Blender Crashes when i use Python Script

Question

I have a python script which works fine when I run in text editor. But I want to create Addon for that script. I am not from coding background so do not have much knowledge in python. I have seen a YouTube video (https://www.youtube.com/watch?v=Y67eCfiqJQU&ab_channel=chocofur) to create addon but it is not working Blender freezes as install the addon and Execute it as I have mentioned the code itself works fine. Here Is the Final code:

bl_info = {
    "name": "New_Object",
    "author": "Your Name Here",
    "version": (1, 0),
    "blender": (2, 80, 0),
    "location": "View3D > Add > Mesh > New Object",
    "description": "Adds a new Mesh Object",
    "warning": "",
    "doc_url": "",
    "category": "Add Mesh",
}


import bpy
import os

def main(context):


    target_dir = "C:/Users/Arpit/Desktop/UV/" 
    selObj = []

    for obj in bpy.context.selected_objects:
        selObj.append(obj.name)
        bpy.ops.object.select_all(action='TOGGLE')
        i=0
    while i < len(selObj):
        obj = bpy.context.window.scene.objects[0]
        bpy.context.view_layer.objects.active = obj
        bpy.ops.object.mode_set(mode="EDIT")
        bpy.ops.mesh.select_all(action='TOGGLE')
        bpy.ops.mesh.select_all(action='TOGGLE')
        full_file_name=target_dir + bpy.data.objects[selObj[i]].name
        dirname = os.path.dirname(full_file_name)
    if not os.path.exists(dirname):
        os.makedirs(dirname)
        bpy.ops.uv.export_layout(filepath=full_file_name, mode='PNG', size=(4096, 4096), opacity=0.6)
        bpy.ops.object.mode_set(mode="OBJECT")
        bpy.ops.object.select_all(action='TOGGLE')
        i+=1

class SimpleOperator(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "object.simple_operator"
    bl_label = "Simple Object Operator"


    def execute(self, context):
        main(context)
        return {'FINISHED'}

def menu_func(self, context):
    self.layout.operator(SimpleOperator.bl_idname, text=SimpleOperator.bl_label)





class LayoutDemoPanel(bpy.types.Panel):
    """Creates a Panel in the scene context of the properties editor"""
    bl_label = "Layout Demo"
    bl_idname = "SCENE_PT_layout"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "scene"

    def draw(self, context):
        layout = self.layout

        scene = context.scene


        # Big render button
        layout.label(text="Big Button:")
        row = layout.row()
        row.scale_y = 2.0
        row.operator("object.simple_operator")



def register():
    bpy.utils.register_class(LayoutDemoPanel)
    bpy.utils.register_class(SimpleOperator)
    bpy.types.VIEW3D_MT_object.append(menu_func)



def unregister():
    bpy.utils.unregister_class(LayoutDemoPanel)
    bpy.utils.unregister_class(SimpleOperator)
    bpy.types.VIEW3D_MT_object.remove(menu_func)


if __name__ == "__main__":
    register()

Please Guide me. Main code is under def main(context): Rest is the template

Answer 1

I can't run it but I see some mistakes with indentations - and this can make problem and code may run in endless loop and freeze program.

You put if in the same column as while so it finishs while-loop and rest is executed after exiting this loop. But this loop check i to exit and now you have i += 1 outside this loop so it never change this i.

If you change indentations then if will be inside loop and i += 1 will be also inside loop and this should resolve problem with freezing.

def main(context):

    target_dir = "C:/Users/Arpit/Desktop/UV/" 
    selObj = []

    for obj in bpy.context.selected_objects:
        selObj.append(obj.name)
        bpy.ops.object.select_all(action='TOGGLE')

    # --- while-loop ---
    
    i = 0

    while i < len(selObj):
        obj = bpy.context.window.scene.objects[0]
        bpy.context.view_layer.objects.active = obj
        bpy.ops.object.mode_set(mode="EDIT")
        bpy.ops.mesh.select_all(action='TOGGLE')
        bpy.ops.mesh.select_all(action='TOGGLE')
        full_file_name = target_dir + bpy.data.objects[selObj[i]].name
        dirname = os.path.dirname(full_file_name)

        # inside `while`-loop
        if not os.path.exists(dirname):
            os.makedirs(dirname)

        bpy.ops.uv.export_layout(filepath=full_file_name, mode='PNG', size=(4096, 4096), opacity=0.6)
        bpy.ops.object.mode_set(mode="OBJECT")
        bpy.ops.object.select_all(action='TOGGLE')

        i += 1

But frankly I would do it with for-loop and it wouldn't need i = 0, i += 1 and selObj[i] but only item

    # --- for-loop ---

    # without `i = 0`

    for item in selObj:

        obj = bpy.context.window.scene.objects[0]
        bpy.context.view_layer.objects.active = obj
        bpy.ops.object.mode_set(mode="EDIT")
        bpy.ops.mesh.select_all(action='TOGGLE')
        bpy.ops.mesh.select_all(action='TOGGLE')

        # `item` instead of `selObj[i]`
        full_file_name = target_dir + bpy.data.objects[ item ].name
        dirname = os.path.dirname(full_file_name)

        # inside `while`-loop
        if not os.path.exists(dirname):
            os.makedirs(dirname)

        bpy.ops.uv.export_layout(filepath=full_file_name, mode='PNG', size=(4096, 4096), opacity=0.6)
        bpy.ops.object.mode_set(mode="OBJECT")
        bpy.ops.object.select_all(action='TOGGLE')

        # without `i += 1`