Qt学习（五）自定义对话框，多窗口开发---添加设计师类， MDI多窗口开发

一 对话框

• 实现功能：打开文件，选择目录，保存文件，选择颜色，选择字体，输入信息，
  消息提示框
  
  

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget *parent = nullptr);~MainWindow();private slots:void on_pushButtonSelectOneFile_clicked();void on_pushButtonSelectMultiFile_clicked();void on_pushButtonSelectRoot_clicked();void on_pushButtonSaveFile_clicked();void on_pushButtonColor_clicked();void on_pushButtonFont_clicked();void on_pushButtonInputString_clicked();void on_pushButtonInputInt_clicked();void on_pushButtonInputFloat_clicked();void on_pushButtonSelectItem_clicked();void on_pushButtonQuestion_clicked();void on_pushButtonMessage_clicked();void on_pushButtonWarning_clicked();void on_pushButtonWarningSerious_clicked();void on_pushButtonVersion_clicked();void on_pushButtonVersionQT_clicked();void on_pushButton_clicked();private:Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QFileDialog>
#include <QTextStream>
#include <QColorDialog>
#include <QFontDialog>
#include <QInputDialog>
#include <QMessageBox>MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);}MainWindow::~MainWindow()
{delete ui;
}void MainWindow::on_pushButtonSelectOneFile_clicked()
{QString filename = QFileDialog::getOpenFileName(this,"选择一个文件",QDir::currentPath(),"文本文件(*txt);;C/C++文件(*.h *.c *.cpp);; 图片文件(*.jpg *.png *.gif);;所有文件(*.*)");if(!filename.isEmpty()){ui->plainTextEdit->appendPlainText(filename);}
}void MainWindow::on_pushButtonSelectMultiFile_clicked()
{QStringList filename = QFileDialog::getOpenFileNames(this,"选择多个文件",QDir::currentPath(),"文本文件(*txt);;C/C++文件(*.h *.c *.cpp);; 图片文件(*.jpg *.png *.gif);;所有文件(*.*)");if(filename.count() > 0){for(int i = 0; i < filename.count() ; i++)ui->plainTextEdit->appendPlainText(filename[i]);}
}void MainWindow::on_pushButtonSelectRoot_clicked()
{QString filename = QFileDialog::getExistingDirectory(this,"选择一个目录",QDir::currentPath(),QFileDialog::ShowDirsOnly);if(!filename.isEmpty()){ui->plainTextEdit->appendPlainText(filename);}
}void MainWindow::on_pushButtonSaveFile_clicked()
{QString filename = QFileDialog::getSaveFileName(this,"保存文件",QDir::currentPath(),"文本文件(*txt);;C/C++文件(*.h *.c *.cpp);; 图片文件(*.jpg *.png *.gif);;所有文件(*.*)");if(!filename.isEmpty()){//把文本编辑器的内容保存到文本QFile qfile(filename);if(! qfile.open(QIODevice::WriteOnly | QIODevice::Text | QIODevice::Truncate)){return;}QTextStream stream(&qfile);stream << ui->plainTextEdit->toPlainText();qfile.close();ui->plainTextEdit->appendPlainText("已保存到:" + filename);}
}void MainWindow::on_pushButtonColor_clicked()
{QPalette pal = ui->plainTextEdit->palette(); //获取文本框的调色板QColor textColor = pal.color(QPalette::Text);  //获取文本框里面的本文的颜色//调用颜色对话框QColor color = QColorDialog::getColor(textColor,  //初始颜色this,       //父窗口"选择文本颜色");  //显示信息if(color.isValid()){pal.setColor(QPalette::Text,color);ui->plainTextEdit->setPalette(pal);}
}void MainWindow::on_pushButtonFont_clicked()
{QFont currentFont = ui->plainTextEdit->font();bool ok = false;//调用字体选择对话框QFont font = QFontDialog::getFont(&ok,currentFont);if(ok){ui->plainTextEdit->setFont(font);}
}void MainWindow::on_pushButtonInputString_clicked()
{bool ok = false;//QLineEdit::Normal:一边输入一边显示//QLineEdit：：NoEcho 输入不显示，如密码//QLineEdit：：Password  密码输入方式，输入的时候显示掩码，离开显示星号QString str = QInputDialog::getText(this,"输入文本对话框","请输入姓名:",QLineEdit::Normal,"ROOK",   //默认输入&ok); //是否输入成功if(ok && !str.isEmpty()){ui->plainTextEdit->appendPlainText(str);}
}void MainWindow::on_pushButtonInputInt_clicked()
{bool ok = false;int value = QInputDialog::getInt(this,"输入整数对话框","请输入字体大小:",ui->plainTextEdit->font().pointSize(),   //默认输入10,80,  //输入整数的最大最小值1,&ok); //是否输入成功if(ok){QFont font = ui->plainTextEdit->font();font.setPointSize(value);ui->plainTextEdit->setFont(font);}
}void MainWindow::on_pushButtonInputFloat_clicked()
{bool ok = false;double value = QInputDialog::getDouble(this,"输入浮点数对话框","请输入一个浮点数:",3.14,   //默认输入1.0,100,  //输入整数的最大最小值2,  //小数点后面位数&ok); //是否输入成功if(ok){QString str = QString::asprintf("输入了以恶搞浮点数:%.2f",value);ui->plainTextEdit->appendPlainText(str);}
}void MainWindow::on_pushButtonSelectItem_clicked()
{bool ok = false;QStringList items = {"软件工程师","硬件工程师","测试工程师"};QString str = QInputDialog::getItem(this,"列表选择对话框","请选择岗位：",items, //有哪些可选项1,  //默认选项true, //是否可编辑&ok);if(ok && !str.isEmpty()){ui->plainTextEdit->appendPlainText(str);}
}void MainWindow::on_pushButtonQuestion_clicked()
{QMessageBox::StandardButton ret = QMessageBox::question(this,"问题消息框","内容已经修改，是否保存", //提示的内容QMessageBox::Yes | QMessageBox::No | QMessageBox::Cancel,QMessageBox::NoButton);  //默认选项if(ret == QMessageBox::Yes){ui->plainTextEdit->appendPlainText("已选择: Yes");}else if(ret == QMessageBox::No){ui->plainTextEdit->appendPlainText("已选择: No");}else if(ret == QMessageBox::Cancel){ui->plainTextEdit->appendPlainText("已选择: 取消");}else{ui->plainTextEdit->appendPlainText("未选择");}
}void MainWindow::on_pushButtonMessage_clicked()
{QMessageBox::information(this,"消息提示框","文件已经保存！", //提示的内容QMessageBox::Ok,QMessageBox::NoButton);  //默认选项
}void MainWindow::on_pushButtonWarning_clicked()
{QMessageBox::warning(this,"消息提示框","文件被篡改！");  //默认选项
}void MainWindow::on_pushButtonWarningSerious_clicked()
{QMessageBox::critical(this,"危机消息提示框","系统即将重启！");  //默认选项
}void MainWindow::on_pushButtonVersion_clicked()
{QMessageBox::about(this,"About消息提示框","hahahha！");  //默认选项
}void MainWindow::on_pushButtonVersionQT_clicked()
{QMessageBox::aboutQt(this,"aboutQt消息提示框");  //默认选项
}void MainWindow::on_pushButton_clicked()
{ui->plainTextEdit->clear();
}

二 自定义对话框 使用类对象的对外的接口完成窗口之间的通讯

2.1 调整行列的自定义对话框

• 步骤：Add new->新建设计师类（）->设计当前类的窗口样式->定义接口
• 功能：单击调整行列按钮，弹出对话框，修改spinbox中对应的行列数，点击确定，对应表格中的行列会发生变化
• mainwindow.h 主函数调用的时候，需要包含该类的头文件#include "dialogresize.h"，定义接口
• 知识点：点击确定按钮，或者关闭按钮，如果不需要，实现的时候 accept（）或者reject（） / close()即可

private:Ui::MainWindow *ui;DialogResize *dialogResize;DialogHeader *dialogHeader;DialogLocation *dialogLocation;

“dialogresize.h”

#ifndef DIALOGRESIZE_H
#define DIALOGRESIZE_H#include <QDialog>namespace Ui {
class DialogResize;
}class DialogResize : public QDialog
{Q_OBJECTpublic:explicit DialogResize(QWidget *parent = nullptr);~DialogResize();int getRow();int getCol();
private slots:void on_pushButtonok_clicked();void on_pushButtonCancle_clicked();private:Ui::DialogResize *ui;
};#endif // DIALOGRESIZE_H

“dialogresize.cpp”

#include "dialogresize.h"
#include "ui_dialogresize.h"DialogResize::DialogResize(QWidget *parent) :QDialog(parent),ui(new Ui::DialogResize)
{ui->setupUi(this);
}DialogResize::~DialogResize()
{delete ui;
}int DialogResize::getRow()
{return ui->spinBoxRow->value();
}int DialogResize::getCol()
{return ui->spinBoxCol->value();
}void DialogResize::on_pushButtonok_clicked()
{accept();
}void DialogResize::on_pushButtonCancle_clicked()
{reject();
}

2.2 编辑表头按钮

• 功能：点击编辑表头按钮，对话框中会同步显示出已有的表头信息，如果在对话框中编辑表头，点击确定，那么对话框将关闭，对应的表的表头也将发生变化
• 知识点1：在当前的设计师类中，新建了一个QStringListModel，因为对话框里面使用了listview
• 知识点2： QStringListModel模型获取listview中的字符串，用语句 model->stringList();，设置listview中的字符串，用语句model->setStringList(list);
  

#ifndef DIALOGEDITHEAD_H
#define DIALOGEDITHEAD_H#include <QDialog>
#include <QStringListModel>namespace Ui {
class DialogEditHead;
}class DialogEditHead : public QDialog
{Q_OBJECTpublic:explicit DialogEditHead(QWidget *parent = nullptr);~DialogEditHead();void setHeadList(const QStringList& list);QStringList getHeaderList();private slots:void on_pushButtonOk_clicked();void on_pushButtonOk_2_clicked();private:Ui::DialogEditHead *ui;QStringListModel *model;
};#endif // DIALOGEDITHEAD_H

#include "dialogedithead.h"
#include "ui_dialogedithead.h"DialogEditHead::DialogEditHead(QWidget *parent) :QDialog(parent),ui(new Ui::DialogEditHead)
{ui->setupUi(this);model = new QStringListModel;ui->listView->setModel(model);
}DialogEditHead::~DialogEditHead()
{delete ui;
}void DialogEditHead::setHeadList(const QStringList &list)
{model->setStringList(list);
}void DialogEditHead::on_pushButtonOk_clicked()
{accept();
}void DialogEditHead::on_pushButtonOk_2_clicked()
{reject();
}QStringList DialogEditHead::getHeaderList()
{return model->stringList();
}

2.3 定位按钮

• 功能：点击定位单元格，弹出对话框，会显示当前单元格对应的位置，在对话框中输入文本，点击确定，文本会更新在相应的单元格里面
• 知识点1：一般情况，按钮单击之后，会变成灰色 void showEvent(QShowEvent *event);，不会再变成原有的黑色，如果希望实现对话框关闭时，相应的按钮恢复成黑色，也就是恢复成可点击状态，添加函数void closeEvent(QCloseEvent *);
• 知识点2：通过对话框，更新主窗口的内容，需要定义主窗口的接口，同时在mainwindow函数中自定义相应的接口，setCellText就是在mainwindow函数中自定义的公共函数接口

     MainWindow *mainwindow = (MainWindow*)parentWidget();mainwindow->setCellText(ui->spinBoxRow->value(),ui->spinBoxCol->value(),ui->plainTextEdit->toPlainText());

#ifndef DIALOGLOCATION_H
#define DIALOGLOCATION_H#include <QDialog>namespace Ui {
class DialogLocation;
}class DialogLocation : public QDialog
{Q_OBJECTpublic:explicit DialogLocation(QWidget *parent = nullptr);~DialogLocation();void setCurrentColRow(int row, int col);void setRowColMax(int maxRow, int maxCol);private slots:void on_pushButton_clicked();void on_pushButton_2_clicked();private:Ui::DialogLocation *ui;//窗口关闭的时候调用这个函数void closeEvent(QCloseEvent *event);void showEvent(QShowEvent *event);};#endif // DIALOGLOCATION_H

#include "dialoglocation.h"
#include "ui_dialoglocation.h"
#include "mainwindow.h"
DialogLocation::DialogLocation(QWidget *parent) :QDialog(parent),ui(new Ui::DialogLocation)
{ui->setupUi(this);
}DialogLocation::~DialogLocation()
{delete ui;
}void DialogLocation::setCurrentColRow(int row, int col)
{ui->spinBoxCol->setValue(col);ui->spinBoxRow->setValue(row);
}void DialogLocation::setRowColMax(int maxRow, int maxCol)
{ui->spinBoxRow->setMaximum(maxRow-1);ui->spinBoxCol->setMaximum(maxCol-1);
}void DialogLocation::showEvent(QShowEvent *event){//把主窗口的定位组件再次设置为可以点击MainWindow *mainwindow = (MainWindow*)parentWidget();mainwindow->setActionLocationEnable(false);}void DialogLocation::closeEvent(QCloseEvent * )
{//把主窗口的定位组件再次设置为可以点击MainWindow *mainwindow = (MainWindow*)parentWidget();mainwindow->setActionLocationEnable(true);
}void DialogLocation::on_pushButton_clicked()
{//将指定位置的表格的内容设置为plaintext中的内容MainWindow *mainwindow = (MainWindow*)parentWidget();mainwindow->setCellText(ui->spinBoxRow->value(),ui->spinBoxCol->value(),ui->plainTextEdit->toPlainText());//列自增和行自增的框的相应实现if(ui->checkBoxRow->isChecked()){ui->spinBoxRow->setValue(ui->spinBoxRow->value() + 1);}if(ui->checkBoxCol->isChecked()){ui->spinBoxCol->setValue(ui->spinBoxCol->value() + 1);}
}void DialogLocation::on_pushButton_2_clicked()
{//reject(); //不会真正关闭对话框，不触发closeEvent，导致关闭对话框之后，标题栏的按钮没有恢复可点击状态close();
}

2.4 MainWindow函数

2.4.1 知识点1：新建对话框的方式有3种，

DialogResize *dialogresize = new DialogResize(this);
。。。。//删除对话框delete dialogresize;

dialogLocation = new DialogLocation(this);

    if(dialogHead == NULL){//只创建一次，可以重复使用dialogHead = new DialogEditHead(this); //这种调用方式，不需要delete,this是父节点，关闭的时候会同时关闭子节点}

2.4.2 知识点2：模态显示2种，一种是打开当前操作，其余地方不允许操作；另一种是其他地方允许操作

其它地方不允许操作

    //把自定义的对话框显示出来int ret = dialogresize->exec(); //模态显示，当前对话框工作，其他地方不允许操作if(ret == QDialog::Accepted){ //点击了确定按钮，。。。。}

其它地方允许操作

dialogLocation->show(); //以非模态方式显示

2.4.3 知识点3：获取tabelview模型种当前单元格的行列

QModelIndex index = selectionModel->currentIndex();
index.row(),
index.column()

2.4.4 获取表头信息

    QStringList list;for(int i =0; i < model->columnCount(); i++){list.append(model->headerData(i,Qt::Horizontal).toString());}

函数实现

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>
#include <QStandardItemModel>
#include <QItemSelectionModel>
#include "dialogedithead.h"
#include "dialoglocation.h"
QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget *parent = nullptr);~MainWindow();void setActionLocationEnable(bool enable);void setCellText(int row, int col, QString text);
private slots:void on_actionResize_triggered();void on_actionEditHead_triggered();void on_actionLocation_triggered();private:Ui::MainWindow *ui;QStandardItemModel *model;QItemSelectionModel *selectionModel;DialogEditHead *dialogHead = NULL;DialogLocation *dialogLocation = NULL;
};
#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "dialogresize.h"MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);setCentralWidget(ui->tableView);model = new QStandardItemModel(10,6,this);selectionModel = new QItemSelectionModel(model);ui->tableView->setModel(model);ui->tableView->setSelectionModel(selectionModel);
}MainWindow::~MainWindow()
{delete ui;
}void MainWindow::setActionLocationEnable(bool enable)
{ui->actionLocation->setEnabled(enable);
}void MainWindow::setCellText(int row, int col, QString text)
{//清除原来的选择项selectionModel->clearSelection();selectionModel->setCurrentIndex(model->index(row,col),QItemSelectionModel::Select);model->setData(model->index(row,col),text);
}void MainWindow::on_actionResize_triggered()
{DialogResize *dialogresize = new DialogResize(this);//固定对话框大小，不允许拉伸dialogresize->setWindowFlags(dialogresize->windowFlags() |Qt::MSWindowsFixedSizeDialogHint);//获取模型的当前的行列数，设置到自定义对话框，作为默认值显示dialogresize->setRowCount(model->rowCount());dialogresize->setColCount(model->columnCount());//把自定义的对话框显示出来int ret = dialogresize->exec(); //模态显示，当前对话框工作，其他地方不允许操作if(ret == QDialog::Accepted){ //点击了确定按钮int rows = dialogresize->rowCount();int cols = dialogresize->colCount();//改变tabelview的大小model->setRowCount(rows);model->setColumnCount(cols);}//删除对话框delete dialogresize;
}void MainWindow::on_actionEditHead_triggered()
{if(dialogHead == NULL){//只创建一次，可以重复使用dialogHead = new DialogEditHead(this); //这种调用方式，不需要delete,this是父节点，关闭的时候会同时关闭子节点}//将tabelview的表头都传递给这个对话框QStringList list;for(int i =0; i < model->columnCount(); i++){list.append(model->headerData(i,Qt::Horizontal).toString());}dialogHead->setHeadList(list);int ret = dialogHead->exec();if(ret == QDialog::Accepted){QStringList list = dialogHead->getHeaderList();model->setHorizontalHeaderLabels(list);}
}void MainWindow::on_actionLocation_triggered()
{ui->actionLocation->setEnabled(false); //一次只允许创建一个窗口//不同的新建方式dialogLocation = new DialogLocation(this);//设置窗口样式 显示在最顶层，这样不会被其他窗口覆盖dialogLocation->setWindowFlags(dialogLocation->windowFlags() |Qt::WindowStaysOnTopHint);//传递数据dialogLocation->setRowColMax(model->rowCount(),model->columnCount());QModelIndex index = selectionModel->currentIndex();if(index.isValid()){dialogLocation->setCurrentColRow(index.row(), index.column());}dialogLocation->show(); //以非模态方式显示}

三 自定义对话框 使用信号槽完成窗口之间的通讯

补充

• 知识点：两个窗口之间的通讯，需要定义信号和槽函数，信号一般定义在发送信号的窗口里面，槽函数一般定义在接收信号的窗口里面，在二案例的例子的基础上，对DialogLocation类进行修改，将类对象接口的通讯方式修改为信号与槽之间的通讯
• 步骤1：点击对话框的确定按钮，要发送信号；单击定位单元格按钮之后，要求图标变成灰色，关闭单元格之后，要求突变恢复黑色,因此当前操作需要发送两个信号，在DialogLocation类中添加信号，信号不需要做实现

//信号定义在信号发送者
signals:void setCellText(int row, int col,  QString  &text);void setActionEnable(bool enable);

• 步骤2：在mainwindow.h中添加信号槽，重点：由于是不同窗口之间的信号传递，接口需要定义成public类型的

//槽函数定义在信号的接收者,因为是其它窗口信号和当前窗口的槽函数关联
public slots:void setCellText2(int row, int col,  QString  &text);void setActionEnable2(bool enable);

• 步骤3：槽函数的实现，在对应的按键，也即控制对话框弹出的按钮里面进行信号的关联，在之前的代码上没有任何改动，只是对信号进行了连接

void MainWindow::on_actionLocation_triggered()
{ui->actionLocation->setEnabled(false); //一次只允许创建一个窗口//不同的新建方式dialogLocation = new DialogLocation(this);//设置窗口样式 显示在最顶层，这样不会被其他窗口覆盖dialogLocation->setWindowFlags(dialogLocation->windowFlags() |Qt::WindowStaysOnTopHint);//传递数据dialogLocation->setRowColMax(model->rowCount(),model->columnCount());QModelIndex index = selectionModel->currentIndex();if(index.isValid()){dialogLocation->setCurrentColRow(index.row(), index.column());}//关联connect(dialogLocation, SIGNAL(setCellText(int, int ,QString &)),this,SLOT(setCellText2(int, int ,QString &)));connect(dialogLocation, SIGNAL(setActionEnable(bool)),this,SLOT(setActionEnable2(bool)));dialogLocation->show(); //以非模态方式显示}

• 步骤4：在自定义窗口类中，发送信号

void DialogLocation::closeEvent(QCloseEvent * event)
{//把主窗口的定位组件再次设置为可以点击
//    MainWindow *mainwindow = (MainWindow*)parentWidget();
//    mainwindow->setActionLocationEnable(true);emit setActionEnable(true);
}void DialogLocation::showEvent(QShowEvent *event){//把主窗口的定位组件再次设置为可以点击
//    MainWindow *mainwindow = (MainWindow*)parentWidget();
//    mainwindow->setActionLocationEnable(false);emit setActionEnable(false);
}void DialogLocation::on_pushButton_clicked()
{
//    //将指定位置的表格的内容设置为plaintext中的内容
//     MainWindow *mainwindow = (MainWindow*)parentWidget();
//     mainwindow->setCellText(ui->spinBoxRow->value(),
//                             ui->spinBoxCol->value(),
//                             ui->plainTextEdit->toPlainText());QString text = ui->plainTextEdit->toPlainText();emit setCellText(ui->spinBoxRow->value(),ui->spinBoxCol->value(),text);//列自增和行自增的框的相应实现if(ui->checkBoxRow->isChecked()){ui->spinBoxRow->setValue(ui->spinBoxRow->value() + 1);}if(ui->checkBoxCol->isChecked()){ui->spinBoxCol->setValue(ui->spinBoxCol->value() + 1);}
}

四 多窗口开发 —类似WPS的同时可以打开多个窗口

• Qt主要窗口类
  
  
  
  
  
  

4.1 案例实现功能

• formedit.h

#ifndef FORMEDIT_H
#define FORMEDIT_H#include <QWidget>namespace Ui {
class FormEdit;
}class FormEdit : public QWidget
{Q_OBJECTpublic:explicit FormEdit(QWidget *parent = nullptr);~FormEdit();private:Ui::FormEdit *ui;
};#endif // FORMEDIT_H

• formedit.cpp

#include "formedit.h"
#include "ui_formedit.h"
#include <QToolBar>
#include <QVBoxLayout>FormEdit::FormEdit(QWidget *parent) :QWidget(parent),ui(new Ui::FormEdit)
{ui->setupUi(this);//设计器里面没有toolbox,手动创建QToolBar *bar  = new QToolBar(this);bar->addAction(ui->actionOpen);bar->addSeparator();bar->addAction(ui->actionFont);bar->addAction(ui->actionCut);bar->addAction(ui->actionCopy);bar->addAction(ui->actionPsate);bar->addAction(ui->actionCancle);bar->addAction(ui->actionRepeat);bar->addSeparator();bar->addAction(ui->actionClose);bar->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);//代码布局 plaintextEdit ,不能手动布局，否则手动添加的按钮没有位置了QVBoxLayout *layout = new QVBoxLayout();layout->addWidget(bar);layout->addWidget(ui->plainTextEdit);this->setLayout(layout);}FormEdit::~FormEdit()
{delete ui;
}

• mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget *parent = nullptr);~MainWindow();
private slots://void tabCloseRequested(int index);void on_tabWidget_tabCloseRequested(int index);void on_action_insideWidget_triggered();void on_action_widget_triggered();void on_action_insisdeMainwindow_triggered();void on_action_mainwindow_triggered();private:Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

• mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include  "formedit.h"
#include "mainwindow2.h"MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);ui->tabWidget->clear();  //清除tabWidget中的默认选项//让tab子窗口可关闭，有关闭按钮，但不会自动关闭，点击按钮会发送信号，需要自定义槽函数ui->tabWidget->setTabsClosable(true);//设置主窗口的默认状态是最大化this->setWindowState(Qt::WindowMaximized);
}MainWindow::~MainWindow()
{delete ui;
}void MainWindow::on_tabWidget_tabCloseRequested(int index)
{//获取对应的窗口QWidget *widget = ui->tabWidget->widget(index);widget->close();}void MainWindow::on_action_insideWidget_triggered()
{FormEdit *form = new FormEdit(this);form->setAttribute(Qt::WA_DeleteOnClose);  //设置窗体关闭时，自动销毁资源//将当前的表插入tabWidget,index是对应窗口的序号int index = ui->tabWidget->addTab(form,QString::asprintf("窗口%d",ui->tabWidget->count()+1));ui->tabWidget->setCurrentIndex(index);}void MainWindow::on_action_widget_triggered()
{FormEdit *form = new FormEdit(this);form->setAttribute(Qt::WA_DeleteOnClose);  //设置窗体关闭时，自动销毁资源form->setWindowTitle("基于widget的独立窗口");form->setWindowFlag(Qt::Window, true);  //这一行必须加，否则显示的独立窗口没有边框form->show();
}void MainWindow::on_action_insisdeMainwindow_triggered()
{MainWindow2 *window = new MainWindow2(this);window->setAttribute(Qt::WA_DeleteOnClose);int index = ui->tabWidget->addTab(window,QString::asprintf("窗口%d",ui->tabWidget->count()+1));ui->tabWidget->setCurrentIndex(index);
}void MainWindow::on_action_mainwindow_triggered()
{MainWindow2 *window = new MainWindow2(this);window->setAttribute(Qt::WA_DeleteOnClose);  //设置窗体关闭时，自动销毁资源window->setWindowTitle("基于MainWindow2的独立窗口");window->setWindowFlag(Qt::Window, true);  //这一行必须加，否则显示的独立窗口没有边框window->show();
}

• 其余文件代码见案例三，没有改动

4.2 案例4.1知识点总结

4.2.1 案例4.1的代码，是创建新的项目，完成formedit.h函数及其实现之后，直接将案例三中的代码合成添加到当前案例，在此合成过程中，两个案例中都有mainwindow同名函数，因此案例三中的该函数需要修改名字

• 直接将案例三中涉及mainwindow的位置都修改成mainwindow2或Mainwindow2，声明#ifndef MAINWINDOW2_H ， #define MAINWINDOW2_H，头文件#include "mainwindow2.h"都要进行相应的修改
• 另外，mainwindow2.ui文件也要进行修改，选中该文件->在explorer中显示->找到mainwindow2.ui->用记事本打开->修改如下对应位置，注意此处不是所有的都改，只改一个地方
  
• 选中项目文件名untitled27->添加现有文件->将案例三中的.cpp文件，.ui 文件，以及.h文件，案例三共有12个文件，导入当前项目即可，在案例四中调用案例三中的项目，直接通过MainWindow2 *window = new MainWindow2(this);创建街接口，就可以显示

4.2.2 Tab Widget的子窗口里面默认是没有关闭按钮的，需要手动建立信号槽来是实现

• 步骤1：在mainwindow.cpp文件中的构造函数里面，添加 ui->tabWidget->setTabsClosable(true);

MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);ui->tabWidget->clear();  //清除tabWidget中的默认选项//让tab子窗口可关闭，有关闭按钮，但不会自动关闭，点击按钮会发送信号，需要自定义槽函数ui->tabWidget->setTabsClosable(true);//设置主窗口的默认状态是最大化this->setWindowState(Qt::WindowMaximized);
}

• 步骤2：在mainwindow.h文件, 自定义信号槽 void on_tabWidget_tabCloseRequested(int index);
• 步骤3：实现槽函数

void MainWindow::on_tabWidget_tabCloseRequested(int index)
{//获取对应的窗口QWidget *widget = ui->tabWidget->widget(index);widget->close();
}

4.2.3 formedit.h是头通过新建设计师类，选择Widget来实现的，和Dialog without Buttons（案例三中使用的）不同，前者无法添加toolbox来手动拖动action,后者可以，所以当前案例的做法是，还是手动创建action以及plain text eidt,但是是在formedit.cpp中来布局和添加，不能手动布局

五 MDI开发案例 多窗口

• 组件名称
  
  
  

5.1 知识点总结

• 当前项目步骤：
  （1）创建一个设计师类，选择widget,对应文件名字formdoc,在对应的ui设计界面，只添加plain text edit 组件
  （2）对于mianwindow类，在ui界面添加一个MDI area组件，然后手动添加toolbox对应的action
• 知识点1：mianwindow里面的组件，实际的操作对象是formdoc里面的plain text edit 组件，所以对应的复制粘贴等选项，需要formdoc提供对外的接口，使得点击mianwindow里面的组件时能完成对文本的相关操作
• 知识点2：MDI模式不需要手动为弹出的对话框添加取消按钮，也即每个框右上角的×

5.2 MDI模式

MDI效果图

非MDI效果图

5.3 展开模式

5.4 平铺模式

• formdoc.h

#ifndef FORMDOC_H
#define FORMDOC_H#include <QWidget>namespace Ui {
class FormDoc;
}class FormDoc : public QWidget
{Q_OBJECTpublic:explicit FormDoc(QWidget *parent = nullptr);~FormDoc();bool fileOpen();void loadFile(const QString &filename);void cut();void paste();void copy();void setFont();private:Ui::FormDoc *ui;bool m_fileOpen = false;
};#endif // FORMDOC_H

• formdoc.cpp

#include "formdoc.h"
#include "ui_formdoc.h"
#include <QFile>
#include <QTextStream>
#include <QFileInfo>
#include <QFontDialog>
FormDoc::FormDoc(QWidget *parent) :QWidget(parent),ui(new Ui::FormDoc)
{ui->setupUi(this);this->setAttribute(Qt::WA_DeleteOnClose);  //窗口关闭消除资源
}FormDoc::~FormDoc()
{delete ui;
}bool FormDoc::fileOpen()
{return m_fileOpen;
}void FormDoc::loadFile(const QString &filename)
{QFile file(filename);if(file.open(QIODevice::ReadOnly | QIODevice::Text)){QTextStream stream(&file);ui->plainTextEdit->clear();ui->plainTextEdit->setPlainText(stream.readAll());file.close();m_fileOpen = true;//把文件名作为窗口标题 filename是文件路径QFileInfo info(filename);QString name = info.fileName();this->setWindowTitle(name);}
}void FormDoc::cut(){ui->plainTextEdit->cut();
}void FormDoc::paste()
{ui->plainTextEdit->paste();
}void FormDoc::copy()
{ui->plainTextEdit->copy();
}void FormDoc::setFont()
{QFont font = ui->plainTextEdit->font();  //获取当前字体bool ok;font = QFontDialog:: getFont(&ok, font);ui->plainTextEdit->setFont(font);
}

• mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget *parent = nullptr);~MainWindow();private slots:void on_actionNew_triggered();void on_actionOpen_triggered();void on_actionCloseALL_triggered();void on_actionCopy_triggered();void on_actionCut_triggered();void on_actionFont_triggered();void on_actionPaste_triggered();void on_actionMDI_toggled(bool arg1);void on_actionExpand_triggered();void on_actionPing_triggered();private:Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

• mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "formdoc.h"
#include <QMdiSubWindow>
#include <QFileDialog>
#include  <QDebug>MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);
}MainWindow::~MainWindow()
{delete ui;
}//新建文档
void MainWindow::on_actionNew_triggered()
{FormDoc *form = new FormDoc(this);//把新建的床口添加到MDIui->mdiArea->addSubWindow(form);//把当前新的文档编辑窗口，以独立的窗口显示form->show();
}void MainWindow::on_actionOpen_triggered()
{//如果当前MDI没有任何子窗口，open直接创建新的子窗口//MDI当前已经有子窗口，就创新新的窗口bool newNewForm = false;FormDoc *form = NULL;if(ui->mdiArea->subWindowList().count() == 0){newNewForm  = true;}else {//去除当前激活的窗口form = (FormDoc*)ui->mdiArea->activeSubWindow()->widget();if(form->fileOpen()){newNewForm = true;}}//打开文件对话框QString filename = QFileDialog::getOpenFileName(this, "打开一个文件", QDir::currentPath(),"源文件(*.h *.cpp);;文本文件(*.txt);;所有文件(*.*)");if(filename.isEmpty()){return;}if(newNewForm){FormDoc *form2 = new FormDoc(this);ui->mdiArea->addSubWindow(form2);form2->show();form2->loadFile(filename);}
}void MainWindow::on_actionCloseALL_triggered()
{ui->mdiArea->closeAllSubWindows();
}void MainWindow::on_actionCopy_triggered()
{FormDoc *form = (FormDoc*)ui->mdiArea->activeSubWindow()->widget();form->copy();
}void MainWindow::on_actionCut_triggered()
{FormDoc *form = (FormDoc*)ui->mdiArea->activeSubWindow()->widget();form->cut();
}void MainWindow::on_actionFont_triggered()
{FormDoc *form = (FormDoc*)ui->mdiArea->activeSubWindow()->widget();form->setFont();
}void MainWindow::on_actionPaste_triggered()
{FormDoc *form = (FormDoc*)ui->mdiArea->activeSubWindow()->widget();form->paste();
}void MainWindow::on_actionMDI_toggled(bool check)
{if(check){ui->mdiArea->setViewMode(QMdiArea::TabbedView);ui->actionPing->setEnabled(false);ui->actionExpand->setEnabled(false);//设置MDI子窗口的tab关闭按钮可以使用ui->mdiArea->setTabsClosable(true);}else{ui->mdiArea->setViewMode(QMdiArea::SubWindowView);ui->actionPing->setEnabled(true);ui->actionExpand->setEnabled(true);}
}void MainWindow::on_actionExpand_triggered()
{ui->mdiArea->cascadeSubWindows();
}void MainWindow::on_actionPing_triggered()
{ui->mdiArea->tileSubWindows();
}