深入理解Qt中各种消息框对话框的使用
最近在学习Qt框架,今天学习了一下消息框的使用, 现整理出来以作记录。
在程序运行时,经常需要提示用户一些信息,比如警告啊,提示啊,建议啊之类的东西。这些东西基本上是通过消息框与用户进行交互的,Qt中主要是用QMessageBox类来加以实现的。
消息框一般分为七种:
- Question询问消息框:为正常的操作提供一个简单的询问
- Information信息消息框:为正常操作提供一个提示
- Warning提示消息框:提醒用户发生了一个错误
- Critical警告消息框:警告用户发生了一个严重错误
- About关于消息框:自定义的关于信息
- AboutQt关于Qt消息框:Qt自身的关于信息
- Custom自定义消息框:自己定制消息框
具体用法见源码以及分析:
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(); }
运行截图
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