Qt绘制电池进度条（paintEvent）

#include "mybattery.h" #include <QPainter> #include <QDebug> MyBattery::MyBattery(QWidget *parent) : QWidget(parent) { initBettery(); } MyBattery::~MyBattery() { } void MyBattery::initBettery() { m_curValue = 0; m_tarValue = 0; m_isValueAdd = true; m_valueChangeTimer = new QTimer(this); m_valueChangeTimer->setInterval(10); connect(m_valueChangeTimer, SIGNAL(timeout()), this, SLOT(slotTimerOut())); } void MyBattery::paintEvent(QPaintEvent *event) { // 启用反锯齿 QPainter painter(this); painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing); // 绘制电池边框 drawBetteryBorder(&painter); // 绘制电池头部 drawBetteryHead(&painter); // 绘制电池电量 drawBetteryLevel(&painter); QWidget::paintEvent(event); } void MyBattery::drawBetteryBorder(QPainter *painter) { painter->save(); double headLength = width() / 20; // 电池头的长度 double borderLength = width() - headLength; // 电池框的长度 // 绘制电池框 int borderWidth = 5; // 电池框的边框宽度 int borderRadius = 6; // 电池框的圆角弧度 QPointF topLeft(borderWidth, borderWidth); QPointF bottomRight(borderLength, height() - borderWidth); m_batteryRect = QRectF(topLeft, bottomRight); painter->setPen(QPen(QColor(255, 255, 255), borderWidth)); painter->setBrush(Qt::NoBrush); painter->drawRoundedRect(m_batteryRect, borderRadius, borderRadius); painter->restore(); } void MyBattery::drawBetteryHead(QPainter *painter) { painter->save(); QPointF headRectTopLeft(m_batteryRect.topRight().x(), height() / 3); QPointF headRectBottomRight(width(), height() - height() / 3); QRectF headRect(headRectTopLeft, headRectBottomRight); int headRadius = 3; // 电池头部圆角弧度 painter->setPen(Qt::NoPen); painter->setBrush(QColor(255,255,255)); painter->drawRoundedRect(headRect, headRadius, headRadius); painter->restore(); } void MyBattery::drawBetteryLevel(QPainter *painter) { painter->save(); int borderWidth = 5; // 电池框的边框宽度 int levelRadius = 5; // 电量圆角弧度 double unit = (m_batteryRect.width() - (borderWidth * 2)) / 100; double width = m_curValue * unit; QPointF topLeft(m_batteryRect.topLeft().x() + borderWidth, m_batteryRect.topLeft().y() + borderWidth); QPointF bottomRight(width + borderWidth + borderWidth, m_batteryRect.bottomRight().y() - borderWidth); QRectF levelRect(topLeft, bottomRight); QLinearGradient batteryGradient(levelRect.topLeft(), levelRect.bottomLeft()); if (m_curValue <= 30) { batteryGradient.setColorAt(0.0, QColor(250, 128, 114)); batteryGradient.setColorAt(1.0, QColor(205, 92, 92)); } else { batteryGradient.setColorAt(0.0, QColor(50, 205, 50)); batteryGradient.setColorAt(1.0, QColor(60, 179, 113)); } painter->setPen(Qt::NoPen); painter->setBrush(batteryGradient); painter->drawRoundedRect(levelRect, levelRadius, levelRadius); painter->restore(); } void MyBattery::slotUpdateLevel(int value) { updateLevel((double)value); } void MyBattery::updateLevel(double value) { // 值和当前值一致则无需处理 if (value == m_curValue) { return; } // 值不在0-100的重置一下value的值 if(value < 0) { value = 0; } if(value > 100) { value = 100; } // 计算电量是增加还是减少 if (value > m_curValue) { m_isValueAdd = true; } else if(value < m_curValue) { m_isValueAdd = false; } m_tarValue = value; if(m_valueChangeTimer->isActive()) { m_valueChangeTimer->stop(); } m_valueChangeTimer->start(); } void MyBattery::slotTimerOut() { double step = 0.5; // 每次变化的值 if (m_isValueAdd) { m_curValue += step; if (m_curValue >= m_tarValue) { m_curValue = m_tarValue; m_valueChangeTimer->stop(); } } else { m_curValue -= step; if (m_curValue <= m_tarValue) { m_curValue = m_tarValue; m_valueChangeTimer->stop(); } } update(); }