Qt基本控件及三大布局

https://www.cnblogs.com/lsgxeva/p/7807029.html

来源: http://blog.csdn.net/a2604539133/article/details/73920696

Qt基本模块

一、Qt的三大布局

QHBoxLayout：
1. 水平显示布局，所有在其上面摆放的控件只能水平排列下去；

QVBoxLayout：

垂直显示布局，所有在其上面摆放的控件只能垂直排列下去；

QGridLayout

格子显示布局，可以按照表格的形式显示布局；

二、Qt的控件

label：标签，可以显示文本信息，只读；
pushbutton ：普通按钮；
radiobutton ：单选按钮，多个单选按钮中只能选择一个，但是必须放入groupbox中，类似单选题；
checkbox ：多选复选按钮，可以选择同时选择多个，类似多选题；
lineedit ：单行文本编辑框，可以输入单行文本；
textedit ：多行文本输入框，可以输入显示多行文本和图片；
combobox ：下拉文本输入框，在输入框的最右边有个三角下拉按钮，可以选择输入，也可以手动输入；
textbrower ：多行文本显示框，只读；
groupbox ：可以在里面放入特点的东西，统一管理；
slider ：模拟显示滑动条；
spinbox ：数值显示滑动条；
dateedit ：
timeedit ：
datetimeedit ：
lcdnumber ：

三、Qt的信号槽

在Qt中所有的对象（继承QObject类）都有connect函数，只要有这个函数就能建立信号槽（通过触发某个控件的信号函数，执行槽中相应的函数）；（暂时这样理解，还是有点理解不全面的，之后学习到再来修改）；
在Qt中信号槽中可以使用自带的函数，四个参数；也可以执行自定义的函数，三个参数；具体看下面test4的例子就明白了。

#include <QtWidgets/QApplication>
#include <QtCore/qdebug.h>
#include <QtWidgets/qcompleter.h>
#include <QtWidgets/qlineedit.h>
#include <QtWidgets/qlabel.h> #include <QtWidgets/qcombobox.h> #include <QtWidgets/qcheckbox.h> #include <QtWidgets/qradiobutton.h> #include <QtWidgets/qtextedit.h> #include <QtWidgets/qtextbrowser.h> #include <QtWidgets/qgroupbox.h> #include <QtWidgets/qslider.h> #include <QtWidgets/qspinbox.h> #include <QtWidgets/qdatetimeedit.h> #include <QtWidgets/qtabwidget.h> #include <QtWidgets/qlcdnumber.h> #include <QtGui/qpixmap.h> #include <QtCore/qobject.h> #include <QtWidgets/qboxlayout.h> #include <QtWidgets/qpushbutton.h> #include "MyWidgetEvent.h"

void test() ;

int main(int argc, char *argv[]) {

QApplication a(argc, argv);

test() ;

<span class="hljs-keyword"><span class="hljs-keyword">return</span> a.exec();

}

void test(){

}

void test5ManyKongJian() {

QWidget *nanWidget = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QWidget() ;
QVBoxLayout *nanVLayout = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QVBoxLayout() ;

<span class="hljs-comment"><span class="hljs-comment">/*
**测试label控件
*/</span>
QLabel *label=nullptr ;
nanVLayout-&gt;addWidget( label = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLabel(<span class="hljs-string"><span class="hljs-string">"&lt;a href=www.baidu.com&gt;baidu&lt;/a&gt;"</span>) ) ;
<span class="hljs-comment"><span class="hljs-comment">//QPixmap me("./me.png") ;</span>
<span class="hljs-comment"><span class="hljs-comment">//label-&gt;setPixmap( me ) ;//问题：链接和图片重复了，怎么分开</span>
label-&gt;setWordWrap( <span class="hljs-literal"><span class="hljs-keyword">true</span> ) ;
label-&gt;adjustSize() ;
nanVLayout-&gt;connect( label , &amp;QLabel::linkActivated , []( QString str){
    qDebug()&lt;&lt;str ;
} ) ;
<span class="hljs-comment"><span class="hljs-comment">/*
**测试lineedit控件
*/</span>
QLineEdit *lineEdit ;
nanVLayout-&gt;addWidget( lineEdit = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLineEdit(<span class="hljs-string"><span class="hljs-string">"hello"</span>) ) ;
<span class="hljs-comment"><span class="hljs-comment">/*
**测试button控件
*/</span>
QPushButton *button ;
nanVLayout-&gt;addWidget( button = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QPushButton(<span class="hljs-string"><span class="hljs-string">"???"</span>) ) ;
button-&gt;setStyleSheet(<span class="hljs-string"><span class="hljs-string">"QPushButton {font:bold 16px; color:red;padding:5px}"</span>) ;
nanWidget-&gt;connect( button , &amp;QPushButton::clicked , [](<span class="hljs-keyword">bool flag){
    qDebug()&lt;&lt; <span class="hljs-string"><span class="hljs-string">"button"</span> ;
}) ;
<span class="hljs-comment"><span class="hljs-comment">/*
**测试radiobutton控件
*/</span>
QRadioButton *radioButton ;
nanVLayout-&gt;addWidget( radioButton = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QRadioButton(<span class="hljs-string"><span class="hljs-string">"qradiobutton"</span>) ) ;
radioButton-&gt;setStyleSheet(<span class="hljs-string"><span class="hljs-string">"QRadioButton {font:bold  16px;color:blue;padding:5px}"</span>) ;
radioButton-&gt;connect( radioButton , &amp;QRadioButton::clicked , [](<span class="hljs-keyword">bool flag){
    qDebug()&lt;&lt; flag ;
}) ;
<span class="hljs-comment"><span class="hljs-comment">/*
**测试ckeckbox控件
*/</span>
QCheckBox *check ;
nanVLayout-&gt;addWidget( check = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QCheckBox(<span class="hljs-string"><span class="hljs-string">"chekcbox"</span>) ) ;
<span class="hljs-comment"><span class="hljs-comment">/*
**测试combobox控件
*/</span>
QComboBox *combobox ;
nanVLayout-&gt;addWidget( combobox = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QComboBox() ) ;
combobox-&gt;addItem(<span class="hljs-string"><span class="hljs-string">"select item1"</span>) ;
combobox-&gt;addItem(<span class="hljs-string"><span class="hljs-string">"select item2"</span>) ;
combobox-&gt;addItem(<span class="hljs-string"><span class="hljs-string">"...  ..."</span>) ;
combobox-&gt;setEditable(<span class="hljs-literal"><span class="hljs-keyword">true</span>) ;
lineEdit-&gt;setText(<span class="hljs-string"><span class="hljs-string">"start"</span>) ;
combobox-&gt;connect( combobox , SIGNAL(activated(<span class="hljs-keyword"><span class="hljs-keyword">const</span> QString &amp;)) , lineEdit , SLOT(setText(<span class="hljs-keyword"><span class="hljs-keyword">const</span> QString &amp;)) ) ;<span class="hljs-comment"><span class="hljs-comment">//这里的下标要跟着显示</span>
combobox-&gt;setCompleter( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QCompleter(combobox-&gt;model()) ) ;
<span class="hljs-comment"><span class="hljs-comment">/*
**测试textedit
*/</span>
QTextEdit *textEdit ;
nanVLayout-&gt;addWidget( textEdit = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QTextEdit(<span class="hljs-string"><span class="hljs-string">"textedit"</span>) ) ;
textEdit-&gt;setText(<span class="hljs-string"><span class="hljs-string">"&lt;table border=2&gt; "</span>
                <span class="hljs-string"><span class="hljs-string">"&lt;tr&gt;&lt;td&gt;good&lt;/td&gt;&lt;td&gt;good&lt;/td&gt;&lt;td&gt;good&lt;/td&gt;&lt;/tr&gt;"</span>
                <span class="hljs-string"><span class="hljs-string">"&lt;tr&gt;&lt;td&gt;nice&lt;/td&gt;&lt;td&gt;nice&lt;/td&gt;&lt;td&gt;nice&lt;/td&gt;&lt;/tr&gt;"</span>
                <span class="hljs-string"><span class="hljs-string">"&lt;/table&gt;"</span>
                <span class="hljs-string"><span class="hljs-string">"&lt;img src=./me.png&gt;&lt;/img&gt;"</span>) ;
textEdit-&gt;connect( textEdit , &amp;QTextEdit::textChanged,[&amp;](){
    <span class="hljs-comment"><span class="hljs-comment">//问题：textEdit-&gt;toPlainText() ;怎么才能获取到textEdit的实体，this-&gt;sender()</span>
    <span class="hljs-comment"><span class="hljs-comment">//QTextEdit _edit = (QTextEdit *)QObject::sender();</span>
    qDebug()&lt;&lt;textEdit-&gt;toPlainText() ;
}) ;
textEdit-&gt;setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded) ;
textEdit-&gt;setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOn) ;
<span class="hljs-comment"><span class="hljs-comment">/*
**测试groupbox控件
*/</span>
QGroupBox *groupBox ;
nanVLayout-&gt;addWidget( groupBox = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QGroupBox(<span class="hljs-string"><span class="hljs-string">"groupbox"</span>) ) ;
QHBoxLayout *hLayout ;
groupBox-&gt;setLayout( hLayout = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QHBoxLayout() ) ;
hLayout-&gt;addWidget( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QRadioButton(<span class="hljs-string"><span class="hljs-string">"boy"</span>) ) ;
hLayout-&gt;addWidget( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QRadioButton(<span class="hljs-string"><span class="hljs-string">"girl"</span>) ) ;
<span class="hljs-comment"><span class="hljs-comment">/*
**测试模拟显示条slider
*/</span>
QSlider *slider ;
nanVLayout-&gt;addWidget( slider = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QSlider() ) ;
slider-&gt;setMinimum( <span class="hljs-number">-</span><span class="hljs-number"><span class="hljs-number">100</span> ) ;
slider-&gt;setMaximum( <span class="hljs-number"><span class="hljs-number">100</span> ) ;
<span class="hljs-comment"><span class="hljs-comment">/*
**测试数字显示条
*/</span>
QSpinBox *spinBox ;
nanVLayout-&gt;addWidget( spinBox = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QSpinBox() ) ;
spinBox-&gt;setMinimum( <span class="hljs-number">-</span><span class="hljs-number"><span class="hljs-number">100</span> ) ;
spinBox-&gt;setMaximum( <span class="hljs-number"><span class="hljs-number">100</span> ) ;
slider-&gt;connect( slider , SIGNAL(valueChanged(<span class="hljs-keyword">int)) , spinBox , SLOT(setValue(<span class="hljs-keyword">int)) ) ;
spinBox-&gt;connect( spinBox , SIGNAL(valueChanged(<span class="hljs-keyword">int)) , slider , SLOT(setValue(<span class="hljs-keyword">int)) ) ;
<span class="hljs-comment"><span class="hljs-comment">/*
**测试时间设置
*/</span>
nanVLayout-&gt;addWidget( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QDateTimeEdit() ) ;
<span class="hljs-comment"><span class="hljs-comment">/*
**测试显示时间，只读
*/</span>
QLCDNumber *number ;
nanVLayout-&gt;addWidget( number = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLCDNumber() ) ;
number-&gt;display(<span class="hljs-string"><span class="hljs-string">"1314"</span>) ;
number-&gt;setMode(QLCDNumber::Hex) ;
number-&gt;setSegmentStyle(QLCDNumber::Filled) ;

nanWidget-&gt;setLayout( nanVLayout ) ;
nanWidget-&gt;setWindowTitle(<span class="hljs-string"><span class="hljs-string">"control"</span>) ;
nanWidget-&gt;show() ;

}

void test4GridAndHBox() {

QWidget *nanWidget = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QWidget() ;
QGridLayout *nanGridLayout = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QGridLayout() ;
QHBoxLayout *nanHBoxLayout = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QHBoxLayout() ;

nanGridLayout-&gt;addWidget( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLabel(<span class="hljs-string"><span class="hljs-string">"Username"</span>) , <span class="hljs-number"><span class="hljs-number">1</span> , <span class="hljs-number"><span class="hljs-number">1</span> ) ;
nanGridLayout-&gt;addWidget( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLineEdit() , <span class="hljs-number"><span class="hljs-number">1</span> , <span class="hljs-number"><span class="hljs-number">2</span> ) ;
nanGridLayout-&gt;addWidget( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLabel(<span class="hljs-string"><span class="hljs-string">"Username"</span>) , <span class="hljs-number"><span class="hljs-number">2</span> , <span class="hljs-number"><span class="hljs-number">1</span> ) ;
nanGridLayout-&gt;addWidget( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLineEdit() , <span class="hljs-number"><span class="hljs-number">2</span> , <span class="hljs-number"><span class="hljs-number">2</span> ) ;
nanGridLayout-&gt;addLayout( nanHBoxLayout , <span class="hljs-number"><span class="hljs-number">3</span> , <span class="hljs-number"><span class="hljs-number">2</span> ) ;

nanHBoxLayout-&gt;addStretch(<span class="hljs-number"><span class="hljs-number">1</span>) ;
nanHBoxLayout-&gt;addWidget( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QPushButton(<span class="hljs-string"><span class="hljs-string">"Login"</span>) , <span class="hljs-number"><span class="hljs-number">1</span> ) ;

nanWidget-&gt;setLayout( nanGridLayout ) ;
nanWidget-&gt;show() ;

}

void test3GridLayout() {

QWidget *nanWidget = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QWidget() ;
QGridLayout *nanLayout = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QGridLayout() ;
QPushButton *nanButton = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QPushButton() ;
QLineEdit *nanLineEdit = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLineEdit() ;

nanLayout-&gt;addWidget( nanLineEdit , <span class="hljs-number"><span class="hljs-number">1</span> , <span class="hljs-number"><span class="hljs-number">1</span> , <span class="hljs-number"><span class="hljs-number">1</span> , <span class="hljs-number"><span class="hljs-number">2</span> ) ;
nanLayout-&gt;addWidget( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QPushButton , <span class="hljs-number"><span class="hljs-number">1</span>, <span class="hljs-number"><span class="hljs-number">3</span> ) ;
nanLayout-&gt;addWidget( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLineEdit , <span class="hljs-number"><span class="hljs-number">2</span>, <span class="hljs-number"><span class="hljs-number">1</span> , <span class="hljs-number"><span class="hljs-number">2</span> , <span class="hljs-number"><span class="hljs-number">1</span>  ) ; 
nanLayout-&gt;addWidget( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QPushButton , <span class="hljs-number"><span class="hljs-number">2</span>, <span class="hljs-number"><span class="hljs-number">2</span> ) ;
nanLayout-&gt;addWidget( <span class="hljs-keyword"><span class="hljs-keyword">new</span> QPushButton , <span class="hljs-number"><span class="hljs-number">2</span>, <span class="hljs-number"><span class="hljs-number">3</span> ) ;
nanLayout-&gt;addWidget( nanButton , <span class="hljs-number"><span class="hljs-number">3</span> , <span class="hljs-number"><span class="hljs-number">3</span> ) ;
nanLayout-&gt;setColumnStretch( <span class="hljs-number"><span class="hljs-number">1</span> , <span class="hljs-number"><span class="hljs-number">1</span> ) ;
nanLayout-&gt;setColumnStretch( <span class="hljs-number"><span class="hljs-number">2</span> , <span class="hljs-number"><span class="hljs-number">1</span> ) ;<span class="hljs-comment"><span class="hljs-comment">/*设置每列的比重*/</span>
nanLayout-&gt;setColumnStretch( <span class="hljs-number"><span class="hljs-number">3</span> , <span class="hljs-number"><span class="hljs-number">1</span> ) ;

nanWidget-&gt;setLayout( nanLayout ) ;
nanWidget-&gt;show() ;

}

void test2HBoxLayout() {

QWidget *nanQWidget = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QWidget() ;

QLineEdit *nanQLineEdit = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLineEdit() ;

QHBoxLayout *nanHLayout = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QHBoxLayout() ;
nanHLayout-&gt;addWidget( nanQLineEdit , <span class="hljs-number"><span class="hljs-number">1</span> ) ;
<span class="hljs-comment"><span class="hljs-comment">//添加，两个控件之间的距离addspaceing，两个控件在layout中的比重addstretch</span>

nanQWidget-&gt;setLayout( nanHLayout ) ;
nanQWidget-&gt;show() ;

}

void test1(){

QWidget *w  = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QWidget ;
QVBoxLayout *vLayout = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QVBoxLayout( ) ;
QPushButton *nanButton ;
QLineEdit *nanLineEdit ;
QLabel *nanLabel ;
QString content(<span class="hljs-string"><span class="hljs-string">"null"</span>) ;
QCompleter nanQCompleter( QStringList()&lt;&lt;<span class="hljs-string"><span class="hljs-string">"nich"</span>&lt;&lt;<span class="hljs-string"><span class="hljs-string">"chen"</span>&lt;&lt;<span class="hljs-string"><span class="hljs-string">"good"</span>) ;

vLayout-&gt;addWidget( nanLineEdit = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLineEdit()  ) ;
vLayout-&gt;addWidget( nanButton = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QPushButton(<span class="hljs-string"><span class="hljs-string">"right"</span>) ) ;
nanQCompleter.setFilterMode( Qt::MatchFlag::MatchContains ) ;
nanLineEdit-&gt;setCompleter( &amp;nanQCompleter ) ;
nanLineEdit-&gt;setPlaceholderText( <span class="hljs-string"><span class="hljs-string">"Please input your name"</span> ) ;
vLayout-&gt;addWidget(  nanLabel = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLabel() ) ;
nanLabel-&gt;setText( content ) ;
w-&gt;connect( nanButton , &amp;QPushButton::clicked , [&amp;](){
    nanLabel-&gt;setText( nanLineEdit-&gt;text() ) ;
} ) ;

w-&gt;setLayout( vLayout) ;
w-&gt;show() ;

}

一、dialog、widget、mainwindow的区别

1)、dialog有exec函数，如果是dialog窗口，后边的窗口时不可选的；
2)、widget和dialog都有show函数，如果通过这个函数显示这两种类型的窗口，则两个窗口都是可选的；
3)、widget主要是在上面放置布局和控件；
4)、mainwindow可以显示菜单，工具栏，状态栏、托盘等功能。

二、dialog窗口

这个dialog窗口只是为了给人们提供更好的可视化操作，但是对于程序员而言，这个操作并不是立刻执行的；而是当在窗口选择关闭后，才将选择的结果返回给后台，后台才可以根据选择的结果进行相应的操作。

#include "mydialog.h"

mydialog::mydialog(QDialog *parent):QDialog(parent) {

QPushButton *button = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QPushButton( <span class="hljs-string"><span class="hljs-string">"button"</span> , <span class="hljs-keyword"><span class="hljs-keyword">this</span> ) ;
connect( button , SIGNAL(clicked()) , <span class="hljs-keyword"><span class="hljs-keyword">this</span> , SLOT(slotButtonClick()) ) ;

}

void mydialog::slotButtonClick() {

#if 0
/dialog和widget的区别，exec和show的区别而已/
QDialog *dlg = new QDialog ;
QPushButton *button = new QPushButton(“close” , dlg ) ;
connect( button , SIGNAL(clicked()) , dlg , SLOT(reject()) ) ;
int ret = dlg->exec( ) ;
//通过exec显示出来的窗口称为，模块对话框
// 在模块对话框中，exec有自己的消息循环，并且把app的消息循环接管了
// 如果Dialog是通过exec来显示，那么可以通过accept或者reject来关闭窗口
// 如果Dialog是通过show来显示，那么可以通过close来关闭窗口，这个和QWidget一样的

<span class="hljs-comment"><span class="hljs-comment">// 有许多特殊的dailog：文件选择，MessageBox，颜色选择，字体选择，打印预览，打印</span>
<span class="hljs-keyword"><span class="hljs-keyword">if</span>( ret == QDialog::Accepted ) 
    qDebug()&lt;&lt;<span class="hljs-string"><span class="hljs-string">"accepted"</span> ;
<span class="hljs-keyword"><span class="hljs-keyword">else</span> <span class="hljs-keyword"><span class="hljs-keyword">if</span>( ret== QDialog::Rejected ) 
    qDebug()&lt;&lt;<span class="hljs-string"><span class="hljs-string">"rejected"</span> ;

#endif
#if 0
/文件选择：这个窗口可以选择保存文件的名称，然后将路径+名称返回，我们就可以根据返回路径名来保存文件。/
QString strFilename = QFileDialog::getSaveFileName(NULL,
“Select file for save”,
_strDir,
“pic file (*.png .jpg)");
#endif
#if 0
/文件选择：选择要打开的文件名（绝对路劲）；我们就可以根据这个文件路径来打开相应的文件/
QString strFilename = QFileDialog::getOpenFileName(NULL,
“Select file for open”,
_strDir,
"pic file (.png *.jpg)”);
#endif
#if 0
QString strFilename = QFileDialog::getExistingDirectory();

<span class="hljs-keyword"><span class="hljs-keyword">if</span>(strFilename.isEmpty())
{
    qDebug() &lt;&lt; <span class="hljs-string"><span class="hljs-string">"select none"</span>;
    <span class="hljs-keyword"><span class="hljs-keyword">return</span>;
}

qDebug() &lt;&lt; strFilename;
<span class="hljs-function">QFileInfo <span class="hljs-title">fileInfo</span>(<span class="hljs-params">strFilename</span>)</span>;
_strDir = fileInfo.filePath();
qDebug() &lt;&lt; _strDir;

#endif
//do something for io … …
//上面的选择将绝对路径名都给拿下来了，如果要进行保存，不是很容易吗！
QPixmap pixmap(this->size()) ;
QPainter painter(&pixmap) ;
this->render( &painter ) ;
pixmap.save(strFilename) ;
#if 0
/颜色选择对话框：可以选择相应的颜色；然后将选择的颜色返回，这样我们就可以操作了/
QColorDialog colorDia ;
colorDia.exec() ;
QColor c = colorDia.selectedColor() ;
#endif
#if 0
/字体选择对话框：可以选择字体；然后将选择的字体信息返回，我们同样可以用这些信息来设置相应的值/
QFontDialog fontDia ;
fontDia.exec() ;
QFont font = fontDia.selectedFont() ;
#endif
#if 0
/这个也是弹窗对话框，不过只是简单的选择以下枚举中的值，可以尝试下效果/
int ret = QMessageBox::question(this, “???”, “realy do …”,
QMessageBox::Yes| QMessageBox::No|
QMessageBox::YesAll| QMessageBox::NoAll);
if(ret == QMessageBox::Yes)
{
qDebug() << “user select yes”;
}
if(ret == QMessageBox::No)
{
qDebug() << “user select no”;
}
#endif
}

void mydialog::paintEvent( QPaintEvent *ev ) {
}

mydialog::~mydialog(void) { }

前面已经介绍过很多继承这个窗口的控件了，这里就不再累述。

四、mainWindow窗口

这个也是给人们提供更好的可视化操作；
一个正常window软件呈现给客户的可视化界面；
包括：menu菜单、tool工具栏、status状态栏、电脑显示屏右下脚的托盘等。

#include "MyWindow.h"

MyWindow::MyWindow(QMainWindow *parent):QMainWindow( parent ) {

<span class="hljs-comment"><span class="hljs-comment">/*menuBar菜单栏，菜单menu*/</span>
QMenuBar  *menuBar = <span class="hljs-keyword"><span class="hljs-keyword">this</span>-&gt;menuBar() ;
_menu = menuBar-&gt;addMenu( <span class="hljs-string"><span class="hljs-string">"&amp;File"</span> ) ;
QMenu *edit = menuBar-&gt;addMenu( <span class="hljs-string"><span class="hljs-string">"&amp;Edit"</span> ) ;

<span class="hljs-comment"><span class="hljs-comment">/*menu菜单中的选项action*/</span>
QAction *openAction = _menu-&gt;addAction( <span class="hljs-string"><span class="hljs-string">"&amp;Open"</span>
    , <span class="hljs-keyword"><span class="hljs-keyword">this</span> , SLOT(slotOpen()) , QKeySequence::Open  ) ;
QAction *saveAction = _menu-&gt;addAction( <span class="hljs-string"><span class="hljs-string">"&amp;Save"</span>
    , <span class="hljs-keyword"><span class="hljs-keyword">this</span> , SLOT(slotOpen()) , QKeySequence::Save  ) ;
_menu-&gt;addSeparator() ;<span class="hljs-comment"><span class="hljs-comment">//添加分界线</span>
QAction *closeAction = _menu-&gt;addAction( <span class="hljs-string"><span class="hljs-string">"&amp;Exit"</span>
    , <span class="hljs-keyword"><span class="hljs-keyword">this</span> , SLOT(close()) , QKeySequence::Close  ) ;

<span class="hljs-comment"><span class="hljs-comment">/*toolBar工具栏*/</span>
QToolBar *toolBar = <span class="hljs-keyword"><span class="hljs-keyword">this</span>-&gt;addToolBar( <span class="hljs-string"><span class="hljs-string">"mimi"</span> ) ;
toolBar-&gt;addAction( openAction ) ;
toolBar-&gt;addAction( saveAction ) ;
toolBar-&gt;addAction( closeAction ) ;
<span class="hljs-comment"><span class="hljs-comment">/*statusBar状态栏*/</span>
QStatusBar *statusBar = <span class="hljs-keyword"><span class="hljs-keyword">this</span>-&gt;statusBar() ;
QLabel *label ;
statusBar-&gt;addWidget( label = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QLabel(<span class="hljs-string"><span class="hljs-string">"Ok"</span>) ) ;
label-&gt;setText( <span class="hljs-string"><span class="hljs-string">"&lt;font color=blue&gt;XXXXX... ...&lt;/font&gt;"</span> ) ;
<span class="hljs-comment"><span class="hljs-comment">/*上面的三种栏介绍完之后，剩下的窗口区域就是CentralWidget
**如果将widget直接add到mainwindow这个窗口的话，
**toolbar是会跟添加进来的widget重叠的*/</span>
MyView *view = <span class="hljs-keyword"><span class="hljs-keyword">new</span> MyView ;
<span class="hljs-keyword"><span class="hljs-keyword">this</span>-&gt;setCentralWidget( view ) ;
<span class="hljs-comment"><span class="hljs-comment">/*最后就是window系统右下脚的托盘：system tray icon*/</span>
QSystemTrayIcon *icon = <span class="hljs-keyword"><span class="hljs-keyword">new</span> QSystemTrayIcon ;
icon-&gt;setIcon( QIcon(<span class="hljs-string"><span class="hljs-string">"./1.png"</span>) ) ;<span class="hljs-comment"><span class="hljs-comment">//图标</span>
icon-&gt;setToolTip( <span class="hljs-string"><span class="hljs-string">"luck dog"</span> ) ;<span class="hljs-comment"><span class="hljs-comment">//鼠标滑过提示文字</span>
icon-&gt;show() ;<span class="hljs-comment"><span class="hljs-comment">//展示在右下角</span>
icon-&gt;setContextMenu( _menu ) ;<span class="hljs-comment"><span class="hljs-comment">//右击出现的菜单</span>
<span class="hljs-keyword"><span class="hljs-keyword">this</span>-&gt;connect( icon , SIGNAL( slotActivated(QSystemTrayIcon::ActivationReason) ) 
    , <span class="hljs-keyword"><span class="hljs-keyword">this</span> , SLOT(slotActivated(QSystemTrayIcon::QSystemTrayIcon::ActivationReason)) ) ;
<span class="hljs-keyword"><span class="hljs-keyword">this</span>-&gt;installEventFilter(<span class="hljs-keyword"><span class="hljs-keyword">this</span>);

}

void MyWindow::slotActivated(QSystemTrayIcon::ActivationReason reason){

<span class="hljs-comment"><span class="hljs-comment">/*这个没成功*/</span>
<span class="hljs-keyword"><span class="hljs-keyword">if</span>( reason==QSystemTrayIcon::Trigger ) {
    <span class="hljs-keyword"><span class="hljs-keyword">if</span>( <span class="hljs-keyword"><span class="hljs-keyword">this</span>-&gt;isHidden() ) 
        <span class="hljs-keyword"><span class="hljs-keyword">this</span>-&gt;show() ;
    <span class="hljs-keyword"><span class="hljs-keyword">else</span>
        <span class="hljs-keyword"><span class="hljs-keyword">this</span>-&gt;hide() ;
}

}

bool MyWindow::eventFilter(QObject *o, QEvent e)
{
/实现什么功能呢？/
if(o == (QObject)this && e->type() == QEvent::Close)
{
return true;
}

<span class="hljs-keyword"><span class="hljs-keyword">return</span> QMainWindow::eventFilter(o, e);

}

void MyWindow::slotOpen() {

QString fileName = QFileDialog::getOpenFileName() ;
qDebug()&lt;&lt;fileName ;
<span class="hljs-comment"><span class="hljs-comment">/*将打开的文件中的内容显示在窗口上... ...*/</span>

}
bool MyWindow::event(QEvent *ev)
{
qDebug() << ev;
if(ev->type() == QEvent::Close) {
return false;
}
/怎么弄才能实现窗口关闭，托盘还在？/
return QMainWindow::event(ev);
}

void MyWindow::paintEvent( QPaintEvent * ) {

<span class="hljs-function">QPainter <span class="hljs-title">painter</span>(</span><span class="hljs-keyword"><span class="hljs-function"><span class="hljs-params"><span class="hljs-keyword">this</span></span>) </span>;
painter.drawPixmap( QPoint(<span class="hljs-number"><span class="hljs-number">0</span>,<span class="hljs-number"><span class="hljs-number">0</span>) , QPixmap(<span class="hljs-string"><span class="hljs-string">"./1.png"</span>) ) ;

}

void MyWindow::mousePressEvent( QMouseEvent *ev ) {

<span class="hljs-keyword"><span class="hljs-keyword">if</span>( ev-&gt;button() == Qt::RightButton ) {
    _menu-&gt;exec( QCursor::pos() ) ;
}

}

MyWindow::~MyWindow(void) { }

一、qDebug()函数

qDebug（）函数可以直接输出调试错误信息，方便程序员调试信息，查找错误；
例子：qDebug()<<"error"<<endl;

二、QDebug类

这个函数可以收集错误信息，通过QTextStream这个类（之前在写文件的时候，用过这个类，查看了下函数的作用，果真和自己想的一样）；
QTextStream类，指定一个Qfile*或是QString*作为参数，重载了<<操作符，将对象（QTextStream<<。。）收集到的数据都保存入，相应的参数（这个参数由构造函数决定）中，方便统一管理。例如：在构造时如果指定了文件指针，就直接保存如文件；在构造时如果指定了string，就直接保存如string中… …
总结：这个错误类不是用来输出信息的（当然简介使用错误函数也是可以输出信息），更重要的是用来收集错误信息，方便统一管理，保存，查看的。

    QString *str ;
    QDebug q( str = new QString("object") ) ;
    q<<"nice";
    qDebug()<< *str ;

写写代码想想她

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