Qt入门－提示、警告、错误、询问、关于对话框

QMessageBox类提供了常用的弹出式对话框：提示、警告、错误、询问、关于对话框

原型如下：

[cpp] view
plaincopy

void about ( QWidget * parent, const QString & title, const QString & text )

void aboutQt ( QWidget * parent, const QString & title = QString() )

StandardButton critical ( QWidget * parent, const QString & title, const QString & text, StandardButtons buttons = Ok, StandardButton defaultButton = NoButton )

StandardButton information ( QWidget * parent, const QString & title, const QString & text, StandardButtons buttons = Ok, StandardButton defaultButton = NoButton )

StandardButton question ( QWidget * parent, const QString & title, const QString & text, StandardButtons buttons = Ok, StandardButton defaultButton = NoButton )

StandardButton warning ( QWidget * parent, const QString & title, const QString & text, StandardButtons buttons = Ok, StandardButton defaultButton = NoButton )

（1）title表示标题

（2）text是对话框中的内容信息

（3）buttons是要显示的按钮，它可以是：

[cpp] view
plaincopy

NoButton = 0x00000000,

Ok = 0x00000400,

Save = 0x00000800,

SaveAll = 0x00001000,

Open = 0x00002000,

Yes = 0x00004000,

YesToAll = 0x00008000,

No = 0x00010000,

NoToAll = 0x00020000,

Abort = 0x00040000,

Retry = 0x00080000,

Ignore = 0x00100000,

Close = 0x00200000,

Cancel = 0x00400000,

Discard = 0x00800000,

Help = 0x01000000,

Apply = 0x02000000,

Reset = 0x04000000,

RestoreDefaults = 0x08000000,

（4）defaultButton是默认激活的按钮

（5）对话框的返回值即是用户最终点击的按钮。



示例：

[cpp] view
plaincopy

void Dialog::criticalMessage()

{

QMessageBox::StandardButton reply;

reply = QMessageBox::critical(this, tr("QMessageBox::critical()"),

MESSAGE,

QMessageBox::Abort | QMessageBox::Retry | QMessageBox::Ignore);

if (reply == QMessageBox::Abort)

criticalLabel->setText(tr("Abort"));

else if (reply == QMessageBox::Retry)

criticalLabel->setText(tr("Retry"));

else

criticalLabel->setText(tr("Ignore"));

}



void Dialog::informationMessage()

{

QMessageBox::StandardButton reply;

reply = QMessageBox::information(this, tr("QMessageBox::information()"), MESSAGE);

if (reply == QMessageBox::Ok)

informationLabel->setText(tr("OK"));

else

informationLabel->setText(tr("Escape"));

}



void Dialog::questionMessage()

{

QMessageBox::StandardButton reply;

reply = QMessageBox::question(this, tr("QMessageBox::question()"),

MESSAGE,

QMessageBox::Yes | QMessageBox::No | QMessageBox::Cancel);

if (reply == QMessageBox::Yes)

questionLabel->setText(tr("Yes"));

else if (reply == QMessageBox::No)

questionLabel->setText(tr("No"));

else

questionLabel->setText(tr("Cancel"));

}



void Dialog::warningMessage()

{

QMessageBox msgBox(QMessageBox::Warning, tr("QMessageBox::warning()"),

MESSAGE, 0, this);

msgBox.addButton(tr("Save &Again"), QMessageBox::AcceptRole);

msgBox.addButton(tr("&Continue"), QMessageBox::RejectRole);

if (msgBox.exec() == QMessageBox::AcceptRole)

warningLabel->setText(tr("Save Again"));

else

warningLabel->setText(tr("Continue"));



}

界面：