User Login Dialog: Difference between revisions
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[[Category:HowTo]] | [[Category:HowTo]] | ||
[[Category:snippets]] | |||
= An example of user login dialog = | = An example of user login dialog = | ||
This code snippets shows how to implement a simple dialog window that allows the user to enter his username and password in order to make a login attempt. The dialog window will emit a signal in order to notify a listener for the login credentials. The login dialog can also presents a list of usernames to select one from. | This code snippets shows how to implement a simple dialog window that allows the user to enter his username and password in order to make a login attempt. The dialog window will emit a signal in order to notify a listener for the login credentials. The login dialog can also presents a list of usernames to select one from. | ||
The dialog also allows for the proposal of a specified username/password as it could be loaded from a settings or a configuration file. | |||
== Header file == | == Header file == | ||
<code> | <code> | ||
#include <QDialog> | |||
#include <QLabel> | |||
#include <QPushButton> | |||
#include <QDialogButtonBox> | |||
#include <QLineEdit> | |||
#include <QComboBox> | |||
#include <QGridLayout> | |||
#include <QStringList> | |||
#include <QDebug> | |||
/*! | /*! | ||
'''Makes class LoginDialog a child to its parent, QDialog | |||
*/ | |||
class LoginDialog : public QDialog | |||
{ | |||
/*! | |||
'''Turns Login Dialog into a QObject | |||
*/ | |||
Q_OBJECT | |||
private: | private: | ||
/*! | |||
* A label for the username component. | |||
*/ | |||
QLabel''' labelUsername; | |||
/*! | /*! | ||
* A label for the password. | |||
*/ | |||
QLabel''' labelPassword; | |||
/*! | /*! | ||
* An editable combo box for allowing the user | |||
* to enter his username or select it from a list. | |||
*/ | |||
QComboBox''' comboUsername; | |||
/*! | /*! | ||
* A field to let the user enters his password. | |||
*/ | |||
QLineEdit''' editPassword; | |||
/*! | /*! | ||
* The standard dialog button box. | |||
*/ | |||
QDialogButtonBox''' buttons; | |||
/*! | /*! | ||
* A method to set up all dialog components and | |||
* initialize them. | |||
*/ | |||
void setUpGUI(); | |||
public: | public: | ||
explicit LoginDialog(QWidget '''parent = 0); | |||
/*! | |||
* Sets the proposed username, that can come for instance | |||
* from a shared setting. | |||
'''username the string that represents the current username | |||
''' to display | |||
*/ | |||
void setUsername( QString&amp; username ); | |||
/*! | |||
* Sets the current password to propose to the user for the login. | |||
* password the password to fill into the dialog form | |||
*/ | |||
void setPassword( QString&amp; password ); | |||
/*! | |||
* Sets a list of allowed usernames from which the user | |||
* can pick one if he does not want to directly edit it. | |||
'''usernames a list of usernames | |||
*/ | |||
void setUsernamesList( const QStringList&amp; usernames ); | |||
signals: | signals: | ||
/*! | /*! | ||
* A signal emitted when the login is performed. | |||
* username the username entered in the dialog | |||
* password the password entered in the dialog | |||
* index the number of the username selected in the combobox | |||
*/ | |||
void acceptLogin( QString&amp; username, QString&amp; password, int&amp; indexNumber ); | |||
public slots: | |||
/*! | |||
* A lot to adjust the emitting of the signal. | |||
*/ | |||
void slotAcceptLogin(); | |||
}; | }; | ||
Line 39: | Line 109: | ||
== Implementation == | == Implementation == | ||
<code>LoginDialog::LoginDialog(QWidget '''parent) : | <code>LoginDialog::LoginDialog(QWidget '''parent) : | ||
QDialog(parent) | |||
{ | |||
setUpGUI(); | |||
setWindowTitle( tr("User Login") ); | |||
setModal( true ); | |||
} | |||
void LoginDialog::setUpGUI(){ | |||
// set up the layout | |||
QGridLayout''' formGridLayout = new QGridLayout( this ); | |||
// initialize the | // initialize the username combo box so that it is editable | ||
comboUsername = new QComboBox( this ); | |||
comboUsername->setEditable( true ); | |||
// initialize the password field so that it does not echo | |||
// characters | |||
editPassword = new QLineEdit( this ); | |||
editPassword->setEchoMode( QLineEdit::Password ); | |||
// initialize | // initialize the labels | ||
labelUsername = new QLabel( this ); | |||
labelPassword = new QLabel( this ); | |||
labelUsername->setText( tr( "Username" ) ); | |||
labelUsername->setBuddy( comboUsername ); | |||
labelPassword->setText( tr( "Password" ) ); | |||
labelPassword->setBuddy( editPassword ); | |||
// initialize buttons | |||
buttons = new QDialogButtonBox( this ); | |||
buttons->addButton( QDialogButtonBox::Ok ); | |||
buttons->addButton( QDialogButtonBox::Cancel ); | |||
buttons->button( QDialogButtonBox::Ok )->setText( tr("Login") ); | |||
buttons->button( QDialogButtonBox::Cancel )->setText( tr("Abort") ); | |||
// place components into the dialog | // connects slots | ||
connect( buttons->button( QDialogButtonBox::Cancel ), | |||
SIGNAL (clicked()), | |||
this, | |||
SLOT (close()) | |||
); | |||
connect( buttons->button( QDialogButtonBox::Ok ), | |||
SIGNAL (clicked()), | |||
this, | |||
SLOT (slotAcceptLogin()) ); | |||
// place components into the dialog | |||
formGridLayout->addWidget( labelUsername, 0, 0 ); | |||
formGridLayout->addWidget( comboUsername, 0, 1 ); | |||
formGridLayout->addWidget( labelPassword, 1, 0 ); | |||
formGridLayout->addWidget( editPassword, 1, 1 ); | |||
formGridLayout->addWidget( buttons, 2, 0, 1, 2 ); | |||
setLayout( formGridLayout ); | setLayout( formGridLayout ); | ||
Line 57: | Line 167: | ||
} | } | ||
void LoginDialog::setUsername(QString &username){ | void LoginDialog::setUsername(QString &username){ | ||
bool found = false; | |||
for( int i = 0; i < comboUsername->count() && ! found ; i++ ) | |||
if( comboUsername->itemText( i ) == username ){ | |||
comboUsername->setCurrentIndex( i ); | |||
found = true; | |||
} | |||
if( ! found ){ | if( ! found ){ | ||
int index = comboUsername->count(); | |||
qDebug() << "Select username " << index; | |||
comboUsername->addItem( username ); | |||
comboUsername- | comboUsername->setCurrentIndex( index ); | ||
} | |||
// place the focus on the password field | // place the focus on the password field | ||
editPassword->setFocus(); | |||
} | |||
void LoginDialog::setPassword(QString &password){ | void LoginDialog::setPassword(QString &password){ | ||
editPassword->setText( password ); | |||
} | |||
void LoginDialog::slotAcceptLogin(){ | void LoginDialog::slotAcceptLogin(){ | ||
QString username = comboUsername->currentText(); | |||
QString password = editPassword->text(); | |||
int index = comboUsername->currentIndex(); | |||
emit acceptLogin( username, // current username | emit acceptLogin( username, // current username | ||
password, // current password | |||
index // index in the username list | |||
); | |||
// close this dialog | // close this dialog | ||
close(); | |||
} | |||
void LoginDialog::setUsernamesList(const QStringList &usernames){ | void LoginDialog::setUsernamesList(const QStringList &usernames){ | ||
comboUsername->addItems( usernames ); | |||
} | |||
</code> | </code> | ||
Line 79: | Line 213: | ||
== Usage example == | == Usage example == | ||
<code>LoginDialog* loginDialog = new LoginDialog( this ); | <code>LoginDialog* loginDialog = new LoginDialog( this ); | ||
loginDialog->setUsername( "Luca" ); // optional | |||
connect( loginDialog, | |||
SIGNAL (acceptLogin(QString&amp;,QString&amp;,int&amp;)), | |||
this, | |||
SLOT (slotAcceptUserLogin(QString&amp;,QString&amp;))); | |||
loginDialog->exec(); | |||
</code> | </code> |
Revision as of 08:57, 25 February 2015
An example of user login dialog
This code snippets shows how to implement a simple dialog window that allows the user to enter his username and password in order to make a login attempt. The dialog window will emit a signal in order to notify a listener for the login credentials. The login dialog can also presents a list of usernames to select one from. The dialog also allows for the proposal of a specified username/password as it could be loaded from a settings or a configuration file.
Header file
#include <QDialog>
#include <QLabel>
#include <QPushButton>
#include <QDialogButtonBox>
#include <QLineEdit>
#include <QComboBox>
#include <QGridLayout>
#include <QStringList>
#include <QDebug>
/*!
'''Makes class LoginDialog a child to its parent, QDialog
*/
class LoginDialog : public QDialog
{
/*!
'''Turns Login Dialog into a QObject
*/
Q_OBJECT
private:
/*!
* A label for the username component.
*/
QLabel''' labelUsername;
/*!
* A label for the password.
*/
QLabel''' labelPassword;
/*!
* An editable combo box for allowing the user
* to enter his username or select it from a list.
*/
QComboBox''' comboUsername;
/*!
* A field to let the user enters his password.
*/
QLineEdit''' editPassword;
/*!
* The standard dialog button box.
*/
QDialogButtonBox''' buttons;
/*!
* A method to set up all dialog components and
* initialize them.
*/
void setUpGUI();
public:
explicit LoginDialog(QWidget '''parent = 0);
/*!
* Sets the proposed username, that can come for instance
* from a shared setting.
'''username the string that represents the current username
''' to display
*/
void setUsername( QString&amp; username );
/*!
* Sets the current password to propose to the user for the login.
* password the password to fill into the dialog form
*/
void setPassword( QString&amp; password );
/*!
* Sets a list of allowed usernames from which the user
* can pick one if he does not want to directly edit it.
'''usernames a list of usernames
*/
void setUsernamesList( const QStringList&amp; usernames );
signals:
/*!
* A signal emitted when the login is performed.
* username the username entered in the dialog
* password the password entered in the dialog
* index the number of the username selected in the combobox
*/
void acceptLogin( QString&amp; username, QString&amp; password, int&amp; indexNumber );
public slots:
/*!
* A lot to adjust the emitting of the signal.
*/
void slotAcceptLogin();
};
#endif // LOGINDIALOG_H
Implementation
LoginDialog::LoginDialog(QWidget '''parent) :
QDialog(parent)
{
setUpGUI();
setWindowTitle( tr("User Login") );
setModal( true );
}
void LoginDialog::setUpGUI(){
// set up the layout
QGridLayout''' formGridLayout = new QGridLayout( this );
// initialize the username combo box so that it is editable
comboUsername = new QComboBox( this );
comboUsername->setEditable( true );
// initialize the password field so that it does not echo
// characters
editPassword = new QLineEdit( this );
editPassword->setEchoMode( QLineEdit::Password );
// initialize the labels
labelUsername = new QLabel( this );
labelPassword = new QLabel( this );
labelUsername->setText( tr( "Username" ) );
labelUsername->setBuddy( comboUsername );
labelPassword->setText( tr( "Password" ) );
labelPassword->setBuddy( editPassword );
// initialize buttons
buttons = new QDialogButtonBox( this );
buttons->addButton( QDialogButtonBox::Ok );
buttons->addButton( QDialogButtonBox::Cancel );
buttons->button( QDialogButtonBox::Ok )->setText( tr("Login") );
buttons->button( QDialogButtonBox::Cancel )->setText( tr("Abort") );
// connects slots
connect( buttons->button( QDialogButtonBox::Cancel ),
SIGNAL (clicked()),
this,
SLOT (close())
);
connect( buttons->button( QDialogButtonBox::Ok ),
SIGNAL (clicked()),
this,
SLOT (slotAcceptLogin()) );
// place components into the dialog
formGridLayout->addWidget( labelUsername, 0, 0 );
formGridLayout->addWidget( comboUsername, 0, 1 );
formGridLayout->addWidget( labelPassword, 1, 0 );
formGridLayout->addWidget( editPassword, 1, 1 );
formGridLayout->addWidget( buttons, 2, 0, 1, 2 );
setLayout( formGridLayout );
}
void LoginDialog::setUsername(QString &username){
bool found = false;
for( int i = 0; i < comboUsername->count() && ! found ; i++ )
if( comboUsername->itemText( i ) == username ){
comboUsername->setCurrentIndex( i );
found = true;
}
if( ! found ){
int index = comboUsername->count();
qDebug() << "Select username " << index;
comboUsername->addItem( username );
comboUsername->setCurrentIndex( index );
}
// place the focus on the password field
editPassword->setFocus();
}
void LoginDialog::setPassword(QString &password){
editPassword->setText( password );
}
void LoginDialog::slotAcceptLogin(){
QString username = comboUsername->currentText();
QString password = editPassword->text();
int index = comboUsername->currentIndex();
emit acceptLogin( username, // current username
password, // current password
index // index in the username list
);
// close this dialog
close();
}
void LoginDialog::setUsernamesList(const QStringList &usernames){
comboUsername->addItems( usernames );
}
Usage example
LoginDialog* loginDialog = new LoginDialog( this );
loginDialog->setUsername( "Luca" ); // optional
connect( loginDialog,
SIGNAL (acceptLogin(QString&amp;,QString&amp;,int&amp;)),
this,
SLOT (slotAcceptUserLogin(QString&amp;,QString&amp;)));
loginDialog->exec();