Q4之保存窗体状态

在实际的运用过程中，常需要应用程序能保存程序的状态以及用户的设置，如应用程序显示的大小，位置，背景颜色或用户设置的参数等信息，以便在下次运行程序时，能保持上次关闭的状态。

在Qt的使用过程中，我们使用Qsetting来保存程序的状态。使得当用户再次打开时，窗体仍然可以呈现半闭时的状态。

下面我举一个简单的例子加以说明：

贴上代码：

setting.h:

#ifndef SETTINGS_H
#define SETTINGS_H

#include <QDialog>

class QPushButton;
class QLabel;
class QTextEdit;

class Settings : public QDialog
{
    Q_OBJECT
public:
    Settings();
    
    QLabel *label;
    QPushButton *colorBtn;
    QTextEdit *edit;
   
    void readSettings();
    void writeSettings();
    
protected:
    void closeEvent(QCloseEvent *);
    
public slots:
    void slotColor();
};

#endif // SETTINGS_H

setting.cpp:

#include "settings.h"
#include <QtGui>

Settings::Settings()
{
    setWindowTitle("Settings");
    
    label = new QLabel;
    label->setText("Setting Test");    
     
    colorBtn = new QPushButton;
    colorBtn->setText("Select Color");
    
    edit = new QTextEdit;
        
    QGridLayout *layout = new QGridLayout(this);
    layout->addWidget(label,0,0);
    layout->addWidget(colorBtn,0,1);
    layout->addWidget(edit,1,0,1,2);
    
    readSettings();
    
    connect(colorBtn, SIGNAL(clicked()), this, SLOT(slotColor()));
}

void
Settings::slotColor()
{
    QColor color = QColorDialog::getColor (Qt::blue);    
    
    if(color.isValid())
    {
    	QPalette p = label->palette();
	p.setColor(QPalette::Normal,QPalette::WindowText,color);
	label->setPalette(p);
    }
}

void 
Settings::readSettings()
{
    QSettings setting("MyPro","settings");
    setting.beginGroup("Dialog");
    QPoint pos = setting.value("position").toPoint();
    QSize size = setting.value("size").toSize();    
    setting.endGroup();
    
    setting.beginGroup("Content");
    QColor color = setting.value("color").value<QColor>();
    QString text = setting.value("text").toString();
    setting.endGroup();
    
    move(pos);
    resize(size);
    QPalette p = label->palette();
    p.setColor(QPalette::Normal,QPalette::WindowText,color);
    label->setPalette(p);
    edit->setPlainText(text);
}

void
Settings::writeSettings()
{
    QSettings setting("MyPro","settings");
    setting.beginGroup("Dialog");
    setting.setValue("position",pos());
    setting.setValue("size",size());
    setting.endGroup();
    
    setting.beginGroup("Content");
    setting.setValue("color",label->palette().color(QPalette::WindowText));
    setting.setValue("text",edit->toPlainText());
    setting.endGroup();
}

void
Settings::closeEvent(QCloseEvent *e)
{
    writeSettings();
}

settting.pro:

######################################################################
# Automatically generated by qmake (2.01a) ?? ?? 10 23:13:13 2008
######################################################################

TEMPLATE = app
TARGET = 
DEPENDPATH += .
INCLUDEPATH += .

# Input
HEADERS += settings.h
SOURCES += main.cpp settings.cpp

main.cpp:

#include <QApplication>

#include "settings.h"

int main(int argc, char *argv[])
{
    QApplication app(argc,argv);
    Settings *s = new Settings();
    s->show();
    return app.exec();
}

运行效果如下：

点击"select color"按钮，选择一种颜色，

如下：

再次打开，还是显示关闭时的状态。