The use of various message box dialog boxes in Qt

When the program is running, it is often necessary to prompt the user for some information, such as warnings, hints, suggestions and the like. These things basically interact with the user through the message box, which is mainly realized by the QMessageBox class in Qt.

Message boxes are generally divided into seven types:

Question query message box: provide a simple query for normal operation
Information message box: Provides a hint for normal operation
Warning prompt message box: remind the user that an error has occurred
Critical warning message box: warns the user that a serious error has occurred
About message box: custom about information
AboutQt about the Qt message box: information about Qt itself
Custom custom message box: customize the message box yourself

See the source code and analysis for specific usage:

Dialog.pro

#-------------------------------------------------
#
# Project created by QtCreator 2015-10-24T17:32:35
#
#-------------------------------------------------

QT    += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = Dialog
TEMPLATE = app

SOURCES += main.cpp
    dialog.cpp

HEADERS += dialog.h

dialog.h

#ifndefDIALOG_H
#defineDIALOG_H

#include<QDialog>
#include<QGridLayout>
#include<QPushButton>
#include<QLabel>
#include<QMessageBox>
class Dialog: public QDialog
{
  Q_OBJECT

public:
  Dialog(QWidget *parent = 0);
  ~Dialog();
public://配置部件和布局
  QLabel *label;
  QPushButton *QuestionBtn,*InformationBtn,*WarningBtn,*CriticalBtn,*AboutBtn,*AboutQtBtn,*CustomBtn;
  QGridLayout *layout,*layoutLabel,*layoutBtn;
protected slots://各种按钮的槽
  void slotQuestion();
  void slotInformation();
  void slotWarning();
  void slotCritical();
  void slotAbout();
  void slotAboutQt();
  void slotCustom();
};

#endif// DIALOG_H

dialog.cpp

#include"dialog.h"

Dialog::Dialog(QWidget *parent)
  : QDialog(parent)
{
  setWindowTitle("QMessageBox");

  QuestionBtn=new QPushButton("Question");
  InformationBtn=new QPushButton("Information");
  WarningBtn=new QPushButton("Warning");
  CriticalBtn=new QPushButton("Critical");
  AboutBtn=new QPushButton("About");
  AboutQtBtn=new QPushButton("AboutQt");
  CustomBtn=new QPushButton("Custom");

  label=new QLabel("About Qt MessageBox:");
  layout=new QGridLayout(this);
  layoutLabel=new QGridLayout;
  layoutBtn=new QGridLayout;
  layoutLabel->addWidget(label,0,0);
  layoutBtn->addWidget(QuestionBtn,1,0);
  layoutBtn->addWidget(InformationBtn,1,1);
  layoutBtn->addWidget(WarningBtn,2,0);
  layoutBtn->addWidget(CriticalBtn,2,1);
  layoutBtn->addWidget(AboutBtn,3,0);
  layoutBtn->addWidget(AboutQtBtn,3,1);
  layoutBtn->addWidget(CustomBtn,4,0);
  layoutBtn->setSpacing(15);

  //嵌套布局
  layout->addLayout(layoutLabel,0,0);
  layout->addLayout(layoutBtn,1,0);
  setFixedSize(300,220);//固定大小

  connect(QuestionBtn,SIGNAL(clicked()),this,SLOT(slotQuestion()));
  connect(InformationBtn,SIGNAL(clicked()),this,SLOT(slotInformation()));
  connect(WarningBtn,SIGNAL(clicked()),this,SLOT(slotWarning()));
  connect(CriticalBtn,SIGNAL(clicked()),this,SLOT(slotCritical()));
  connect(AboutBtn,SIGNAL(clicked()),this,SLOT(slotAbout()));
  connect(AboutQtBtn,SIGNAL(clicked()),this,SLOT(slotAboutQt()));
  connect(CustomBtn,SIGNAL(clicked()),this,SLOT(slotCustom()));
}

Dialog::~Dialog()
{

}

//直接调用AboutQt，设置句柄和标题即可
void Dialog::slotAboutQt(){
 QMessageBox::aboutQt(this,"This is the title");
}

//以下三个函数均是设置句柄标题和信息即可，也可以在最后设置默认按钮，一般默认的是QMessageBox::Ok。
void Dialog::slotAbout(){
   QMessageBox::about(this,"About","This is the label.");
}
void Dialog::slotCritical(){
  QMessageBox::critical(this,"Critical","This is the label.");
}
void Dialog::slotInformation(){
 QMessageBox::information(this,"Information","This is the label.");
}

//自定义消息框
void Dialog::slotCustom(){

  QMessageBox customMsgBox;
  customMsgBox.setWindowTitle("Custom message box");

  //添加按键
  QPushButton *lockBtn=customMsgBox.addButton("Lock",QMessageBox::ActionRole);
  QPushButton *unlockBtn=customMsgBox.addButton("Unlock",QMessageBox::ActionRole);
  QPushButton *cancelBtn=customMsgBox.addButton(QMessageBox::Cancel);//注意cancel不能指定Text

  //customMsgBox.setIconPixmap(QPixmap("a.png"));//设置图片
  customMsgBox.setText("This is the label");
  customMsgBox.exec();//执行消息框

  QPushButton *msg=(QPushButton*)customMsgBox.clickedButton();//接受按键信息

  //判断按键
  if(msg==lockBtn)
    label->setText("Custom button /lock");

  if(msg==unlockBtn)
    label->setText("Custom button /unlock");

  if(msg==cancelBtn)
    label->setText("Custom button /cancel");

}

void Dialog::slotQuestion(){
  //QMessageBox::**question()**函数，传入句柄，标题，文本，按钮值，返回按键对应的值，最后也可以加默认按键的位置
  int msg=QMessageBox::question(this,"Question","This is the label.",QMessageBox::Ok|QMessageBox::Cancel);

  //判断选择信息
  switch(msg){
  case QMessageBox::Ok:
    label->setText("Question button /OK");
    break;
  case QMessageBox::Cancel:
    label->setText("Question button /Cancel");
    break;
  default:
    break;
  }
}

void Dialog::slotWarning(){

  //QmessageBox::warning()函数同Question函数
  int msg=QMessageBox::warning(this,"Question","This is the label.",QMessageBox::Save|QMessageBox::Discard|QMessageBox::Cancel,QMessageBox::Save);

  switch(msg){//判断选择信息
  case QMessageBox::Save:
    label->setText("Warning button /Save");
    break;
  case QMessageBox::Cancel:
    label->setText("Warning button /Cancel");
    break;
  case QMessageBox::Discard:
    label->setText("Warning button /Discard");
    break;
  default:
    break;
  }

}

##main.cpp

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

int main(intargc,char*argv[])
{
  QApplicationa(argc, argv);
  Dialog w;
  w.show();

  return a.exec();
}

run screenshot

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The use of various message box dialog boxes in Qt

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