Multiple files can now be loaded. Fixed GUI becoming unresponsive while a song is playing.

main.py

@@ -25,8 +25,10 @@
 from tkinter import *
 from tkinter import ttk
 from tkinter import filedialog as fd
+from tkinter import messagebox as mb
 import subprocess as sp
 import os
+import threading
 
 class MidiPort:
     
@@ -45,6 +47,11 @@ class App(ttk.Frame):
         self.devices = self.get_midi_list()
         self.create_widgets()
         self.midi_port_var.set(str(self.devices[0]))
+        # play control
+        self.play_mutex = threading.Lock()
+        self.is_playing = False
+        self.stop_after = False
+        self.files = ()
         
     def create_widgets(self):
         self.midi_port_label = ttk.Label(self, text="Midi Device")
@@ -58,16 +65,24 @@ class App(ttk.Frame):
         self.midi_file_label = ttk.Label(self, text="File")
         self.midi_file_label.grid(column=0, row=1)
         self.midi_file_var = StringVar()
-        self.midi_file_text = ttk.Entry(self, textvariable=self.midi_file_var, width=80)
+        self.midi_file_text = Listbox(self, listvariable=self.midi_file_var, width=80, height=20, selectmode="extended")
         self.midi_file_text.grid(column=1, row=1)
         self.midi_file_button = ttk.Button(self,
                                            text="Open...",
-                                           command=lambda: self.midi_file_var.set(fd.askopenfilename(defaultextension=".mid", filetypes=[("MIDI", ".mid")], initialdir=os.environ['HOME'])))
-        self.midi_file_button.grid(column=2, row=1, sticky=(E, W))
+                                           command=self.open_file)
+        self.midi_file_button.grid(column=3, row=1, sticky=(E, W))
+        self.midi_file_scroll = ttk.Scrollbar(self, orient=VERTICAL, command=self.midi_file_text.yview)
+        self.midi_file_text.configure(yscrollcommand=self.midi_file_scroll.set)
+        self.midi_file_scroll.grid(column=2, row=1, sticky=(N, S, W))
         
         self.play_button = ttk.Button(self, text="Play", command=self.play_midi)
         self.play_button.grid(column=1, row=2)
         
+        self.stop_after_var = StringVar()
+        self.stop_after_var.set("go")
+        self.stop_after_button = ttk.Checkbutton(self, text="Stop after current", command=self.stop_after_current, variable=self.stop_after_var, onvalue="stop", offvalue="go")
+        self.stop_after_button.grid(column=2, row=2, columnspan=2)
+        
         self.columnconfigure(1, weight=1)
 
     @staticmethod
@@ -79,14 +94,46 @@ class App(ttk.Frame):
         port_name_start = devices[0].find("Port name")
         return [MidiPort(i[port_start:client_name_start].strip(), i[client_name_start:port_name_start].strip(), i[port_name_start:].strip()) for i in devices[1:]]
         
+    def stop_after_current(self):
+        self.play_mutex.acquire()
+        self.stop_after = self.stop_after_var.get() == "stop"
+        self.play_mutex.release()
+        
     def play_midi(self):
-        sp.run(["aplaymidi", "-p", self.devices[self.midi_port_selector.current()].port, self.midi_file_var.get()])
+        self.play_mutex.acquire()
+        if self.is_playing:
+            self.play_mutex.release()
+            mb.showinfo(message="Another song cannot play until the previous song is finished playing.")
+        else:
+            self.play_mutex.release()
+            port = self.devices[self.midi_port_selector.current()].port
+            midis = [self.files[f] for f in self.midi_file_text.curselection()]
+            if len(midis) == 0:
+                midis = self.files
+            play_thread = threading.Thread(target=self.play_thread, args=(port, midis))
+            play_thread.start()
+        
+    def play_thread(self, port: str, midis: list):
+        self.play_mutex.acquire()
+        self.is_playing = True
+        self.play_mutex.release()
+        for midi in midis:
+            sp.run(["aplaymidi", "-p", port, midi])
+            self.play_mutex.acquire()
+            if self.stop_after:
+                self.play_mutex.release()
+                break;
+            self.play_mutex.release()
+        self.play_mutex.acquire()
+        self.is_playing = False
+        self.play_mutex.release()
         
     def open_file(self):
-        initial_dir = os.pwd()
+        initial_dir = os.getcwd()
         if 'HOME' in os.environ:
             initial_dir = os.environ['HOME']
-        self.midi_file_var.set(fd.askopenfilename(defaultextension=".mid", filetypes=[("MIDI", ".mid")], initialdir=initial_dir))
+        self.files = fd.askopenfilename(defaultextension=".mid", filetypes=[("MIDI", ".mid")], initialdir=initial_dir, multiple=True)
+        self.midi_file_var.set(self.files)
 
 def main(args):
     root = Tk()