第47课 Qt中的调色板

1. QPalette类

（1）QPalette类提供了绘制QWidget组件的不同状态所使用的颜色。

（2）QPalette对象包含了3个状态的颜色描述

　　①激活颜色组（Active）：组件获得焦点使用的颜色搭配方案

　　②非激活颜色组（Inactive）：组件失去焦点使用的颜色方案

　　③失效颜色组（Disabled）：组件处于不可用状态使用的颜色方案

2.QPalette类中颜色组用途

（1）QPalette类中的颜色组定义了组细节的颜色值

（2）QPalette::ColorRole中的常量值用于标识当前GUI界面中颜色的职责。如，QPalette::Window指窗口部件的背景色、QPalette::WindowText指前景色。QPalette指按钮的背景色、QPalette::ButtonText指按钮的前景色等。

3. 理解Qt中的调色板

（1）调色板是存储组件颜色信息的数据结构

	WindowText	Highlight	……	ButtonText
Active	black	blue	……	black
Inactive	black	Gray	……	black
Disabled	gray	Gray	……	gray
理解：	1.调色板是存储组件颜色信息的数据结构 2.组件外观所使用的颜色都位于调色板中

（2）调色板的使用方式

QPalette p = widget.palette(); //获取组件的调色板

//改变widget前景色
p.setColor(QPalette::Active, QPalette::WindowText, Qt::blue);
p.setColor(QPalette:Inactive, QPalette::WindowText, Qt::blue);

widget.setPalette(p);//更新设置

【编程实验】Qt中调色板的使用

//main.cpp

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

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

    return a.exec();
}

//Widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QPushButton>
#include <QLineEdit>
#include <QLabel>

class Widget : public QWidget
{
    Q_OBJECT

    QPushButton m_button;
    QLineEdit m_edit;
    QLabel m_label;

protected slots:
    void onButtonClicked();

public:
    Widget(QWidget *parent = );
    ~Widget();
};

#endif // WIDGET_H

//Widget.cpp

#include "Widget.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent),m_button(this),m_edit(this),m_label(this)
{
    m_label.move(, );
    m_label.resize(,);
    m_label.setText("Test");

    m_edit.move(, );
    m_edit.resize(, );

    m_button.move(, );
    m_button.resize(, );
    m_button.setText("Test");

    connect(&m_button, SIGNAL(clicked()), this, SLOT(onButtonClicked()));

    QPalette p = m_button.palette();

    p.setColor(QPalette::Active, QPalette::ButtonText, Qt::red);
    p.setColor(QPalette::Inactive, QPalette::ButtonText, Qt::red);

    m_button.setPalette(p);

    p = m_edit.palette();
    p.setColor(QPalette::Inactive, QPalette::Highlight, Qt::blue);
    p.setColor(QPalette::Inactive, QPalette::HighlightedText, Qt::white);

    m_edit.setPalette(p);
}
void Widget::onButtonClicked()
{
    QPalette p = m_label.palette();

    p.setColor(QPalette::Active, QPalette::WindowText, Qt::green);
    p.setColor(QPalette::Inactive, QPalette::WindowText, Qt::green);

    m_label.setPalette(p);
}
Widget::~Widget()
{

}

【编程实验】NotePad中查找功能的优化（失去焦点时仍高亮标识找到的文本）

//main.cpp //与上例相同

//FontDialog.h　//与上例相同

//FontDialog.cpp　//与上例相同

//MainWindow.h　//与上例相同

//MainWindowUI.cpp

#include "MainWindow.h"
#include <QMenu>
#include <QToolBar>
#include <QStatusBar>
#include <QLabel>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent),m_pFindDlg(new FindDialog(this,&mainEditor))
{
    setWindowTitle("NotePad - [ New ]");
    mainEditor.setAcceptDrops(false);//默认下，QPlainTextEdit是接收拖放事件的
                                     //其父对象会收不到“拖放”事件，这里设为false
    setAcceptDrops(true); //由MainWindow来接管拖放事件

    m_filePath = "";

    m_isTextChanged = false;
}

//二阶构造中的第2阶构造
bool MainWindow::construct()
{
    bool ret = true;

    ret = ret && initMenuBar();
    ret = ret && initToolBar();
    ret = ret && initStatusBar();
    ret = ret && initMainEditor();

    return ret;
}

MainWindow* MainWindow::NewInstance()
{
    MainWindow* ret = new MainWindow();

    if((ret == NULL) || !ret->construct())
    {
        delete ret;
        ret = NULL;
    }

    return ret;
}

//初始化菜单栏
bool MainWindow::initMenuBar()
{
    bool ret = true;
    QMenuBar* mb = menuBar(); //menuBar为QMainWindow的成员变量

    ret = ret && initFileMenu(mb);
    ret = ret && initEditMenu(mb);
    ret = ret && initFormatMenu(mb);
    ret = ret && initViewMenu(mb);
    ret = ret && initHelpMenu(mb);

    return ret;
}

//初始化工具栏
bool MainWindow::initToolBar()
{
    bool ret = true;

    QToolBar* tb = addToolBar("Tool Bar");

    tb->setIconSize(QSize(, ));

    ret = ret && initFileToolItem(tb);
    tb->addSeparator();

    ret = ret && initEditToolItem(tb);
    tb->addSeparator();

    ret = ret && initFormatToolItem(tb);
    tb->addSeparator();

    ret = ret && initViewToolItem(tb);

    return ret;
}

//初始化状态栏
bool MainWindow::initStatusBar()
{
    bool ret = true;
    QStatusBar* sb = statusBar();
    QLabel* label = new QLabel("D.T.Software");

    if( label != NULL )
    {
        statusLbl.setMinimumWidth();
        statusLbl.setAlignment(Qt::AlignCenter);
        statusLbl.setText("Ln: 1    Col: 1");

        label->setMinimumWidth();
        label->setAlignment(Qt::AlignCenter);

        sb->addPermanentWidget(new QLabel()); //添加分隔线
        sb->addPermanentWidget(&statusLbl);
        sb->addPermanentWidget(label);
    }
    else
    {
        ret = false;
    }
    return ret;
}

//初始化主文本编辑组件
bool MainWindow::initMainEditor()
{
    bool ret = true;
    QPalette p = mainEditor.palette();

    p.setColor(QPalette::Inactive, QPalette::Highlight,
               p.color(QPalette::Active, QPalette::Highlight));
    p.setColor(QPalette::Inactive, QPalette::HighlightedText,
               p.color(QPalette::Active, QPalette::HighlightedText));

    mainEditor.setPalette(p);
    mainEditor.setParent(this);

    connect(&mainEditor, SIGNAL(textChanged()), this, SLOT(onTextChanged()));
    connect(&mainEditor, SIGNAL(copyAvailable(bool)),this,SLOT(onCopyAvailable(bool)));
    connect(&mainEditor, SIGNAL(redoAvailable(bool)),this,SLOT(onRedoAvailable(bool)));
    connect(&mainEditor, SIGNAL(undoAvailable(bool)),this,SLOT(onUndoAvailable(bool)));
    connect(&mainEditor, SIGNAL(cursorPositionChanged()), this, SLOT(onCursorPositionChanged()));
    setCentralWidget(&mainEditor);

    return ret;
}

//文件(下拉)菜单
bool MainWindow::initFileMenu(QMenuBar* mb)
{
    QMenu* menu = new QMenu("File(&F)", mb);//指定parent为mb
    bool ret = (menu != NULL);

    if ( ret )
    {
        QAction* action = NULL;
        //"新建"菜单项
        ret = ret &&  makeAction(action, mb, "New(&N)", Qt::CTRL + Qt::Key_N);
        if(ret)
        {
            connect(action, SIGNAL(triggered()), this, SLOT(onFileNew()));
            menu->addAction(action); //add Action to Menu Item
        }

        //"打开"菜单项
        ret = ret &&  makeAction(action, mb, "Open(&O)...", Qt::CTRL + Qt::Key_O);
        if(ret)
        {
            connect(action, SIGNAL(triggered()), this, SLOT(onFileOpen()));
            menu->addAction(action); //add Action to Menu Item
        }

        //"保存"菜单项
        ret = ret &&  makeAction(action, mb, "Save(&S)", Qt::CTRL + Qt::Key_S);
        if(ret)
        {
            connect(action, SIGNAL(triggered()), this, SLOT(onFileSave()));
            menu->addAction(action); //add Action to Menu Item
        }

        //"另存为"菜单项
        ret = ret &&  makeAction(action, mb, );
        if(ret)
        {
            connect(action, SIGNAL(triggered()), this, SLOT(onFileSaveAs()));
            menu->addAction(action); //add Action to Menu Item
        }

        //水平分隔线
        menu->addSeparator();

        //"打印"菜单项
        ret = ret &&  makeAction(action, mb, "Print(&P)...", Qt::CTRL + Qt::Key_P);
        if(ret)
        {
            connect(action, SIGNAL(triggered()),this, SLOT(onFilePrint()));
            menu->addAction(action); //add Action to Menu Item
        }

        menu->addSeparator();

        //"退出"菜单项
        ret = ret && makeAction(action, mb, "Exit(&X)", Qt::CTRL + Qt::Key_Q);
        if(ret)
        {
            connect(action, SIGNAL(triggered()), this, SLOT(onFileExit()));
            menu->addAction(action); //add Action Item to Menu
        }
    }

    if ( ret )
    {
        mb->addMenu(menu); //add Menu to Menu Bar
    }
    else
    {
        delete menu;
    }

    return ret;
}

//“编辑”菜单
bool MainWindow::initEditMenu(QMenuBar* mb)
{
    QMenu* menu = new QMenu("Edit(&E)", mb);
    bool ret = (menu != NULL);

    if( ret )
    {
        QAction* action = NULL;

        ret = ret && makeAction(action, mb, "Undo(&U)", Qt::CTRL + Qt::Key_Z);
        if ( ret )
        {
            connect(action, SIGNAL(triggered()), &mainEditor, SLOT(undo()));
            action->setEnabled(false);
            menu->addAction(action);
        }

        ret = ret && makeAction(action, mb, "Redo(&R)...", Qt::CTRL + Qt::Key_Y);
        if ( ret )
        {
            connect(action, SIGNAL(triggered()), &mainEditor, SLOT(redo()));
            action->setEnabled(false);
            menu->addAction(action);
        }

        menu->addSeparator();

        ret = ret && makeAction(action, mb, "Cut(&T)", Qt::CTRL + Qt::Key_X);
        if ( ret )
        {
            connect(action, SIGNAL(triggered()), &mainEditor, SLOT(cut()));
            action->setEnabled(false);
            menu->addAction(action);
        }

        ret = ret && makeAction(action, mb, "Copy(&C)", Qt::CTRL + Qt::Key_C);
        if ( ret )
        {
            connect(action, SIGNAL(triggered()), &mainEditor, SLOT(copy()));
            action->setEnabled(false);
            menu->addAction(action);
        }

        ret = ret && makeAction(action, mb, "Paste(&P)", Qt::CTRL + Qt::Key_V);
        if ( ret )
        {
            connect(action, SIGNAL(triggered()), &mainEditor, SLOT(paste()));
            menu->addAction(action);
        }

        ret = ret && makeAction(action, mb, "Delete(&L)", Qt::Key_Delete);
        if ( ret )
        {
            connect(action, SIGNAL(triggered()), this, SLOT(onEditDelete()));
            menu->addAction(action);
        }

        menu->addSeparator();

        ret = ret && makeAction(action, mb,  "Find(&F)...", Qt::CTRL + Qt::Key_F);
        if ( ret )
        {
            connect(action, SIGNAL(triggered()), this, SLOT(onEditFind()));
            menu->addAction(action);
        }

        ret = ret && makeAction(action, mb, "Replace(&R)...", Qt::CTRL + Qt::Key_H);
        if ( ret )
        {
            menu->addAction(action);
        }

        ret = ret && makeAction(action, mb, "Goto(&G)...", Qt::CTRL + Qt::Key_G);
        if ( ret )
        {
            menu->addAction(action);
        }

        menu->addSeparator();

        ret = ret && makeAction(action, mb, "Select All(&A)...", Qt::CTRL + Qt::Key_A);
        if ( ret )
        {
            connect(action, SIGNAL(triggered()), &mainEditor, SLOT(selectAll()));
            menu->addAction(action);
        }
    }

    if ( ret )
    {
        mb->addMenu(menu);
    }
    else
    {
        delete menu;
    }

    return ret;
}

//“格式”菜单
bool MainWindow::initFormatMenu(QMenuBar* mb)
{
    QMenu* menu = new QMenu("Format(&O)", mb);
    bool ret = ( menu != NULL);

    if (ret)
    {
        QAction* action = NULL;

        ret = ret && makeAction(action, mb, );
        if ( ret )
        {
            menu ->addAction(action);
        }

        ret = ret && makeAction(action, mb, );
        if ( ret )
        {
            menu ->addAction(action);
        }
    }

    if ( ret )
    {
        mb->addMenu(menu);
    }
    else
    {
        delete menu;
    }

    return ret;
}

//“查看”菜单
bool MainWindow::initViewMenu(QMenuBar* mb)
{
    QMenu* menu = new QMenu("View(&V)", mb);
    bool ret = ( menu != NULL);

    if (ret)
    {
        QAction* action = NULL;

        ret = ret && makeAction(action, mb, );
        if ( ret )
        {
            menu ->addAction(action);
        }

        ret = ret && makeAction(action, mb, );
        if ( ret )
        {
            menu ->addAction(action);
        }
    }

    if ( ret )
    {
        mb->addMenu(menu);
    }
    else
    {
        delete menu;
    }

    return ret;
}

//“帮助”菜单
bool MainWindow::initHelpMenu(QMenuBar* mb)
{
    QMenu* menu = new QMenu("Help(&H)", mb);
    bool ret = ( menu != NULL);

    if (ret)
    {
        QAction* action = NULL;

        ret = ret && makeAction(action, mb, );
        if ( ret )
        {
            menu ->addAction(action);
        }

        ret = ret && makeAction(action, mb, );
        if ( ret )
        {
            menu ->addAction(action);
        }
    }

    if ( ret )
    {
        mb->addMenu(menu);
    }
    else
    {
        delete menu;
    }

    return ret;
}

//工具栏设置
bool MainWindow::initFileToolItem(QToolBar* tb)
{
    bool ret = true;
    QAction* action = NULL;

    ret = ret && makeAction(action, tb, "New", ":/Res/pic/new.png");
    if ( ret )
    {
        connect(action, SIGNAL(triggered()), this, SLOT(onFileNew()));
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Open", ":/Res/pic/open.png");
    if ( ret )
    {
        connect(action, SIGNAL(triggered()), this, SLOT(onFileOpen()));
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Save", ":/Res/pic/save.png");
    if ( ret )
    {
        connect(action, SIGNAL(triggered()), this, SLOT(onFileSave()));
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Save As", ":/Res/pic/saveas.png");
    if ( ret )
    {
        connect(action, SIGNAL(triggered()), this, SLOT(onFileSaveAs()));
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Print", ":/Res/pic/print.png");
    if ( ret )
    {
        connect(action, SIGNAL(triggered()),this, SLOT(onFilePrint()));
        tb->addAction(action);
    }

    return ret;
}

bool MainWindow::initEditToolItem(QToolBar* tb)
{
    bool ret = true;
    QAction* action = NULL;

    ret = ret && makeAction(action, tb, "Undo", ":/Res/pic/undo.png");
    if ( ret )
    {
        connect(action, SIGNAL(triggered()), &mainEditor, SLOT(undo()));
        action->setEnabled(false);
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Redo", ":/Res/pic/redo.png");
    if ( ret )
    {
        connect(action, SIGNAL(triggered()), &mainEditor, SLOT(redo()));
        action->setEnabled(false);
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Cut", ":/Res/pic/cut.png");
    if ( ret )
    {
        connect(action, SIGNAL(triggered()), &mainEditor, SLOT(cut()));
        action->setEnabled(false);
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Copy", ":/Res/pic/copy.png");
    if ( ret )
    {
        connect(action, SIGNAL(triggered()), &mainEditor, SLOT(copy()));
        action->setEnabled(false);
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Paste", ":/Res/pic/paste.png");
    if ( ret )
    {
        connect(action, SIGNAL(triggered()), &mainEditor, SLOT(paste()));
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Find", ":/Res/pic/find.png");
    if ( ret )
    {
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Replace", ":/Res/pic/replace.png");
    if ( ret )
    {
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Goto", ":/Res/pic/goto.png");
    if ( ret )
    {
        tb->addAction(action);
    }

    return ret;
}

bool MainWindow::initFormatToolItem(QToolBar* tb)
{
    bool ret = true;
    QAction* action = NULL;

    ret = ret && makeAction(action, tb, "Auto Wrap", ":/Res/pic/wrap.png");
    if ( ret )
    {
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Font", ":/Res/pic/font.png");
    if ( ret )
    {
        tb->addAction(action);
    }

    return ret;
}

bool MainWindow::initViewToolItem(QToolBar* tb)
{
    bool ret = true;
    QAction* action = NULL;

    ret = ret && makeAction(action, tb, "Tool Bar", ":/Res/pic/tool.png");
    if ( ret )
    {
        tb->addAction(action);
    }

    ret = ret && makeAction(action, tb, "Status Bar", ":/Res/pic/status.png");
    if ( ret )
    {
        tb->addAction(action);
    }

    return ret;
}

//生成菜单项（第1个参数是菜单项对象，第2个参数为父组件，第3个参数为显示文本，第4个参数为快捷键）
bool MainWindow::makeAction(QAction*& action, QWidget* parent, QString text, int key)
{
    bool ret = true;

    action = new QAction(text, parent); //设置parent

    if(action != NULL)
    {
        action->setShortcut(QKeySequence(key)); //设置快捷键
    }
    else
    {
        ret = false;
    }

    return ret;
}

//生成工具栏中的各按钮
bool MainWindow::makeAction(QAction*& action, QWidget* parent, QString tip, QString icon)
{
    bool ret = true;
    action = new QAction("", parent);

    if( action != NULL )
    {
        action ->setToolTip(tip);
        action->setIcon(QIcon(icon));
    }
    else
    {
       ret = false;
    }

    return ret;
}

MainWindow::~MainWindow()
{

}

//MainWindowSlots.cpp　//与上例相同

4. 小结

（1）QPalette是Qt中标识颜色信息的数据结构

（2）窗口组件内部都拥有QPalette对象

（3）重新设置组件调色板的值能够改变特定区域的颜色

（4）QPalette对象是定制组件外观的重要角色。