blender-blend-file-uiist example updated for Blender 2.9.3

blender-blend-file-uiist_2_9_3.py

import bpy
from bpy.props import IntProperty, CollectionProperty, StringProperty 
from bpy.types import Panel, UIList
from bpy_extras.io_utils import ImportHelper
import os
  
# ui list item actions
class Uilist_actions(bpy.types.Operator):
    bl_idname = "custom.list_action"
    bl_label = "List Action"

    action : bpy.props.EnumProperty(
        items=(
            ('UP', "Up", ""),
            ('DOWN', "Down", ""),
            ('REMOVE', "Remove", ""),
            ('ADD', "Add", ""),
        )
    )

    def invoke(self, context, event):

        scn = context.scene
        idx = scn.custom_index

        try:
            item = scn.custom[idx]
        except IndexError:
            pass

        else:
            if self.action == 'DOWN' and idx < len(scn.custom) - 1:
                item_next = scn.custom[idx+1].name
                scn.custom_index += 1
                info = 'Item %d selected' % (scn.custom_index + 1)
                self.report({'INFO'}, info)

            elif self.action == 'UP' and idx >= 1:
                item_prev = scn.custom[idx-1].name
                scn.custom_index -= 1
                info = 'Item %d selected' % (scn.custom_index + 1)
                self.report({'INFO'}, info)

            elif self.action == 'REMOVE':
                info = 'Item %s removed from list' % (scn.custom[scn.custom_index].name)
                scn.custom_index -= 1
                self.report({'INFO'}, info)
                scn.custom.remove(idx)

        if self.action == 'ADD':
            bpy.ops.custom.blend_select('INVOKE_DEFAULT')            
            scn.custom_index = (len(scn.custom)) # (len(scn.custom)-1)

        return {"FINISHED"}


class BlendSelectOperator(bpy.types.Operator, ImportHelper):
    """This appears in the tooltip of the operator and in the generated docs"""
    bl_idname = "custom.blend_select"
    bl_label = "Blend Selector"
    bl_options = {'PRESET', 'UNDO'}

    # ImportHelper mixin class uses this
    filename_ext = ".blend"

    filter_glob = StringProperty(
            default="*.blend",
            options={'HIDDEN'},
            )

    # Selected files
    files: CollectionProperty(type=bpy.types.PropertyGroup)

    def execute(self, context):
        scn = context.scene
        
        # get the folder
        folder = (os.path.dirname(self.filepath))

        # iterate through the selected files
        for j, i in enumerate(self.files):
            # generate full path to file
            path_to_file = (os.path.join(folder, i.name))   
            item = scn.custom.add()
            item.id = len(scn.custom)
            item.name = i.name # assign name of selected object
            item.path = path_to_file
        
        self.report({'INFO'}, "Files Added")
        return {'FINISHED'}
    
# -------------------------------------------------------------------
# draw
# -------------------------------------------------------------------

# custom list
class UL_items(UIList):

    def draw_item(self, context, layout, data, item, icon, active_data, active_propname, index):
        split = layout.split(factor=0.7)
        split.prop(item, "name", text="", emboss=False, translate=False, icon='FILE_BLEND')
        split.label(text="Index: %d" % (index))

    def invoke(self, context, event):
        pass   

# draw the panel
class UIListPanelExample(Panel):
    """Creates a Panel in the Object properties window"""
    bl_idname = 'OBJECT_PT_my_panel'
    bl_space_type = "TEXT_EDITOR"
    bl_region_type = "UI"
    bl_label = "Custom Blend File List"
    
    def draw(self, context):
        layout = self.layout
        scn = bpy.context.scene
        
        try:
            current_item = (scn.custom[scn.custom_index].name)
        except IndexError:
            current_item = ""
        
        #row.operator("custom.list_action", icon='ZOOMIN', text="Add Files").action = 'ADD'
        #row.operator("custom.list_action", icon='ZOOMOUT', text="").action = 'REMOVE'
        #split = row.split(align=True, percentage=0.6)
        
        rows = 2
        row = layout.row()
        row.template_list("UL_items", "", scn, "custom", scn, "custom_index", rows=rows)

        col = row.column(align=True)
        #col.operator("custom.list_action", icon='ZOOMIN', text="").action = 'ADD'
        #col.operator("custom.list_action", icon='ZOOMOUT', text="").action = 'REMOVE'
        #col.separator()
        col.operator("custom.list_action", icon='TRIA_UP', text="").action = 'UP'
        col.operator("custom.list_action", icon='TRIA_DOWN', text="").action = 'DOWN'
                
        row = layout.row()
        col = layout.column(align=True)
        rowsub = col.row(align=True)
        rowsub.operator("custom.list_action", icon='ZOOM_IN', text="Add Files to List").action = 'ADD'
        rowsub.operator("custom.list_action", icon='ZOOM_OUT', text="Remove File").action = 'REMOVE'
        
        
        row = layout.row()
        col = row.column(align=True)
        col.operator("custom.active_item", icon="CONSOLE")
        col.operator("custom.print_list", icon="WORDWRAP_ON")
        col.operator("custom.clear_list", icon="X")
        
        row = layout.row(align=True)
        row.label(text="Active Item is: {}".format(current_item))

# clear button
class Uilist_clearAllItems(bpy.types.Operator):
    bl_idname = "custom.clear_list"
    bl_label = "Clear List"
    bl_description = "Clear all items in the list"

    def execute(self, context):
        scn = context.scene
        lst = scn.custom
        current_index = scn.custom_index

        if len(lst) > 0:
             # reverse range to remove last item first
            for i in range(len(lst)-1,-1,-1):
                scn.custom.remove(i)
            self.report({'INFO'}, "All items removed")

        else:
            self.report({'INFO'}, "Nothing to remove")   

        return{'FINISHED'}

# print button
class Uilist_printAllItems(bpy.types.Operator):
    bl_idname = "custom.print_list"
    bl_label = "Print Name, ID and Path to Console"
    bl_description = "Print all items to the Console"

    def execute(self, context):
        scn = context.scene
        for i in scn.custom:
            print ("Blend-File:", i.name, "ID:", i.id, "Path:", i.path)
        
        return{'FINISHED'}

# select button
class Uilist_selectAllItems(bpy.types.Operator):
    bl_idname = "custom.active_item"
    bl_label = "Print Active Item to Console"
    bl_description = "Print Active Selection"

    def execute(self, context):
        scn = context.scene
        print (scn.custom[scn.custom_index].name)
        
        return{'FINISHED'}
    
# Create custom property group
class CustomProps(bpy.types.PropertyGroup):
    id = IntProperty()
    name = StringProperty()
    path = StringProperty()
    
# -------------------------------------------------------------------
# register
# -------------------------------------------------------------------

classes = (
    Uilist_actions,
    UL_items,
    BlendSelectOperator,
    UIListPanelExample,
    Uilist_clearAllItems,
    Uilist_printAllItems,        
    Uilist_selectAllItems,
    CustomProps,
)

def register():
    from bpy.utils import register_class
    for cls in classes:
        register_class(cls)
    bpy.types.Scene.custom = CollectionProperty(type=CustomProps)
    bpy.types.Scene.custom_index = IntProperty()


def unregister():
    from bpy.utils import unregister_class
    for cls in reversed(classes):
        unregister_class(cls)
    del bpy.types.Scene.custom
    del bpy.types.Scene.custom_index

if __name__ == "__main__":
    register()