Qt浅谈之三十九圆形进度条

一、简介

        Qt下进度条一般都是水平或垂直的，有时需要一个椭圆或圆来动态显示进度，或用此来显示存储百分比，都是比较适用的。

二、详解

1、代码

（1）widgetdisplay.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QtCore>
#include <QtGui>

class StorageDisplay : public QWidget
{
    Q_OBJECT
public:
    StorageDisplay(QWidget *parent = 0);
    ~StorageDisplay();
    void setUsedValue(int value);
    void setSize(int width, int height);
protected:
    void paintEvent(QPaintEvent *event);
    void resizeEvent (QResizeEvent * event);
    void mousePressEvent(QMouseEvent *event);
    void mouseMoveEvent(QMouseEvent *event);
    void mouseReleaseEvent(QMouseEvent *event);
    void showEvent(QShowEvent *event);
    void hideEvent(QHideEvent *event);

private slots:
    void slotUpdateTimer();

private:
    QPoint beginDrag;
    bool bPressFlag;

    QPixmap backGround;
    int userdVaule;
    int currentValue;
    QLabel *startValueLabel;
    QLabel *endValueLabel;
    QLabel *dispayValueLabel;

    QTimer *updateTimer;
};

#endif // WIDGET_H

（2）widgetdisplay.cpp

#include "widgetdisplay.h"

StorageDisplay::StorageDisplay(QWidget *parent)
    : QWidget(parent, Qt::FramelessWindowHint)
    , bPressFlag(false)
    , currentValue(0)
{
    QTextCodec *codec = QTextCodec::codecForName("utf8");
    QTextCodec::setCodecForLocale(codec);
    QTextCodec::setCodecForCStrings(codec);
    QTextCodec::setCodecForTr(codec);
    resize(167, 167);
    setAutoFillBackground(false);
    QPalette pal = palette();
    pal.setColor(QPalette::Background, QColor(0xFF,0xFF,0xFF,0xFF));
    setPalette(pal);

    startValueLabel = new QLabel(tr("0%"), this);
    startValueLabel->setFont(QFont("Arial", 11, QFont::Normal));
    startValueLabel->setStyleSheet("color:#898989");

    endValueLabel = new QLabel(tr("100%"),this);
    endValueLabel->setFont(QFont("Arial", 11, QFont::Normal));
    endValueLabel->setStyleSheet("color:#898989");

    dispayValueLabel = new QLabel(this);
    dispayValueLabel->setStyleSheet("color:#349BDA");

    updateTimer = new QTimer(this);
    updateTimer->setInterval(20);
    connect(updateTimer, SIGNAL(timeout()), this, SLOT(slotUpdateTimer()));
}

StorageDisplay::~StorageDisplay()
{
    if (updateTimer->isActive()) {
        updateTimer->stop();
    }
    currentValue = 0;
}

void StorageDisplay::setUsedValue(int value)
{
    userdVaule = value;
}

void StorageDisplay::showEvent(QShowEvent *event)
{
    updateTimer->start();
    currentValue = 0;
}

void StorageDisplay::hideEvent(QHideEvent *event)
{
    if (updateTimer->isActive()) {
        updateTimer->stop();
    }
    currentValue = 0;
}

void StorageDisplay::slotUpdateTimer()
{
    if (currentValue >= userdVaule) {
        updateTimer->stop();
        return;
    }
    currentValue++;
    update();
}

void StorageDisplay::paintEvent(QPaintEvent *event)
{

    QPainter painter(this);
    QColor usedColor(165, 220, 62);
    QColor freeColor(215, 215, 215);
    painter.drawPixmap(QRect((width() - backGround.width())/2 , (height() - backGround.height())/2, backGround.width(), backGround.height()) , backGround);

    painter.translate(width() / 2, height() / 2);
    painter.setRenderHint(QPainter::Antialiasing);
    painter.setRenderHint(QPainter::SmoothPixmapTransform);
    painter.save();
    painter.rotate(42);
    painter.setPen(QPen(usedColor, 2));
    for (int i = 0; i < currentValue ; ++i) {
        painter.drawLine(0, 70, 0, 80);
        painter.rotate(2.8);
    }
    painter.setPen(QPen(freeColor, 3));
    for (int i = currentValue; i < 100 ; ++i) {
        painter.drawLine(0, 70, 0, 80);
        painter.rotate(2.8);
    }
    if (currentValue == 0) {
        dispayValueLabel->setFont(QFont("Arial", 12, QFont::Bold));
        dispayValueLabel->setText(tr("unconfig"));
    }
    else {
        dispayValueLabel->setFont(QFont("Arial", 15, QFont::Bold));
        dispayValueLabel->setText(tr("%1%").arg(currentValue));
    }
    QFontMetrics metrics(dispayValueLabel->font());
    int textwidth = metrics.width(dispayValueLabel->text());
    int textheight = metrics.height();
    dispayValueLabel->setGeometry((width() - textwidth)/2, (height() - textheight)/2 , textwidth, textheight);
    painter.restore();

    painter.translate(-width()/2, -height()/2);
    painter.setBrush(QColor(233, 233, 233));
    painter.setPen(QPen(QColor(233, 233, 233), 15));
    painter.drawEllipse(QRectF((width()/2 - 55), (height()/2 - 55), 110, 110));

    QConicalGradient conicalGradient(width()/2, height()/2, 90);
    conicalGradient.setColorAt(0, QColor(45, 204, 112));
    conicalGradient.setColorAt(1.0, QColor(51, 152, 219));
    painter.setPen(QPen(QBrush(conicalGradient), 30));
    painter.drawEllipse(QRectF((width()/2 - 35), (height()/2 - 35), 70, 70));

    painter.setPen(Qt::NoPen);
    painter.setBrush(QColor(249, 249, 249));
    painter.drawEllipse(QRectF((width()/2 - 30), (height()/2 - 30), 60, 60));
}

void StorageDisplay::resizeEvent(QResizeEvent *event)
{
    move((QApplication::desktop()->width() - width())/2,  (QApplication::desktop()->height() - height())/2);
    startValueLabel->setGeometry(35, 140, 25, 20);
    endValueLabel->setGeometry(97, 140, 50, 20);
}

/****************move everywhere*******************/
void StorageDisplay::mousePressEvent(QMouseEvent *event)
{
    bPressFlag = true;
    beginDrag = event->pos();
    QWidget::mousePressEvent(event);
}

void StorageDisplay::mouseMoveEvent(QMouseEvent *event)
{
    if (bPressFlag) {
        QPoint relaPos(QCursor::pos() - beginDrag);
        move(relaPos);
    }
    QWidget::mouseMoveEvent(event);
}

void StorageDisplay::mouseReleaseEvent(QMouseEvent *event)
{
    bPressFlag = false;
    QWidget::mouseReleaseEvent(event);
}

（3）main.cpp

#include "widgetdisplay.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    StorageDisplay w;
    w.setUsedValue(100);
    w.show();

    return a.exec();
}

（4）编译运行

三、总结

（1）上述代码已上传到CSDN：http://download.csdn.net/detail/taiyang1987912/9405639。
（2）若有问题或建议，请留言，在此感谢！