36、QT自定义控件

#-------------------------------------------------
#
# Project created by QtCreator 2017-07-16T19:11:59
#
#-------------------------------------------------

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = samp12_1
TEMPLATE = app

# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0


SOURCES += 
        main.cpp 
        widget.cpp 
    qmybattery.cpp

HEADERS += 
        widget.h 
    qmybattery.h

FORMS += 
        widget.ui

#include "widget.h"
#include 

int main(int argc, char *argv[])
{
   QApplication a(argc, argv);
   Widget w;
   w.show();

   return a.exec();
}

 Widget
 
  
   
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   自定义Widget组件
  
  
   
    
   
   
    
     
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      电池电量：
     
    
   
  
 
 
 
  
   QmyBattery
   QWidget
   
qmybattery.h
   1
  
 
 
 

#ifndef WIDGET_H
#define WIDGET_H

#include 

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
   Q_OBJECT

public:
   explicit Widget(QWidget *parent = 0);
   ~Widget();

private slots:
   void on_horizontalSlider_valueChanged(int value);

private:
   Ui::Widget *ui;
};

#endif // WIDGET_H

#include "widget.h"
#include "ui_widget.h"

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

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

void Widget::on_horizontalSlider_valueChanged(int value)
{
   ui->battery->setPowerLevel(value);
   QString  str=QStringLiteral("当前电量：")+QString::asprintf("%d %%",value);
   ui->LabInfo->setText(str);
}

#ifndef WBATTERY_H
#define WBATTERY_H

#include    
#include    

class QmyBattery : public QWidget
{
    Q_OBJECT
//自定义属性
    Q_PROPERTY(int  powerLevel READ powerLevel WRITE setPowerLevel NOTIFY powerLevelChanged)

private:
    QColor  mColorBack=Qt::white;//背景颜色
    QColor  mColorBorder=Qt::black;//电池边框颜色
    QColor  mColorPower=Qt::green;//电量柱颜色
    QColor  mColorWarning=Qt::red;//电量短缺时的颜色

    int mPowerLevel=60;//电量0-100
    int mWarnLevel=20;//电量低警示阈值

protected:
    void    paintEvent(QPaintEvent *event) Q_DECL_OVERRIDE;

public:
    explicit QmyBattery(QWidget *parent = 0);

    void    setPowerLevel(int pow);//设置当前电量
    int     powerLevel();

    void    setWarnLevel(int warn);//设置电量低阈值
    int     warnLevel();

    QSize   sizeHint();//报告缺省大小

signals:
    void   powerLevelChanged(int );

public slots:
};

#endif // WBATTERY_H

#include "qmybattery.h"

#include    

void QmyBattery::paintEvent(QPaintEvent *event)
{  //界面组件的绘制
    Q_UNUSED(event);

    QPainter    painter(this);
    QRect rect(0,0,width(),height()); //viewport矩形区
    painter.setViewport(rect);//设置Viewport
    painter.setWindow(0,0,120,50); // 设置窗口大小，逻辑坐标
    painter.setRenderHint(QPainter::Antialiasing);
    painter.setRenderHint(QPainter::TextAntialiasing);

//绘制电池边框
    QPen    pen;//设置画笔
    pen.setWidth(2); //线宽
    pen.setColor(mColorBorder); //划线颜色
    pen.setStyle(Qt::SolidLine);//线的类型，实线、虚线等
    pen.setCapStyle(Qt::FlatCap);//线端点样式
    pen.setJoinStyle(Qt::BevelJoin);//线的连接点样式
    painter.setPen(pen);

    QBrush  brush;//设置画刷
    brush.setColor(mColorBack); //画刷颜色
    brush.setStyle(Qt::SolidPattern); //画刷填充样式
    painter.setBrush(brush);

    rect.setRect(1,1,109,48);
    painter.drawRect(rect);//绘制电池边框

    brush.setColor(mColorBorder); //画刷颜色
    painter.setBrush(brush);
    rect.setRect(110,15,10,20);
    painter.drawRect(rect); //画电池正极头

//画电池柱
    if (mPowerLevel>mWarnLevel)
    {  //正常颜色电量柱
        brush.setColor(mColorPower); //画刷颜色
        pen.setColor(mColorPower); //划线颜色
    }
    else
    { //电量低电量柱
        brush.setColor(mColorWarning); //画刷颜色
        pen.setColor(mColorWarning); //划线颜色
    }
    painter.setBrush(brush);
    painter.setPen(pen);

    if (mPowerLevel>0)
    {
        rect.setRect(5,5,mPowerLevel,40);
        painter.drawRect(rect);//画电池柱
    }

//绘制电量百分比文字
    QFontMetrics    textSize(this->font());
    QString powStr=QString::asprintf("%d%%",mPowerLevel);
    QRect textRect=textSize.boundingRect(powStr);//得到字符串的rect

    painter.setFont(this->font());
    pen.setColor(mColorBorder); //划线颜色
    painter.setPen(pen);

    painter.drawText(55-textRect.width()/2,
               23+textRect.height()/2,
               powStr);
}

QmyBattery::QmyBattery(QWidget *parent) : QWidget(parent)
{
//    setPalette(QPalette(mColorBack));
//    setAutoFillBackground(true);
//    this->resize(120,50);
}

void QmyBattery::setPowerLevel(int pow)
{ //设置当前电量值
    mPowerLevel=pow;
    emit powerLevelChanged(pow); //触发信号
    repaint();
}

int QmyBattery::powerLevel()
{ //读取当前电量值
    return mPowerLevel;
}

void QmyBattery::setWarnLevel(int warn)
{//设置电量低阈值
    mWarnLevel=warn;
    repaint();
}

int QmyBattery::warnLevel()
{//读取电量低阈值
    return  mWarnLevel;
}

QSize QmyBattery::sizeHint()
{//报告缺省大小,调整比例
    int H=this->height();
    int W=H*12/5;
    QSize   size(W,H);
    return size;
}

源码：https://download.csdn.net/download/qq_30457077/85075848