QFileSystemWatcher

The QFileSystemWatcher class provides an interface for monitoring files and directories for modifications. More

Inheritance diagram of PySide2.QtCore.QFileSystemWatcher

Synopsis

Functions

Detailed Description

QFileSystemWatcher monitors the file system for changes to files and directories by watching a list of specified paths.

Call addPath() to watch a particular file or directory. Multiple paths can be added using the addPaths() function. Existing paths can be removed by using the removePath() and removePaths() functions.

QFileSystemWatcher examines each path added to it. Files that have been added to the QFileSystemWatcher can be accessed using the files() function, and directories using the directories() function.

The fileChanged() signal is emitted when a file has been modified, renamed or removed from disk. Similarly, the directoryChanged() signal is emitted when a directory or its contents is modified or removed. Note that QFileSystemWatcher stops monitoring files once they have been renamed or removed from disk, and directories once they have been removed from disk.

See also

QFile QDir

class PySide2.QtCore.QFileSystemWatcher([parent=None])

PySide2.QtCore.QFileSystemWatcher(paths[, parent=None])

param parent

PySide2.QtCore.QObject

param paths

list of strings

Constructs a new file system watcher object with the given parent .

Constructs a new file system watcher object with the given parent which monitors the specified paths list.

PySide2.QtCore.QFileSystemWatcher.addPath(file)
Parameters

file – str

Return type

bool

Adds path to the file system watcher if path exists. The path is not added if it does not exist, or if it is already being monitored by the file system watcher.

If path specifies a directory, the directoryChanged() signal will be emitted when path is modified or removed from disk; otherwise the fileChanged() signal is emitted when path is modified, renamed or removed.

If the watch was successful, true is returned.

Reasons for a watch failure are generally system-dependent, but may include the resource not existing, access failures, or the total watch count limit, if the platform has one.

Note

There may be a system dependent limit to the number of files and directories that can be monitored simultaneously. If this limit is been reached, path will not be monitored, and false is returned.

PySide2.QtCore.QFileSystemWatcher.addPaths(files)
Parameters

files – list of strings

Return type

list of strings

Adds each path in paths to the file system watcher. Paths are not added if they not exist, or if they are already being monitored by the file system watcher.

If a path specifies a directory, the directoryChanged() signal will be emitted when the path is modified or removed from disk; otherwise the fileChanged() signal is emitted when the path is modified, renamed, or removed.

The return value is a list of paths that could not be watched.

Reasons for a watch failure are generally system-dependent, but may include the resource not existing, access failures, or the total watch count limit, if the platform has one.

Note

There may be a system dependent limit to the number of files and directories that can be monitored simultaneously. If this limit has been reached, the excess paths will not be monitored, and they will be added to the returned QStringList .

PySide2.QtCore.QFileSystemWatcher.directories()
Return type

list of strings

Returns a list of paths to directories that are being watched.

See also

files()

PySide2.QtCore.QFileSystemWatcher.files()
Return type

list of strings

Returns a list of paths to files that are being watched.

See also

directories()

PySide2.QtCore.QFileSystemWatcher.removePath(file)
Parameters

file – str

Return type

bool

Removes the specified path from the file system watcher.

If the watch is successfully removed, true is returned.

Reasons for watch removal failing are generally system-dependent, but may be due to the path having already been deleted, for example.

PySide2.QtCore.QFileSystemWatcher.removePaths(files)
Parameters

files – list of strings

Return type

list of strings

Removes the specified paths from the file system watcher.

The return value is a list of paths which were not able to be unwatched successfully.

Reasons for watch removal failing are generally system-dependent, but may be due to the path having already been deleted, for example.