- Qt 5.15
- Qt NFC
- C++ Classes
- QNdefRecord
- Qt 5.15.19 Reference Documentation

# QNdefRecord Class

The QNdefRecord class provides an NFC NDEF record. More...

Header: | #include <QNdefRecord>
qmake: | QT += nfc
Since: | Qt 5.2
Inherited By: | QNdefNfcSmartPosterRecord, QNdefNfcTextRecord, and QNdefNfcUriRecord

This class was introduced in Qt 5.2.

- List of all members, including inherited members

## Public Types

enum | TypeNameFormat { Empty, NfcRtd, Mime, Uri, ExternalRtd, Unknown }

## Public Functions

| QNdefRecord(const QNdefRecord &other)
| QNdefRecord()
QNdefRecord & | operator=(const QNdefRecord &other)
| ~QNdefRecord()
QByteArray | id() const
bool | isEmpty() const
bool | isRecordType() const
QByteArray | payload() const
void | setId(const QByteArray &id)
void | setPayload(const QByteArray &payload)
void | setType(const QByteArray &type)
void | setTypeNameFormat(TypeNameFormat typeNameFormat)
QByteArray | type() const
TypeNameFormat | typeNameFormat() const
bool | operator!=(const QNdefRecord &other) const
bool | operator==(const QNdefRecord &other) const

## Macros

| Q_DECLARE_ISRECORDTYPE_FOR_NDEF_RECORD(className, typeNameFormat, type)
| Q_DECLARE_NDEF_RECORD(className, typeNameFormat, type, initialPayload)

## Detailed Description

QNdefRecord and derived classes are used to parse the contents of NDEF messages and create new NDEF messages.

Use typeNameFormat() and setTypeNameFormat() to get and set the type name format of the NDEF record.

Use type() and setType() to get and set the type of the NDEF record.

Use id() and setId() to get and set the id of the NDEF record.

Use payload() and setPayload() to get and set the NDEF record payload. isEmpty() can be used to test if the payload is empty.

QNdefRecord is an implicitly shared class. This means you can efficiently convert between QNdefRecord and specialized record classes. The isRecordType() template function can be used to test if a conversion is possible. The following example shows how to test if a QNdefRecord is an NFC RTD Text record and extract the text information from it.

     if (record.isRecordType<QNdefNfcTextRecord>()) {
         QNdefNfcTextRecord textRecord(record);

         qDebug() << textRecord.text();
     }

### Creating Specialized NDEF Record Classes

Specialized NDEF record classes can be easily created with the Q_DECLARE_NDEF_RECORD() and Q_DECLARE_ISRECORDTYPE_FOR_NDEF_RECORD() macros. The following example shows the class declaration of the hypothetical example.com:f record type that encapsulates a single int property foo.

     class ExampleComF : public QNdefRecord
     {
     public:
         Q_DECLARE_NDEF_RECORD(ExampleComF, QNdefRecord::ExternalRtd, "example.com:f",
                               QByteArray(sizeof(int), char(0)))

         int foo() const;
         void setFoo(int v);
     };

     Q_DECLARE_ISRECORDTYPE_FOR_NDEF_RECORD(ExampleComF, QNdefRecord::ExternalRtd, "example.com:f")

The developer only needs to provide implementations for the `foo()` and `setFoo()` functions that parse and set the contents of the NDEF record's payload.

## Member Type Documentation

### enum QNdefRecord::TypeNameFormat

This enum describes the type name format of an NDEF record.

Constant | Value | Description
--- | --- | ---
`QNdefRecord::Empty` | `0x00` | An empty NDEF record, the record does not contain a payload
`QNdefRecord::NfcRtd` | `0x01` | The NDEF record type is defined by an NFC RTD Specification
`QNdefRecord::Mime` | `0x02` | The NDEF record type follows the construct described in RFC 2046
`QNdefRecord::Uri` | `0x03` | The NDEF record type follows the construct described in RFC 3986
`QNdefRecord::ExternalRtd` | `0x04` | The NDEF record type follows the construct for external type names described the NFC RTD Specification
`QNdefRecord::Unknown` | `0x05` | The type of the record is unknown and should be treated similar to content with MIME type 'application/octet-stream' without further context

## Member Function Documentation

### QNdefRecord::QNdefRecord(const QNdefRecord &other)

Constructs a new NDEF record that is a copy of other.

### QNdefRecord::QNdefRecord()

Constructs a new empty NDEF record.

### QNdefRecord &QNdefRecord::operator=(const QNdefRecord &other)

Assigns this NDEF record to other.

### QNdefRecord::~QNdefRecord()

Destroys the NDEF record.

### QByteArray QNdefRecord::id() const

Returns the id of the NDEF record.

See also setId().

### bool QNdefRecord::isEmpty() const

Returns true if the NDEF record contains an empty payload; otherwise return false.

This is equivalent to calling `payload().isEmpty()`.

### template <typename T> bool QNdefRecord::isRecordType() const

Returns true if the NDEF record is of the specified record type; otherwise returns false.

### QByteArray QNdefRecord::payload() const

Returns the payload of the NDEF record.

See also setPayload().

### void QNdefRecord::setId(const QByteArray &id)

Sets the id of the NDEF record to id.

See also id().

### void QNdefRecord::setPayload(const QByteArray &payload)

Sets the payload of the NDEF record to payload.

See also payload().

### void QNdefRecord::setType(const QByteArray &type)

Sets the type of the NDEF record to type.

See also type().

### void QNdefRecord::setTypeNameFormat(TypeNameFormat typeNameFormat)

Sets the type name format of the NDEF record to typeNameFormat.

See also typeNameFormat().

### QByteArray QNdefRecord::type() const

Returns the type of the NDEF record.

See also setType().

### TypeNameFormat QNdefRecord::typeNameFormat() const

Returns the type name format of the NDEF record.

See also setTypeNameFormat().

### bool QNdefRecord::operator!=(const QNdefRecord &other) const

Returns true if this NDEF record does not equal other; otherwise return false.

### bool QNdefRecord::operator==(const QNdefRecord &other) const

Returns true if other and this NDEF record are the same.

## Macro Documentation

### Q_DECLARE_ISRECORDTYPE_FOR_NDEF_RECORD(className, typeNameFormat, type)

This macro declares a template specialization for the QNdefRecord::isRecordType() function.

This macro should be used in the header file directly after the definition of a specialized NDEF record class.

className is the name of the specialized class, typeNameFormat is the appropriate QNdefRecord::TypeNameFormat for the custom type and type is the type without the NID or NSS prefixes. That is example.com:f not urn:nfc:ext:example.com:f.

See the section on Creating specialized NDEF record classes for details.

See also Q_DECLARE_NDEF_RECORD().

### Q_DECLARE_NDEF_RECORD(className, typeNameFormat, type, initialPayload)

This macro declares default and copy constructors for specialized NDEF record classes.

className is the name of the specialized class, typeNameFormat is the appropriate QNdefRecord::TypeNameFormat for the custom type and type is the type without the NID or NSS prefixes. That is example.com:f not urn:nfc:ext:example.com:f. initialPayload is the initial payload of an empty record, it must be a QByteArray or a type that can be implicitly converted into a QByteArray.

See the section on Creating specialized NDEF record classes for details.

See also Q_DECLARE_ISRECORDTYPE_FOR_NDEF_RECORD().