14.1. Input Masks

14.1. Input Masks
	Chapter 14. Validation and Regular Expressions

[ fromfile: validation.xml id: inputmask ]

An input mask is an active pattern that controls what can be typed into an input widget by the user.
An inputMask is a QString property of a QLineEdit which can contain mask characters to constrain the incoming text.
The string consists of special, predefined mask characters and (optional) ordinary characters that occupy corresponding positions in the entered string.

Table 14.1. Mask Characters

Character	Required Character in That Position
A	ASCII alphabetic character - uppercase or lowercase
N	ASCII alphanumeric character - uppercase or lowercase
X	ASCII any character
D	ASCII nonzero digit
9	ASCII digit
H	Hexadecimal digit
B	Binary digit

Lowercase versions of the mask letters listed in Table 14.1 specify that the corresponding input characters are permitted in that position but not required.
Using zero (0) instead of nine (9) indicates that an ASCII digit is permitted in that position but not required.
# indicates that an ASCII digit or a plus (+) or a minus (–) is permitted in that position but not required.

Table 14.2. Mask Meta Characters

Character	Effect
>	The following alphabetic characters are uppercased
<	The following alphabetic characters are lowercased
!	No further case conversion
\	Escape character

Example 14.1. src/validate/inputmask/masktestform.h

[ . . . . ]
class MaskTestForm : public QWidget {
   Q_OBJECT
public:
   MaskTestForm();
public slots:  
   void showResult();
   void installMask();
   void again();
private:
   QLineEdit* m_InputMask;
   QLineEdit* m_StringEntry;
   QLabel* m_Result;
   void setupForm();
};
[ . . . . ]

Example 14.2. src/validate/inputmask/masktestform.cpp

[ . . . . ]
MaskTestForm::MaskTestForm(): m_InputMask(new QLineEdit), 
    m_StringEntry(new QLineEdit), m_Result(new QLabel) {
    setupForm();
    move(500, 500); 
}
 
void MaskTestForm::setupForm() {
    setWindowTitle("Mask Test Demo");
    QPushButton* againButton = new QPushButton("Another Input Mask", this);
    QPushButton* quitButton = new QPushButton("Quit", this);
    QFormLayout *form = new QFormLayout(this);
    form->addRow("Mask String:", m_InputMask);
    form->addRow("Test Input: ", m_StringEntry);
    form->addRow("Result:", m_Result);
    connect(m_InputMask, SIGNAL(returnPressed()),
            this, SLOT(installMask()));
    connect(m_StringEntry, SIGNAL(returnPressed()),
            this, SLOT(showResult()));
[ . . . . ]
}
void MaskTestForm::installMask() {
    m_StringEntry->setInputMask(m_InputMask->text());
}
[ . . . . ]

Start in mid screen (approx).

Figure 14.1. Input Masks


Chapter 14. Validation and Regular Expressions		14.1.1. Exercises: Input Masks