MPMoviePlayerController not working in iOS4

I'm using the first answer from iOS 4 + MPMoviePlayerController

to try and get MPMoviePlayerController to play. In the simulator (iPhone device with iOS4), I hear sound but no video. On the device (iPhone 3GS and iOS4), I don't get anything. Here's my code:

    MPMoviePlayerController *开发者_运维技巧moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:[NSURL fileURLWithPath:moviePath]];
    moviePlayer.movieControlMode = MPMovieControlModeDefault;

    if ([moviePlayer respondsToSelector:@selector(view)]) {
        moviePlayer.controlStyle = MPMovieControlStyleFullscreen;
        [moviePlayer.view setFrame:self.view.bounds];
        [self.view addSubview:moviePlayer.view];
    }

    [moviePlayer play];

Any ideas what I'm doing wrong?

I just tested the following code on iOS4 + iPhone 4 (and a 3GS)—it works fine. At first blush, I think your code's problem is not calling setFullscreen:animated on your MPMoviePlayerController instance.

- (void)willEnterFullscreen:(NSNotification*)notification {
    NSLog(@"willEnterFullscreen");
}

- (void)enteredFullscreen:(NSNotification*)notification {
    NSLog(@"enteredFullscreen");
}

- (void)willExitFullscreen:(NSNotification*)notification {
    NSLog(@"willExitFullscreen");
}

- (void)exitedFullscreen:(NSNotification*)notification {
    NSLog(@"exitedFullscreen");
    [self.movieController.view removeFromSuperview];
    self.movieController = nil;
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

- (void)playbackFinished:(NSNotification*)notification {
    NSNumber* reason = [[notification userInfo] objectForKey:MPMoviePlayerPlaybackDidFinishReasonUserInfoKey];
    switch ([reason intValue]) {
        case MPMovieFinishReasonPlaybackEnded:
            NSLog(@"playbackFinished. Reason: Playback Ended");         
            break;
        case MPMovieFinishReasonPlaybackError:
            NSLog(@"playbackFinished. Reason: Playback Error");
            break;
            case MPMovieFinishReasonUserExited:
            NSLog(@"playbackFinished. Reason: User Exited");
            break;
        default:
            break;
    }
    [self.movieController setFullscreen:NO animated:YES];
}

- (void)showMovie {
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(willEnterFullscreen:) name:MPMoviePlayerWillEnterFullscreenNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(willExitFullscreen:) name:MPMoviePlayerWillExitFullscreenNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(enteredFullscreen:) name:MPMoviePlayerDidEnterFullscreenNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(exitedFullscreen:) name:MPMoviePlayerDidExitFullscreenNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playbackFinished:) name:MPMoviePlayerPlaybackDidFinishNotification object:nil];

    NSURL* movieURL =  [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"tron" ofType:@"mov"]];
    self.movieController = [[MPMoviePlayerController alloc] initWithContentURL:movieURL];
    if ([self.movieController respondsToSelector:@selector(view)]) {
        self.movieController.view.frame = self.view.frame;
        [self.view addSubview:movieController.view];
        [self.movieController setFullscreen:YES animated:YES];
    }
    [self.movieController play];
}

// This method is set as the action for an on-screen button
- (void)movieTime:(id)sender {
    [self showMovie];
}

For MPMoviePlayerController view is a property, not a method, so you can't use respondsToSelector: on it if it doesn't have methods synthesized or written for it (i.e. is declared @dynamic). Which I think is true for most readonly properties in UIKit.