pygame中的screen.blit（image），图像消失

Question

I'm trying to blit an image in a pygame window based on one event, a midi input, and then blit another image based on the next event, another midi input. What happens here is that the image pops up just for a second when I press a key on the midi keyboard. I need it to stay in the window, even after I enter another input and blit another image. What happens with this is that each key on my midi keyboard gets recorded as a number (1-88) and added to NoteList[] then an image is blit in the window using h , an item in NoteList as the x coordinate. In my actual pygame the h variable will also go through a bunch of functions, I am just trying to figure out this part in a simpler pygame window.

going = True
while going:
    screen.fill(white)
    events = event_get()
    NoteList=[]
    for e in events:
        if e.type in [QUIT]:
            going = False
        if e.type in [KEYDOWN]:
            going = False
            events = pygame.event.get()
        if e.type in [pygame.midi.MIDIIN]:
            print(str(e.data1))
            NoteList.append(int(e.data1-20))
    for h in NoteList:
            screen.blit(EthnoteIMG, (int(h), 100))
    pygame.display.update()

Answer 1

I belive that the problem is that you fill the screen every time the while loop runs but you just blit that image on the screen when the event occurs...

Try this:

screen.fill(white)
going = True
while going:
    events = event_get()
    NoteList=[]
    for e in events:
        if e.type in [QUIT]:
            going = False
        if e.type in [KEYDOWN]:
            going = False
            events = pygame.event.get()
        if e.type in [pygame.midi.MIDIIN]:
            print(str(e.data1))
            NoteList.append(int(e.data1-20))
    for h in NoteList:
        screen.fill(white)
        screen.blit(EthnoteIMG, (int(h), 100))
    pygame.display.update()

Answer 2

You need to define the NoteList outside of the while loop if the notes should persist, otherwise you create a new empty list each iteration.

NoteList = []

going = True
while going:
    for e in pygame.event.get():
        if e.type == pygame.QUIT:
            going = False
        elif e.type == pygame.midi.MIDIIN:
            print(str(e.data1))
            NoteList.append(int(e.data1-20))

    screen.fill(white)

    for h in NoteList:
        screen.blit(EthnoteIMG, (int(h), 100))

    pygame.display.update()

---

You can use the enumerate function to shift the position:

for g, h in enumerate(NoteList):
    screen.blit(EthnoteIMG, (g*12, int(h)))