气泡聊天框设计

我们期待实现如下绿色的气泡对话框

https://cdn.llfc.club/1718417551126.jpg

对于我们自己发出的信息，我们可以实现这样一个网格布局管理

https://cdn.llfc.club/1718423760358.jpg

NameLabel用来显示用户的名字，Bubble用来显示聊天信息，Spacer是个弹簧，保证将NameLabel,IconLabel，Bubble等挤压到右侧。

如果是别人发出的消息，我们设置这样一个网格布局

https://cdn.llfc.club/1718497364660.jpg

下面是实现布局的核心代码

ChatItemBase::ChatItemBase(ChatRole role, QWidget *parent)
    : QWidget(parent)
    , m_role(role)
{
    m_pNameLabel    = new QLabel();
    m_pNameLabel->setObjectName("chat_user_name");
    QFont font("Microsoft YaHei");
    font.setPointSize(9);
    m_pNameLabel->setFont(font);
    m_pNameLabel->setFixedHeight(20);
    m_pIconLabel    = new QLabel();
    m_pIconLabel->setScaledContents(true);
    m_pIconLabel->setFixedSize(42, 42);
    m_pBubble       = new QWidget();
    QGridLayout *pGLayout = new QGridLayout();
    pGLayout->setVerticalSpacing(3);
    pGLayout->setHorizontalSpacing(3);
    pGLayout->setMargin(3);
    QSpacerItem*pSpacer = new QSpacerItem(40, 20, QSizePolicy::Expanding, QSizePolicy::Minimum);
    if(m_role == ChatRole::Self)
    {
        m_pNameLabel->setContentsMargins(0,0,8,0);
        m_pNameLabel->setAlignment(Qt::AlignRight);
        pGLayout->addWidget(m_pNameLabel, 0,1, 1,1);
        pGLayout->addWidget(m_pIconLabel, 0, 2, 2,1, Qt::AlignTop);
        pGLayout->addItem(pSpacer, 1, 0, 1, 1);
        pGLayout->addWidget(m_pBubble, 1,1, 1,1);
        pGLayout->setColumnStretch(0, 2);
        pGLayout->setColumnStretch(1, 3);
    }else{
        m_pNameLabel->setContentsMargins(8,0,0,0);
        m_pNameLabel->setAlignment(Qt::AlignLeft);
        pGLayout->addWidget(m_pIconLabel, 0, 0, 2,1, Qt::AlignTop);
        pGLayout->addWidget(m_pNameLabel, 0,1, 1,1);
        pGLayout->addWidget(m_pBubble, 1,1, 1,1);
        pGLayout->addItem(pSpacer, 2, 2, 1, 1);
        pGLayout->setColumnStretch(1, 3);
        pGLayout->setColumnStretch(2, 2);
    }
    this->setLayout(pGLayout);
}

设置用户名和头像

void ChatItemBase::setUserName(const QString &name)
{
    m_pNameLabel->setText(name);
}

void ChatItemBase::setUserIcon(const QPixmap &icon)
{
    m_pIconLabel->setPixmap(icon);
}

因为我们还要定制化实现气泡widget，所以要写个函数更新这个widget

void ChatItemBase::setWidget(QWidget *w)
{
   QGridLayout *pGLayout = (qobject_cast<QGridLayout *>)(this->layout());
   pGLayout->replaceWidget(m_pBubble, w);
   delete m_pBubble;
   m_pBubble = w;
}

聊天气泡

我们的消息分为几种，文件，文本，图片等。所以先实现BubbleFrame作为基类

class BubbleFrame : public QFrame
{
    Q_OBJECT
public:
    BubbleFrame(ChatRole role, QWidget *parent = nullptr);
    void setMargin(int margin);
    //inline int margin(){return margin;}
    void setWidget(QWidget *w);
protected:
    void paintEvent(QPaintEvent *e);
private:
    QHBoxLayout *m_pHLayout;
    ChatRole m_role;
     int      m_margin;
};

BubbleFrame基类构造函数创建一个布局，要根据是自己发送的消息还是别人发送的，做margin分布

const int WIDTH_SANJIAO  = 8;  //三角宽
BubbleFrame::BubbleFrame(ChatRole role, QWidget *parent)
    :QFrame(parent)
    ,m_role(role)
    ,m_margin(3)
{
    m_pHLayout = new QHBoxLayout();
    if(m_role == ChatRole::Self)
        m_pHLayout->setContentsMargins(m_margin, m_margin, WIDTH_SANJIAO + m_margin, m_margin);
    else
        m_pHLayout->setContentsMargins(WIDTH_SANJIAO + m_margin, m_margin, m_margin, m_margin);

    this->setLayout(m_pHLayout);
}

将气泡框内设置文本内容，或者图片内容，所以实现了下面的函数

void BubbleFrame::setWidget(QWidget *w)
{
    if(m_pHLayout->count() > 0)
        return ;
    else{
        m_pHLayout->addWidget(w);
    }
}

接下来绘制气泡

void BubbleFrame::paintEvent(QPaintEvent *e)
{
    QPainter painter(this);
    painter.setPen(Qt::NoPen);

    if(m_role == ChatRole::Other)
    {
        //画气泡
        QColor bk_color(Qt::white);
        painter.setBrush(QBrush(bk_color));
        QRect bk_rect = QRect(WIDTH_SANJIAO, 0, this->width()-WIDTH_SANJIAO, this->height());
        painter.drawRoundedRect(bk_rect,5,5);
        //画小三角
        QPointF points[3] = {
            QPointF(bk_rect.x(), 12),
            QPointF(bk_rect.x(), 10+WIDTH_SANJIAO +2),
            QPointF(bk_rect.x()-WIDTH_SANJIAO, 10+WIDTH_SANJIAO-WIDTH_SANJIAO/2),
        };
        painter.drawPolygon(points, 3);
    }
    else
    {
        QColor bk_color(158,234,106);
        painter.setBrush(QBrush(bk_color));
        //画气泡
        QRect bk_rect = QRect(0, 0, this->width()-WIDTH_SANJIAO, this->height());
        painter.drawRoundedRect(bk_rect,5,5);
        //画三角
        QPointF points[3] = {
            QPointF(bk_rect.x()+bk_rect.width(), 12),
            QPointF(bk_rect.x()+bk_rect.width(), 12+WIDTH_SANJIAO +2),
            QPointF(bk_rect.x()+bk_rect.width()+WIDTH_SANJIAO, 10+WIDTH_SANJIAO-WIDTH_SANJIAO/2),
        };
        painter.drawPolygon(points, 3);

    }

    return QFrame::paintEvent(e);
}

绘制的过程很简单，先创建QPainter，然后设置NoPen,表示不绘制轮廓线，接下来用设置指定颜色的画刷绘制图形，我们先绘制矩形再绘制三角形。

对于文本消息的绘制

TextBubble::TextBubble(ChatRole role, const QString &text, QWidget *parent)
    :BubbleFrame(role, parent)
{
    m_pTextEdit = new QTextEdit();
    m_pTextEdit->setReadOnly(true);
    m_pTextEdit->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    m_pTextEdit->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    m_pTextEdit->installEventFilter(this);
    QFont font("Microsoft YaHei");
    font.setPointSize(12);
    m_pTextEdit->setFont(font);
    setPlainText(text);
    setWidget(m_pTextEdit);
    initStyleSheet();
}

setPlainText设置文本最大宽度

void TextBubble::setPlainText(const QString &text)
{
    m_pTextEdit->setPlainText(text);
    //m_pTextEdit->setHtml(text);
    //找到段落中最大宽度
    qreal doc_margin = m_pTextEdit->document()->documentMargin();
    int margin_left = this->layout()->contentsMargins().left();
    int margin_right = this->layout()->contentsMargins().right();
    QFontMetricsF fm(m_pTextEdit->font());
    QTextDocument *doc = m_pTextEdit->document();
    int max_width = 0;
    //遍历每一段找到 最宽的那一段
    for (QTextBlock it = doc->begin(); it != doc->end(); it = it.next())    //字体总长
    {
        int txtW = int(fm.width(it.text()));
        max_width = max_width < txtW ? txtW : max_width;                 //找到最长的那段
    }
    //设置这个气泡的最大宽度 只需要设置一次
    setMaximumWidth(max_width + doc_margin * 2 + (margin_left + margin_right));        //设置最大宽度
}

我们拉伸的时候要调整气泡的高度,这里重写事件过滤器

bool TextBubble::eventFilter(QObject *o, QEvent *e)
{
    if(m_pTextEdit == o && e->type() == QEvent::Paint)
    {
        adjustTextHeight(); //PaintEvent中设置
    }
    return BubbleFrame::eventFilter(o, e);
}

调整高度

void TextBubble::adjustTextHeight()
{
    qreal doc_margin = m_pTextEdit->document()->documentMargin();    //字体到边框的距离默认为4
    QTextDocument *doc = m_pTextEdit->document();
    qreal text_height = 0;
    //把每一段的高度相加=文本高
    for (QTextBlock it = doc->begin(); it != doc->end(); it = it.next())
    {
        QTextLayout *pLayout = it.layout();
        QRectF text_rect = pLayout->boundingRect();                             //这段的rect
        text_height += text_rect.height();
    }
    int vMargin = this->layout()->contentsMargins().top();
    //设置这个气泡需要的高度 文本高+文本边距+TextEdit边框到气泡边框的距离
    setFixedHeight(text_height + doc_margin *2 + vMargin*2 );
}

设置样式表

void TextBubble::initStyleSheet()
{
    m_pTextEdit->setStyleSheet("QTextEdit{background:transparent;border:none}");
}

对于图像的旗袍对话框类似，只是计算图像的宽高即可

#define PIC_MAX_WIDTH 160
#define PIC_MAX_HEIGHT 90

PictureBubble::PictureBubble(const QPixmap &picture, ChatRole role, QWidget *parent)
    :BubbleFrame(role, parent)
{
    QLabel *lb = new QLabel();
    lb->setScaledContents(true);
    QPixmap pix = picture.scaled(QSize(PIC_MAX_WIDTH, PIC_MAX_HEIGHT), Qt::KeepAspectRatio);
    lb->setPixmap(pix);
    this->setWidget(lb);

    int left_margin = this->layout()->contentsMargins().left();
    int right_margin = this->layout()->contentsMargins().right();
    int v_margin = this->layout()->contentsMargins().bottom();
    setFixedSize(pix.width()+left_margin + right_margin, pix.height() + v_margin *2);
}

发送测试

接下来在发送处实现文本和图片消息的展示，点击发送按钮根据不同的类型创建不同的气泡消息

void ChatPage::on_send_btn_clicked()
{
    auto pTextEdit = ui->chatEdit;
    ChatRole role = ChatRole::Self;
    QString userName = QStringLiteral("恋恋风辰");
    QString userIcon = ":/res/head_1.jpg";

    const QVector<MsgInfo>& msgList = pTextEdit->getMsgList();
    for(int i=0; i<msgList.size(); ++i)
    {
        QString type = msgList[i].msgFlag;
        ChatItemBase *pChatItem = new ChatItemBase(role);
        pChatItem->setUserName(userName);
        pChatItem->setUserIcon(QPixmap(userIcon));
        QWidget *pBubble = nullptr;
        if(type == "text")
        {
            pBubble = new TextBubble(role, msgList[i].content);
        }
        else if(type == "image")
        {
            pBubble = new PictureBubble(QPixmap(msgList[i].content) , role);
        }
        else if(type == "file")
        {

        }
        if(pBubble != nullptr)
        {
            pChatItem->setWidget(pBubble);
            ui->chat_data_list->appendChatItem(pChatItem);
        }
    }
}

效果展示

https://cdn.llfc.club/1718499438435.jpg

源码和视频

https://www.bilibili.com/video/BV1Mz4218783/?vd_source=8be9e83424c2ed2c9b2a3ed1d01385e9

源码链接

https://gitee.com/secondtonone1/llfcchat

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