All subclasses of
QXmlReaderread the input XML document from this class.
This class recognizes the encoding of the data by reading the encoding declaration in the XML file if it finds one, and reading the data using the corresponding encoding. If it does not find an encoding declaration, then it assumes that the data is either in UTF-8 or UTF-16, depending on whether it can find a byte-order mark.
There are two ways to populate the input source with data: you can construct it with a
QIODevice* so that the input source reads the data from that device. Or you can set the data explicitly with one of the
Usually you either construct a
QXmlInputSourcethat works on a
QIODevice* or you construct an empty
QXmlInputSourceand set the data with
setData(). There are only rare occasions where you would want to mix both methods.
fetchData()are useful if you want to do something with the data other than parsing, e.g. displaying the raw XML file. The benefit of using the QXmlInputClass in such cases is that it tries to use the correct encoding.
- param dev
Constructs an input source which contains no data.
Constructs an input source and gets the data from device
devis not open, it is opened in read-only mode. If
devis 0 or it is not possible to read from the device, the input source will contain no data.
- Return type
Returns the data the input source contains or an empty string if the input source does not contain any data.
This function reads more data from the device that was set during construction. If the input source already contained data, this function deletes that data first.
This object contains no data after a call to this function if the object was constructed without a device to read data from or if this function was not able to get more data from the device.
There are two occasions where a fetch is done implicitly by another function call: during construction (so that the object starts out with some initial data where available), and during a call to
next()(if the data had run out).
You don’t normally need to use this function if you use
beginning – bool
- Return type
This function reads the XML file from
dataand tries to recognize the encoding. It converts the raw data
QStringand returns it. It tries its best to get the correct encoding for the XML file.
beginningis true, this function assumes that the data starts at the beginning of a new XML document and looks for an encoding declaration. If
beginningis false, it converts the raw data using the encoding determined from prior calls.
- Return type
Returns the next character of the input source. If this function reaches the end of available data, it returns QXmlInputSource::EndOfData. If you call after that, it tries to fetch more data by calling
fetchData(). If the
fetchData()call results in new data, this function returns the first character of that data; otherwise it returns QXmlInputSource::EndOfDocument.
Readers, such as
QXmlSimpleReader, will assume that the end of the XML document has been reached if the this function returns QXmlInputSource::EndOfDocument, and will check that the supplied input is well-formed. Therefore, when reimplementing this function, it is important to ensure that this behavior is duplicated.
In the case that the underlying data source is a
QIODevice, the current position in the device is not automatically set to the start of input. Call
seek(0) on the device to do this.
dat – str
© 2020 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.