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e0321be23f
and logic for activating a custom map tool and ensuring it can
only be enabled in the right circumstances to QGIS app
If a plugin has to do this, it's a nightmare of code and hacks (partly
because of the number of changing circumstances it needs to respond
to, and partly because a lot of the useful functions available
for handling this behavior is locked away in private methods
in qgisapp.cpp)
So instead make an abstract base class for map tool handlers and
an iface method for register/unregistering them.
From the dox:
An abstract base class for map tool handlers which automatically handle all the necessary
logic for toggling the map tool and enabling/disabling the associated action
when the QGIS application is in a state permissible for the tool.
Creating these handlers avoids a lot of complex setup code and manual connections
which are otherwise necessary to ensure that a map tool is correctly activated and
deactivated when the state of the QGIS application changes (e.g. when the active
layer is changed, when edit modes are toggled, when other map tools are switched
to, etc).
- ### Example
\code{.py}
class MyMapTool(QgsMapTool):
...
class MyMapToolHandler(QgsAbstractMapToolHandler):
def __init__(self, tool, action):
super().__init__(tool, action)
def isCompatibleWithLayer(self, layer, context):
# this tool can only be activated when an editable vector layer is selected
return isinstance(layer, QgsVectorLayer) and layer.isEditable()
my_tool = MyMapTool()
my_action = QAction('My Map Tool')
my_handler = MyMapToolHandler(my_tool, my_action)
iface.registerMapToolHandler(my_handler)
\endcode
116 lines
3.8 KiB
Plaintext
116 lines
3.8 KiB
Plaintext
/************************************************************************
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* This file has been generated automatically from *
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* *
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* src/gui/qgsabstractmaptoolhandler.h *
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* *
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* Do not edit manually ! Edit header and run scripts/sipify.pl again *
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************************************************************************/
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class QgsAbstractMapToolHandler
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{
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%Docstring
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An abstract base class for map tool handlers which automatically handle all the necessary
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logic for toggling the map tool and enabling/disabling the associated action
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when the QGIS application is in a state permissible for the tool.
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Creating these handlers avoids a lot of complex setup code and manual connections
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which are otherwise necessary to ensure that a map tool is correctly activated and
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deactivated when the state of the QGIS application changes (e.g. when the active
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layer is changed, when edit modes are toggled, when other map tools are switched
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to, etc).
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- ### Example
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.. code-block:: python
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class MyMapTool(QgsMapTool):
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...
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class MyMapToolHandler(QgsAbstractMapToolHandler):
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def __init__(self, tool, action):
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super().__init__(tool, action)
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def isCompatibleWithLayer(self, layer, context):
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# this tool can only be activated when an editable vector layer is selected
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return isinstance(layer, QgsVectorLayer) and layer.isEditable()
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my_tool = MyMapTool()
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my_action = QAction('My Map Tool')
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my_handler = MyMapToolHandler(my_tool, my_action)
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iface.registerMapToolHandler(my_handler)
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.. versionadded:: 3.16
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%End
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%TypeHeaderCode
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#include "qgsabstractmaptoolhandler.h"
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%End
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public:
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struct Context
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{
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bool dummy;
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};
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QgsAbstractMapToolHandler( QgsMapTool *tool, QAction *action );
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%Docstring
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Constructor for a map tool handler for the specified ``tool``.
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The ``action`` argument must be set to the action associated with switching
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to the tool.
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The ownership of neither ``tool`` nor ``action`` is transferred, and the caller
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is responsible for ensuring that these objects exist for the lifetime of the
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handler.
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.. warning::
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The handler will be responsible for creating the appropriate
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connections between the ``action`` and the ``tool``. These should NOT be
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manually connected elsewhere!
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%End
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virtual ~QgsAbstractMapToolHandler();
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QgsMapTool *mapTool();
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%Docstring
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Returns the tool associated with this handler.
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%End
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QAction *action();
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%Docstring
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Returns the action associated with toggling the tool.
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%End
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virtual bool isCompatibleWithLayer( QgsMapLayer *layer, const QgsAbstractMapToolHandler::Context &context ) = 0;
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%Docstring
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Returns ``True`` if the associated map tool is compatible with the specified ``layer``.
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Additional information is available through the ``context`` argument.
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%End
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virtual void setLayerForTool( QgsMapLayer *layer );
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%Docstring
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Sets the ``layer`` to use for the tool.
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Called whenever a new layer should be associated with the tool, e.g. as a result of the
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user selecting a different active layer.
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The default implementation does nothing.
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%End
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};
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/************************************************************************
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* This file has been generated automatically from *
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* *
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* src/gui/qgsabstractmaptoolhandler.h *
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* *
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* Do not edit manually ! Edit header and run scripts/sipify.pl again *
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************************************************************************/
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