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:
具体用法见源码以及分析:
#-------------------------------------------------
#
# 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
#ifndef DIALOG_H
#define DIALOG_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
#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;
}
}
#include "dialog.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Dialog w;
w.show();
return a.exec();
}