Qt源码分享（五）–gif动画按钮，素材+源码

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好，废话不说，先看看效果怎么样。

1.四态绘制，normal，hover，press，disabled
2.gif 动画

说下思路：

使用QMovie播放Gif动画，每播放一次，就是图片缓存下来。在paintEvent绘制，这样就形成了动画的效果，是不是很简单。

这里我贴出主要的代码：

GifButton::GifButton(QWidget *parent, 
                     const QString &gifPath) :
                    QPushButton(parent), 
                    mGifPath(gifPath),
                    mGif(nullptr) {


    mGifFrame = QPixmap();

    mNormalBK    = QPixmap(kRESOURCE1K.arg("btn_login.png"));
    mHoverBK    = QPixmap(kRESOURCE1K.arg("btn_login_hover.png"));
    mPressBK    = QPixmap(kRESOURCE1K.arg("btn_login_push.png"));
    mDisabledBK = QPixmap(kRESOURCE1K.arg("btn_login_disabled.png"));
    mBtnStatus    = Normal;
    mTextColor    = Qt::black;

    if(! mGifPath.isEmpty()) {
        mGif = new QMovie(mGifPath, QByteArray(), this);
        connect(mGif, SIGNAL(frameChanged(int)), this, SLOT(OnIconChanged(int)));
        mGif->start();
    }

}
GifButton::~GifButton() {
    if (nullptr != mGif) {
        mGif->stop();
        delete mGif;
        mGif = nullptr;
    }
}

void GifButton::Stop() {
    mGifFrame = QPixmap();

    if (nullptr != mGif) {
        mGif->stop();
    }
    update();
}

void GifButton::Start() {
    if (nullptr != mGif) {
        mGif->start();
    }
    update();
}

void GifButton::SetText(const QString &text) {
    this->setText(text);
    update();
}

void GifButton::SetGifPath(const QString &path) {
    mGifPath = path;

    if (nullptr != mGif) {
        mGif->stop();
        delete mGif;
    }

    mGif = new QMovie(mGifPath, QByteArray(), this);
    connect(mGif, SIGNAL(frameChanged(int)), this, SLOT(OnIconChanged(int)));
}

QString GifButton::GifPath() const {
    return mGifPath;
}

void GifButton::SetEnabled(bool enable) {
    this->setEnabled(enable);
    update();
}

void GifButton::SetTextColor(QColor textColor) {
    mTextColor = textColor;
    update();
}

void GifButton::paintEvent(QPaintEvent *paintEvent) {
    const QRect rect = this->rect();

    QPainter painter(this);

    if (! this->isEnabled()) {
        painter.drawPixmap(rect, mDisabledBK);
    } else {
        if (Normal == mBtnStatus) {
            painter.drawPixmap(rect, mNormalBK);
        } else if (Hover == mBtnStatus) {
            painter.drawPixmap(rect, mHoverBK);
        } else if (Press == mBtnStatus) {
            painter.drawPixmap(rect, mPressBK);
        }
    }

    QString text = this->text();

    QFontMetrics fontWidth(this->font());  
    int width = fontWidth.width(text);
    int total_width = width;

    if (! mGifFrame.isNull()) {
        total_width += mGifFrame.width();
    }

    int text_distance = (rect.width()-total_width)/2;

    QRect text_rect(text_distance, 0, width, rect.height());

    QPen pen(mTextColor); 
    painter.setPen(pen);
    painter.drawText(text_rect, Qt::AlignHCenter | Qt::AlignVCenter, text);

    if (! mGifFrame.isNull()) {
        painter.drawPixmap(text_distance+width+2, 
                           (rect.height()-mGifFrame.height())/2, 
                           mGifFrame);
    }
}

void GifButton::enterEvent(QEvent *event) {
    mBtnStatus = Hover;
    update();
    QPushButton::enterEvent(event);
}

void GifButton::leaveEvent(QEvent *event) {
    mBtnStatus = Normal;
    update();
    QPushButton::leaveEvent(event);
}

void GifButton::mousePressEvent(QMouseEvent *event) {
    mBtnStatus = Press;
    update();
    QPushButton::mousePressEvent(event);
}

void GifButton::OnIconChanged(int) {
    QPixmap currFrame = mGif->currentPixmap();
    mGifFrame = QPixmap(currFrame.width(), currFrame.height());
    mGifFrame.fill(Qt::transparent);
    QPainter painter(&mGifFrame);
    painter.drawPixmap((mGifFrame.width()-currFrame.width()) / 2  ,
                       (mGifFrame.height()-currFrame.height()) / 2, currFrame);
    update();
}

源码参考：https://github.com/MingYueRuYa/QtDemoStydy.git GifButton 项目下。