Class: QgsCustomDropHandler

class qgis.gui.QgsCustomDropHandler

Bases: PyQt5.QtCore.QObject

Abstract base class that may be implemented to handle new types of data to be dropped in QGIS.

Implementations have three approaches they can use to handle drops.

1. The simplest approach is to implement handeFileDrop() when they need to handle dropped files (i.e. with mime type “text/uri-list”).

2. Reimplement handleCustomUriDrop() when they want to handle dropped custom QgsMimeDataUtils.Uri entries, for instance handling dropping custom entries from the browser tree (with mime type “application/x-vnd.qgis.qgis.uri”). In this case the implementation’s customUriProviderKey() must match the uri entry’s providerKey.

3. Reimplement handleMimeData() to directly handle dropped QMimeData. Subclasses should take care when overriding this method. When a drop event occurs, Qt will lock the source application of the drag for the duration of the drop event handling via handleMimeData() (e.g. dragging files from explorer to QGIS will lock the explorer window until the drop handling has been complete). Accordingly handleMimeData() implementations must return quickly and defer any intensive or slow processing.

Methods

canHandleCustomUriCanvasDrop

Returns True if the handler is capable of handling the provided mime uri when dropped onto a map canvas.

canHandleMimeData

Returns True if the handler is capable of handling the provided mime data.

childEvent

connectNotify

customEvent

customUriProviderKey

Type of custom URI recognized by the handler.

disconnectNotify

handleCustomUriCanvasDrop

Called from QGIS after a drop event with custom uri known by the handler occurs onto a map canvas.

handleCustomUriDrop

Called from QGIS after a drop event with custom URI known by the handler.

handleFileDrop

Called when the specified file has been dropped onto QGIS.

handleMimeData

Called when the specified mime data has been dropped onto QGIS.

handleMimeDataV2

Called when the specified mime data has been dropped onto QGIS.

isSignalConnected

receivers

sender

senderSignalIndex

timerEvent

canHandleCustomUriCanvasDrop(self, uri: QgsMimeDataUtils.Uri, canvas: QgsMapCanvas) → bool

Returns True if the handler is capable of handling the provided mime uri when dropped onto a map canvas.

The base class implementation returns False regardless of mime data.

This method is called when mime data is dragged over a map canvas, in order to determine whether any handlers are capable of handling the data and to determine whether the drag action should be accepted.

Warning

Subclasses should be very careful about implementing this. If they incorrectly return True to a uri, it will prevent the default application drop handling from occurring and will break the ability to drag and drop layers and files onto QGIS.

New in version 3.10.

Parameters
Return type

bool

canHandleMimeData(self, data: QMimeData) → bool

Returns True if the handler is capable of handling the provided mime data. The base class implementation returns False regardless of mime data.

This method is called when mime data is dragged over the QGIS window, in order to determine whether any handlers are capable of handling the data and to determine whether the drag action should be accepted.

New in version 3.10.

Parameters

data (QMimeData) –

Return type

bool

childEvent()
connectNotify()
customEvent()
customUriProviderKey(self) → str

Type of custom URI recognized by the handler. This must match the URI entry’s providerKey in order for handleCustomUriDrop() to be called.

Return type

str

disconnectNotify()
handleCustomUriCanvasDrop(self, uri: QgsMimeDataUtils.Uri, canvas: QgsMapCanvas) → bool

Called from QGIS after a drop event with custom uri known by the handler occurs onto a map canvas.

In order for handleCustomUriCanvasDrop() to be called, subclasses must also implement customUriProviderKey() to indicate the providerKey value which the handler accepts.

If the function returns True, it means the handler has accepted the drop and it should not be further processed (e.g. by other QgsCustomDropHandlers).

Subclasses which implement this must also implement corresponding versions of canHandleCustomUriCanvasDrop().

New in version 3.10.

Parameters
Return type

bool

handleCustomUriDrop(self, uri: QgsMimeDataUtils.Uri)

Called from QGIS after a drop event with custom URI known by the handler.

In order for handleCustomUriDrop() to be called, subclasses must also implement customUriProviderKey() to indicate the providerKey value which the handler accepts.

Parameters

uri (QgsMimeDataUtils.Uri) –

handleFileDrop(self, file: str) → bool

Called when the specified file has been dropped onto QGIS. If True is returned, then the handler has accepted this file and it should not be further processed (e.g. by other QgsCustomDropHandlers).

The base class implementation does nothing.

This method is not called directly while drop handling is occurring, so the limitations described in handleMimeData() about returning quickly do not apply.

Parameters

file (str) –

Return type

bool

handleMimeData(self, data: QMimeData)

Called when the specified mime data has been dropped onto QGIS.

The base class implementation does nothing.

Subclasses should take care when overriding this method. When a drop event occurs, Qt will lock the source application of the drag for the duration of the drop event handling (e.g. dragging files from explorer to QGIS will lock the explorer window until the drop handling has been complete).

Accordingly, only implementations must be lightweight and return ASAP. (For instance by copying the relevant parts of data and then handling the data after a short timeout).

Deprecated since version QGIS: 3.10 - use handleMimeDataV2() instead.

Parameters

data (QMimeData) –

handleMimeDataV2(self, data: QMimeData) → bool

Called when the specified mime data has been dropped onto QGIS.

The base class implementation does nothing.

Subclasses should take care when overriding this method. When a drop event occurs, Qt will lock the source application of the drag for the duration of the drop event handling (e.g. dragging files from explorer to QGIS will lock the explorer window until the drop handling has been complete).

Accordingly, only implementations must be lightweight and return ASAP. (For instance by copying the relevant parts of data and then handling the data after a short timeout).

If the function returns True, it means the handler has accepted the drop and it should not be further processed (e.g. by other QgsCustomDropHandlers)

New in version 3.10.

Parameters

data (QMimeData) –

Return type

bool

isSignalConnected()
receivers()
sender()
senderSignalIndex()
timerEvent()