Qt之自定义界面（QMessageBox）

简述

通过前几节的自定义窗体的学习，我们可以很容易的写出一套属于自己风格的界面框架，通用于各种窗体，比如：QWidget、QDialog、QMainWindow。

大多数窗体的实现都是采用控件堆积来完成的，只要思路清晰，再复杂的界面实现起来都游刃有余。下面我来列举一个由QMessageBox扩展的提示框-根据其源码实现思路来实现！

• 简述
• 效果
• 自定义提示框
  • 实现
  • 接口说明
  • 二次封装
  • 使用方式
• 源码学习

效果

自定义提示框

实现

message_box.h

#ifndef MESSAGE_BOX
#define MESSAGE_BOX

#include <QMessageBox>
#include <QDialogButtonBox>
#include <QGridLayout>
#include "custom_window.h"

class QLabel;

class MessageBox : public CustomWindow
{
    Q_OBJECT

public:
    explicit MessageBox(QWidget *parent = 0, const QString &title = tr("Tip"), const QString &text = "",
                        QMessageBox::StandardButtons buttons = QMessageBox::Ok, QMessageBox::StandardButton defaultButton = QMessageBox::Ok);
    ~MessageBox();
    QAbstractButton *clickedButton() const;
    QMessageBox::StandardButton standardButton(QAbstractButton *button) const;
    // 设置默认按钮
    void setDefaultButton(QPushButton *button);
    void setDefaultButton(QMessageBox::StandardButton button);
    // 设置窗体标题
    void setTitle(const QString &title);
    // 设置提示信息
    void setText(const QString &text);
    // 设置窗体图标
    void setIcon(const QString &icon);
    // 添加控件-替换提示信息所在的QLabel
    void addWidget(QWidget *pWidget);

protected:
    // 多语言翻译
    void changeEvent(QEvent *event);

private slots:
    void onButtonClicked(QAbstractButton *button);

private:
    void translateUI();
    int execReturnCode(QAbstractButton *button);

private:
    QLabel *m_pIconLabel;
    QLabel *m_pLabel;
    QGridLayout *m_pGridLayout;
    QDialogButtonBox *m_pButtonBox;
    QAbstractButton *m_pClickedButton;
    QAbstractButton *m_pDefaultButton;
};

message_box.cpp

#include <QLabel>
#include <QPushButton>
#include <QMessageBox>
#include <QCheckBox>
#include <QHBoxLayout>
#include <QEvent>
#include <QApplication>
#include "message_box.h"

MessageBox::MessageBox(QWidget *parent, const QString &title, const QString &text,
                       QMessageBox::StandardButtons buttons, QMessageBox::StandardButton defaultButton)
    : CustomWindow(parent)
{
    setWindowIcon(QIcon(":/Images/logo"));
    setWindowTitle(title);
    setMinimumSize(300, 130);
    setMinimizeVisible(false);
    setMaximizeVisible(false);
    setWidgetResizable(false);

    m_pButtonBox = new QDialogButtonBox(this);
    m_pButtonBox->setStandardButtons(QDialogButtonBox::StandardButtons(int(buttons)));
    setDefaultButton(defaultButton);

    QPushButton *pYesButton = m_pButtonBox->button(QDialogButtonBox::Yes);
    if (pYesButton != NULL)
    {
        pYesButton->setObjectName("blueButton");
        pYesButton->setStyle(QApplication::style());
    }

    m_pIconLabel = new QLabel(this);
    m_pLabel = new QLabel(this);

    QPixmap pixmap(":/Images/information");
    m_pIconLabel->setPixmap(pixmap);
    m_pIconLabel->setFixedSize(35, 35);
    m_pIconLabel->setScaledContents(true);

    m_pLabel->setAlignment(Qt::AlignLeft | Qt::AlignVCenter);
    m_pLabel->setObjectName("whiteLabel");
    m_pLabel->setOpenExternalLinks(true);
    m_pLabel->setText(text);

    m_pGridLayout = new QGridLayout();
    m_pGridLayout->addWidget(m_pIconLabel, 0, 0, 2, 1, Qt::AlignTop);
    m_pGridLayout->addWidget(m_pLabel, 0, 1, 2, 1);
    m_pGridLayout->addWidget(m_pButtonBox, m_pGridLayout->rowCount(), 0, 1, m_pGridLayout->columnCount());
    m_pGridLayout->setSizeConstraint(QLayout::SetNoConstraint);
    m_pGridLayout->setHorizontalSpacing(10);
    m_pGridLayout->setVerticalSpacing(10);
    m_pGridLayout->setContentsMargins(10, 10, 10, 10);
    m_pLayout->addLayout(m_pGridLayout);

    translateUI();

    connect(m_pButtonBox, SIGNAL(clicked(QAbstractButton*)), this, SLOT(onButtonClicked(QAbstractButton*)));
}

MessageBox::~MessageBox()
{

}

void MessageBox::changeEvent(QEvent *event)
{
    switch (event->type())
    {
    case QEvent::LanguageChange:
        translateUI();
        break;
    default:
        CustomWindow::changeEvent(event);
    }
}

void MessageBox::translateUI()
{
    QPushButton *pYesButton = m_pButtonBox->button(QDialogButtonBox::Yes);
    if (pYesButton != NULL)
        pYesButton->setText(tr("Yes"));

    QPushButton *pNoButton = m_pButtonBox->button(QDialogButtonBox::No);
    if (pNoButton != NULL)
        pNoButton->setText(tr("No"));

    QPushButton *pOkButton = m_pButtonBox->button(QDialogButtonBox::Ok);
    if (pOkButton != NULL)
        pOkButton->setText(tr("Ok"));

    QPushButton *pCancelButton = m_pButtonBox->button(QDialogButtonBox::Cancel);
    if (pCancelButton != NULL)
        pCancelButton->setText(tr("Cancel"));
}

QMessageBox::StandardButton MessageBox::standardButton(QAbstractButton *button) const
{
    return (QMessageBox::StandardButton)m_pButtonBox->standardButton(button);
}

QAbstractButton *MessageBox::clickedButton() const
{
    return m_pClickedButton;
}

int MessageBox::execReturnCode(QAbstractButton *button)
{
    int nResult = m_pButtonBox->standardButton(button);
    return nResult;
}

void MessageBox::onButtonClicked(QAbstractButton *button)
{
    m_pClickedButton = button;
    done(execReturnCode(button));
}

void MessageBox::setDefaultButton(QPushButton *button)
{
    if (!m_pButtonBox->buttons().contains(button))
        return;
    m_pDefaultButton = button;
    button->setDefault(true);
    button->setFocus();
}

void MessageBox::setDefaultButton(QMessageBox::StandardButton button)
{
    setDefaultButton(m_pButtonBox->button(QDialogButtonBox::StandardButton(button)));
}

void MessageBox::setTitle(const QString &title)
{
    setWindowTitle(title);
}

void MessageBox::setText(const QString &text)
{
    m_pLabel->setText(text);
}

void MessageBox::setIcon(const QString &icon)
{
    m_pIconLabel->setPixmap(QPixmap(icon));
}

void MessageBox::addWidget(QWidget *pWidget)
{
    m_pLabel->hide();
    m_pGridLayout->addWidget(pWidget, 0, 1, 2, 1);
}

接口说明

• CustomWindow

  主要对界面的无边框可拖动进行了封装

• MessageBox

  整体界面布局及事件处理参考了QMessageBox源码，接口包含：设置标题、提示信息、默认按钮及事件触发等操作。

二次封装

针对于各种提示框，我们可以再次进行封装，将常用的提取出来，作为全局函数来使用。

QMessageBox::StandardButton showInformation(QWidget *parent, const QString &title,
                                            const QString &text, QMessageBox::StandardButtons buttons,
                                            QMessageBox::StandardButton defaultButton)
{
    MessageBox msgBox(parent, title, text, buttons, defaultButton);
    msgBox.setIcon(":/Images/information");
    if (msgBox.exec() == -1)
        return QMessageBox::Cancel;
    return msgBox.standardButton(msgBox.clickedButton());
}

QMessageBox::StandardButton showError(QWidget *parent, const QString &title,
                                      const QString &text, QMessageBox::StandardButtons buttons,
                                      QMessageBox::StandardButton defaultButton)
{
    MessageBox msgBox(parent, title, text, buttons, defaultButton);
    msgBox.setIcon(":/Images/error");
    if (msgBox.exec() == -1)
        return QMessageBox::Cancel;
    return msgBox.standardButton(msgBox.clickedButton());
}

QMessageBox::StandardButton showSuccess(QWidget *parent, const QString &title,
                                        const QString &text, QMessageBox::StandardButtons buttons,
                                        QMessageBox::StandardButton defaultButton)
{
    MessageBox msgBox(parent, title, text, buttons, defaultButton);
    msgBox.setIcon(":/Images/success");
    if (msgBox.exec() == -1)
        return QMessageBox::Cancel;
    return msgBox.standardButton(msgBox.clickedButton());
}

QMessageBox::StandardButton showQuestion(QWidget *parent, const QString &title,
                                         const QString &text, QMessageBox::StandardButtons buttons,
                                         QMessageBox::StandardButton defaultButton)
{
    MessageBox msgBox(parent, title, text, buttons, defaultButton);
    msgBox.setIcon(":/Images/question");
    if (msgBox.exec() == -1)
        return QMessageBox::Cancel;
    return msgBox.standardButton(msgBox.clickedButton());
}

QMessageBox::StandardButton showWarning(QWidget *parent, const QString &title,
                                        const QString &text, QMessageBox::StandardButtons buttons,
                                        QMessageBox::StandardButton defaultButton)
{
    MessageBox msgBox(parent, title, text, buttons, defaultButton);
    msgBox.setIcon(":/images/warning");
    if (msgBox.exec() == -1)
        return QMessageBox::Cancel;
    return msgBox.standardButton(msgBox.clickedButton());
}

QMessageBox::StandardButton showCritical(QWidget *parent, const QString &title,
                                         const QString &text, QMessageBox::StandardButtons buttons,
                                         QMessageBox::StandardButton defaultButton)
{
    MessageBox msgBox(parent, title, text, buttons, defaultButton);
    msgBox.setIcon(":/Images/warning");
    if (msgBox.exec() == -1)
        return QMessageBox::Cancel;
    return msgBox.standardButton(msgBox.clickedButton());
}

QMessageBox::StandardButton showCheckBoxQuestion(QWidget *parent, const QString &title,
                                                 const QString &text, QMessageBox::StandardButtons buttons,
                                                 QMessageBox::StandardButton defaultButton)
{
    MessageBox msgBox(parent, title, text, buttons, defaultButton);
    msgBox.setIcon(":/Images/question");

    QCheckBox *pCheckBox = new QCheckBox(&msgBox);
    pCheckBox->setText(text);
    msgBox.addWidget(pCheckBox);
    if (msgBox.exec() == -1)
        return QMessageBox::Cancel;

    QMessageBox::StandardButton standardButton = msgBox.standardButton(msgBox.clickedButton());
    if (standardButton == QMessageBox::Yes)
    {
        return pCheckBox->isChecked() ? QMessageBox::Yes : QMessageBox::No;
    }
    return QMessageBox::Cancel;
}

使用方式

showInformation(this, QStringLiteral("提示"), QStringLiteral("这是一个普通的提示框-Information！"));
showQuestion(this, QStringLiteral("提示"), QStringLiteral("这是一个普通的提示框-Question！"));
showSuccess(this, QStringLiteral("提示"), QStringLiteral("这是一个普通的提示框-Success！"));
showError(this, QStringLiteral("提示"), QStringLiteral("这是一个普通的提示框-Error！"));

源码学习

其实Qt中有很多自带的比较好的效果，里面用了很好的实现方式，建议安装的时候把源码download下来，随时可以研究并学习。例如：D:\Qt\Qt5.5.1\5.5\Src\qtbase\src\widgets\dialogs下面包含了所有关于dialog的实现-QProgressDialog、QMessageBox、QFileDialog。。。