Qt 自定义信号强度显示控件_qt做信号强弱

效果图

QWidget自定义信号强度显示控件，比较简单，适合初学者。
主要就是继承于QWidget， 重写paintEvent以绘制；
源码如下：

signalwidget.h

#ifndef SIGNALWIDGET_H
#define SIGNALWIDGET_H

/*!
    信号显示控件
    自适应长宽比例；
    widget 高度分为4份，信号柱由低到高使用对应份额；
    widget 宽度分为十份，四个信号柱各占一份，三个空白区域各占两份
	作者(csdn)：为啥不吃肉捏
*/

#include <QWidget>

class SignalWidget : public QWidget
{
    Q_OBJECT
public:
    explicit SignalWidget(QWidget *parent = nullptr);

    /*! 信号强度 */
    enum class SignalStrength{
        Zero,
        One,
        Two,
        Three,
        Four
    };

    /*! 设置信号强度 */
    void setSignalStrength(SignalStrength newSignalStrength);

protected:
    void paintEvent(QPaintEvent *event) override;

private:
    SignalStrength m_signalStrength;

};

#endif // SIGNALWIDGET_H
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signalwidget.cpp

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

SignalWidget::SignalWidget(QWidget *parent) : QWidget(parent)
{

}

void SignalWidget::paintEvent(QPaintEvent *event)
{
    Q_UNUSED(event);
    QPainter p(this);
    p.setRenderHint(QPainter::Antialiasing);

    //widget 高度分为4份，信号柱由低到高使用对应份额
    float hUnit = this->height() / 4.0;
    int h1 = hUnit * 1;
    int h2 = hUnit * 2;
    int h3 = hUnit * 3;
    int h4 = hUnit * 4;

    //widget 宽度分为十份，四个信号柱各占一份，三个空白区域各占两份
    float wUnit = this->width() / 10.0;
    int x1 = 1;
    int x2 = wUnit * 3;
    int x3 = wUnit * 6;
    int x4 = wUnit * 9 - 1;

    //border-radius
    int rounded = wUnit / 2.0;

    QColor havaSignal = QColor(79, 134, 210);
    QColor noSignal = Qt::gray;

    QColor colorOne, colorTwo, colorThree, colorFour;
    colorOne = noSignal;
    colorTwo = noSignal;
    colorThree = noSignal;
    colorFour = noSignal;

    switch(m_signalStrength)
    {
    case SignalStrength::Four:
        colorFour = havaSignal;
    case SignalStrength::Three:
        colorThree = havaSignal;
    case SignalStrength::Two:
        colorTwo = havaSignal;
    case SignalStrength::One:
        colorOne = havaSignal;
    default: break;
    };

    p.setPen(colorOne);
    p.setBrush(colorOne);
    p.drawRoundedRect(x1, this->height() - h1, wUnit, h1, rounded, rounded);

    p.setPen(colorTwo);
    p.setBrush(colorTwo);
    p.drawRoundedRect(x2, this->height() - h2, wUnit, h2, rounded, rounded);

    p.setPen(colorThree);
    p.setBrush(colorThree);
    p.drawRoundedRect(x3, this->height() - h3, wUnit, h3, rounded, rounded);

    p.setPen(colorFour);
    p.setBrush(colorFour);
    p.drawRoundedRect(x4, this->height() - h4, wUnit, h4, rounded, rounded);
}


void SignalWidget::setSignalStrength(SignalStrength newSignalStrength)
{
    m_signalStrength = newSignalStrength;
    this->update();
}

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使用：
我们在 ui 设计器中拖出一个widget或者在工程中 new 一个SignalWidget，在此我们使用比较快速的方式，在ui中拖出widget，并提升为 SignalWidget，然后如下设置：

ui->widget->setSignalStrength(SignalWidget::SignalStrength::Three);
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运行如下：