Qt初步的信号与槽
首先瞎说一些废话：
因为Qt的环境很恶心，我从官网上下载花了16个小时还是只完成4%，所以，是不是资源有问题。
接着对于vs2008和vs2010，至今没有看到Qt对于哪个支持的比较好，我的2008和2010对代码辨认轮番好使，真心不知道有什么地方出现问题。
代码提示安装了一个VAssisX的VC插件，包含Qt路径中的include之后，于是，你可以看见犹如Eclipse的强大代码提示功能了。
Qt的消息响应，其实就总结与消息与槽的映射：
connect(sender，SIGNAL(signal),reciver,SLOT(slot));
前两个参数分别是发出消息的对象和消息函数；后面两个参数分别是接受者的对象和响应函数；
例如：
connect(lineEdit,SIGNAL(textChanged(const QString &)),this,SLOT(enableFindButton(const QString &)));
lineEdit的文字被修改的时候，触发了textChanged()函数，之后窗口类接受消息，通过槽enableFindButton()实现消息响应；
下面是完整的FindDialog的实现：
//find.h
#ifndef FINDDIALOG_H
#define FINDDIALOG_H
#include <QDialog>
#include <QtGui/QLabel>
#include <QtGui/QPushButton>
#include <QtGui/QCheckBox>
#include <QtGui/QLineEdit>
class QCheckBox;
class QLabel;
class QLineEdit;
class QPushButton;
class FindDialog :public QDialog
{
Q_OBJECT
public:
FindDialog(QWidget* parent = 0);
signals:
void findNext(QString &str,Qt::CaseSensitivity cs);
void findPrevious(QString &str,Qt::CaseSensitivity cs);
private
slots:
void findChecked();
void enableFindButton(const QString &text);
private:
QLabel *label;
QLineEdit *lineEdit;
QCheckBox *caseCheckBox;
QCheckBox *backwardCheckBox;
QPushButton *findButton;
QPushButton *closeButton;
};
#endif
//find.cpp
#include "find.h"
#include <QtGui/QtGui>
FindDialog::FindDialog(QWidget* parent):QDialog(parent)
{
//create label add lineEdit into
label = new QLabel(tr("Find &what:"));
lineEdit = new QLineEdit;
label->setBuddy(lineEdit);
//single choose check
caseCheckBox = new QCheckBox(tr("Mach &case"));
backwardCheckBox = new QCheckBox(tr("Search &backward"));
//button initialization
findButton = new QPushButton(tr("&Find"));
findButton->setDefault(true);
findButton->setEnabled(false);
closeButton = new QPushButton(tr("Close"));
//signal and slot
//if the textChaged light the find_button
connect(lineEdit,SIGNAL(textChanged(const QString &)),this,SLOT(enableFindButton(const QString &)));
//if findButton be clicked slot findClick()
connect(findButton,SIGNAL(clicked()),this,SLOT(fingClicked()));
//if closeButton be clicked close the dialog
connect(closeButton,SIGNAL(clicked()),this,SLOT(close()));
//Layout
QHBoxLayout *topleftLayout = new QHBoxLayout;
topleftLayout->addWidget(label);
topleftLayout->addWidget(lineEdit);
QVBoxLayout *leftLayout = new QVBoxLayout;
leftLayout->addLayout(topleftLayout);
leftLayout->addWidget(caseCheckBox);
leftLayout->addWidget(backwardCheckBox);
QVBoxLayout *rightLayout = new QVBoxLayout;
rightLayout->addWidget(findButton);
rightLayout->addWidget(closeButton);
rightLayout->addStretch();
QHBoxLayout* mainLayout = new QHBoxLayout;
mainLayout->addLayout(leftLayout);
mainLayout->addLayout(rightLayout);
setLayout(mainLayout);
setWindowTitle(tr("Find"));
setFixedHeight(sizeHint().height());
}
void FindDialog::findChecked()
{
QString text = lineEdit->text();
Qt::CaseSensitivity cs = caseCheckBox->isChecked()?Qt::CaseSensitive:Qt::CaseInsensitive;
if(backwardCheckBox->isChecked()){
emit findPrevious(text,cs);
}else{
emit findNext(text,cs);
}
}
void FindDialog::enableFindButton(const QString &text){
findButton->setEnabled(!text.isEmpty());
}
//main.cpp
#include "qtry.h"
#include <QtGui/QApplication>
#include "find.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
FindDialog* dialog = new FindDialog();
dialog->show();
return a.exec();
}
再如：
Qt实现简易时钟，painter实现;
connect(timer,SIGNAL(timeout()),this,SLOT(update()));
当timer发生timerout()消息时，窗口获取消息，通过update()实现。
另外，还知道了painter的setbackground好像不兼容与Qt4，不知道应该怎么解决。
//clock.h
#include <QtGui/QWidget>
class clock:public QWidget
{
Q_OBJECT
public:
clock(QWidget *parent = 0);
protected:
void paintEvent(QPaintEvent *event);
};
//clock.cpp
#include <QtGui/QtGui>
#include "Clock.h"
clock::clock(QWidget* parent):QWidget(parent)
{
//new clock class
//new time now.
QTimer* timer = new QTimer(this);
//create signal and slot
connect(timer,SIGNAL(timeout()),this,SLOT(update()));
//time start between 100ms
timer->start(100);
//set window title
setWindowTitle("Clock");
//resize the window
resize(200,200);
}
void clock::paintEvent(QPaintEvent *)
{
//time hand set point
static const QPoint hourhand[3]={
QPoint(7,8),
QPoint(-7,8),
QPoint(0,40)
};
static const QPoint minutehand[3]={
QPoint(7,8),
QPoint(-7,8),
QPoint(0,-70)
};
static const QPoint secondhand[3]={
QPoint(7,8),
QPoint(-7,8),
QPoint(0,-70)
};
//set color for handColor
QColor hourColor(127,0,127);
QColor minuteColor(0,127,127);
QColor secondColor(127,127,0);
int side = qMin(width(),height());
//currentTime for time
QTime time = QTime::currentTime();
//create painter
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing);
painter.translate(width()/2,height()/2);
painter.scale(side/200.00,side/200.00);
painter.setPen(Qt::NoPen);
painter.setBrush(hourColor);
painter.save();
painter.rotate(30.0*(time.hour()+time.minute()/60.0));
painter.drawConvexPolygon(hourhand,3);
painter.restore();
painter.setPen(Qt::NoPen);
painter.setBrush(minuteColor);
painter.save();
painter.rotate(6.0*(time.minute()+time.second()/60.0));
painter.drawConvexPolygon(minutehand,3);
painter.restore();
painter.rotate(6.0*time.second());
painter.drawConvexPolygon(secondhand,3);
//painter.restore();
const QColor aaacolor(122,122,122);
//painter.setBackgroundColor(aaacolor);
//this->backgroundColor(122,122,122);
}
//main.cpp
#include "tryqt.h"
#include <QtGui/QApplication>
#include <QtGui/QSlider>
#include <QtGui/QWidget>
#include <QtGui/QSpinBox>
#include <QtGui/QHBoxLayout>
#include <QtGui/QPushButton>
#include "Clock.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
clock c;
c.show();
return a.exec();
}
代码内部有我很水的英文注释，代码是直接从VS2010中沾过来的，运行没问题。
明天开始学习QtDesigner。加油吧孩子。为了很多。
