Trying to create an addin but the UnboundLocalError problem persist

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02-28-2015 03:38 PM
PROBERT68
Frequent Contributor
import arcpy
import pythonaddins


class ToolClassRandom(object):
    """Implementation for GenerateRandomPoints_addin.tool (Tool)"""
    def __init__(self):
        self.enabled = True
        self.cursor = 3
        self.shape = 'Rectangle' # Can set to "Line", "Circle" or "Rectangle" for interactive shape drawing and to activate the onLine/Polygon/Circle event sinks.
    def onMouseDown(self, x, y, button, shift):
        pass
    def onMouseDownMap(self, x, y, button, shift):
        pass
    def onMouseUp(self, x, y, button, shift):
        pass
    def onMouseUpMap(self, x, y, button, shift):
        pass
    def onMouseMove(self, x, y, button, shift):
        pass
    def onMouseMoveMap(self, x, y, button, shift):
        pass
    def onDblClick(self):
        pass
    def onKeyDown(self, keycode, shift):
        pass
    def onKeyUp(self, keycode, shift):
        pass
    def deactivate(self):
        pass
    def onCircle(self, circle_geometry):
        pass
    def onLine(self, line_geometry):
        pass
    def onRectangle(self, rectangle_geometry):
        extent = rectangle_geometry
        arcpy.env.workspace = "c:\ArcpyBook\Ch11"
        if arcpy.Exists("randompts.shp"):
            arcpy.Delete_management("randompts.shp")
            randompts = arcpy.CreateRandomPoints_management(arcpy.env.workspace,"randompts","randompts.shp","POINT",rectangle_geometry)
            arcpy.RefreshActiveView()
        return randompts

Been trying to run this code  to create an addin for the Generate Random Points. It gave me the error that says:

Traceback (most recent call last):

  File "C:\Users\Pollock\AppData\Local\ESRI\Desktop10.1\AssemblyCache\{A6309427-3034-2E61-07C7-2A592C101F22}\GenerateRandomPoints_addin.py", line 41, in onRectangle

    return randompts

UnboundLocalError: local variable 'randompts' referenced before assignment

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1 Solution

Accepted Solutions
Luke_Pinner
MVP Regular Contributor

What do you mean "not working"?

The following works for me:

    def onRectangle(self, rectangle_geometry):  
        arcpy.env.workspace = r"IN_MEMORY"
        arcpy.env.overwriteOutput = True
        lyrname = 'randompts'
        randompts = arcpy.CreateRandomPoints_management(arcpy.env.workspace,lyrname,'',rectangle_geometry).getOutput(0)
        
        mxd=arcpy.mapping.MapDocument('CURRENT')
        adf = mxd.activeDataFrame
        
        try:
            lyr=arcpy.mapping.ListLayers(mxd, lyrname, adf)[0]
        except IndexError:
            lyr=arcpy.MakeFeatureLayer_management(randompts, lyrname).getOutput(0)
            arcpy.mapping.AddLayer(adf,lyr)
            lyr=arcpy.mapping.ListLayers(mxd, lyrname, adf)[0]

        arcpy.RefreshActiveView()

View solution in original post

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6 Replies
XanderBakker
Esri Esteemed Contributor

The third parameter of the line:

randompts = arcpy.CreateRandomPoints_management(arcpy.env.workspace,"randompts","randompts.shp","POINT",rectangle_geometry)

... refers to the "constraining_feature_class" (Optional).

Random points will be generated inside or along the features in this feature class.

This featureclass should exist, but you just deleted it...

PROBERT68
Frequent Contributor

You mean I just deleted was because of the same name ? I am still struggled with it and trying to do many different method even I looked at the CreateRandomPoints help on arcgis 10.1.

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Luke_Pinner
MVP Regular Contributor

If the shapefile doesn't exist, the "randompts = arcpy.CreateRandomPoints_management" line will never get called, so when you "return randompts", the randompts variable has not been defined and you will get the UnboundLocalError.

Do this instead:

def onRectangle(self, rectangle_geometry): 
    extent = rectangle_geometry 
    arcpy.env.workspace = "c:\ArcpyBook\Ch11" 
    if arcpy.Exists("randompts.shp"): 
        arcpy.Delete_management("randompts.shp") 
    randompts = arcpy.CreateRandomPoints_management(arcpy.env.workspace,"randompts","randompts.shp","POINT",rectangle_geometry) 
    arcpy.RefreshActiveView() 
    return randompts
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PROBERT68
Frequent Contributor

Thanks. It is still not working though I do believe the Delete management had to do with it.

What I did was drag around a boundary and nothing comes out..so I modifty to see what happens and

this only works...

so I put number sign next to 04 and 05 . See here:

def onRectangle(self, rectangle_geometry):
        extent = rectangle_geometry
        arcpy.env.workspace = r"c:\ArcpyBook\Ch11"
        #if arcpy.Exists('randompts.shp'):
            #arcpy.Delete_management('randompts.shp')
        randompts = arcpy.CreateRandomPoints_management(arcpy.env.workspace,'randompts.shp',"",rectangle_geometry)
        arcpy.RefreshActiveView()
        #return randompts
        pass

This was from the book I have on page 231 from Programming ArcGIS 10.1 with Python cookbook. I know probably it has change since then. The book was published in 2013.

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Luke_Pinner
MVP Regular Contributor

What do you mean "not working"?

The following works for me:

    def onRectangle(self, rectangle_geometry):  
        arcpy.env.workspace = r"IN_MEMORY"
        arcpy.env.overwriteOutput = True
        lyrname = 'randompts'
        randompts = arcpy.CreateRandomPoints_management(arcpy.env.workspace,lyrname,'',rectangle_geometry).getOutput(0)
        
        mxd=arcpy.mapping.MapDocument('CURRENT')
        adf = mxd.activeDataFrame
        
        try:
            lyr=arcpy.mapping.ListLayers(mxd, lyrname, adf)[0]
        except IndexError:
            lyr=arcpy.MakeFeatureLayer_management(randompts, lyrname).getOutput(0)
            arcpy.mapping.AddLayer(adf,lyr)
            lyr=arcpy.mapping.ListLayers(mxd, lyrname, adf)[0]

        arcpy.RefreshActiveView()
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PROBERT68
Frequent Contributor

That code you provide worked ! Thanks !

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