mp3_player | A simple mp3 player plugin for rails

I am unable to understand and unable to solve a tkinter.TclError in this following code that i have written till now. Pls solve this question i have got homework to make a mp3 player program using python and i want Submitted it quickly. And also conivence i have given the tracback also. Code

I found this code from a YouTube tutorial produced by Adam Khoury from his Analyser Bars Animation HTML5 Audio API JavaScript Tutorial. Where a music analyser graphic reacts to a sound file It is from 2013. I have tried to get it to work by updating the code as far as I understand it. I have removed webkit and adjusted the syntax changing some letters to lowercase. It plays fine in the Edge browser but not in Chrome. Obviously, I have missed something, any help would be greatly appreciated.

HTML code:

I am implementing "BaseActivity" that contain toolbar for all other activities. this base activity need to be extends in other activity to add toolbar. Now problem is I am having one activity named "ElectronicsMainActivity" having listview in it. This activity need to extends "BaseActivity" like

public class ElectronicsMainActivity extends BaseActivity{

But my app is getting crashed at runtime when starting this activity.

error is:

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference

My "ElectronicsMainActivity" code is:

So i followed this tutorial: https://youtu.be/IBHpSkGZtNM And a while back (about a year ago or so) it worked. Now however it doesn't visualize anything. The sound plays but thats it.

I changed the old webkit functions to the new ones as i was getting errors. However now i don't have any errors and still nothing shows up.

Here is my code:

I'm trying to build a mock-up audio visual analyser using requestAnimationFrame and canvas. My setup is building an analyser constructor, load audio source etc into it. I have a canvas draw function that is attached to Array of numbers updating as requestAnimationFrame runs. I'd like to be able to toggle that animation on/off with music play/pause button.

I have tried making a custom button that toggles music on/off and a variable that keeps track of isPlaying state but can't successfully attach it to animation function. https://jsfiddle.net/kshatriiya/p8u5h3dz/6/ I can't find a suitable mp3 source online so please place a source at object creation at the end.