont(QFont("Arial", 10));
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.