何らかの理由でsetcurrentPlaybackメソッドが機能しません。ご意見ありがとうございます...
-(IBAction)abspielen:(id)sender {
NSString *titleOfButton = [sender titleForState:UIControlStateNormal];
NSBundle *bundle = [NSBundle mainBundle];
NSString *moviePath = [bundle pathForResource:titleOfButton ofType:@"mov"];
NSURL *movieURL = [ NSURL fileURLWithPath:moviePath];
MPMoviePlayerController *themovie =
[[MPMoviePlayerController alloc]initWithContentURL: movieURL];
[themovie play];
[themovie setCurrentPlaybackRate:2.f];
[themovie release];
MPMoviePlayerViewController *moviePlayer =
[[MPMoviePlayerViewController alloc] initWithContentURL:movieURL];
[self presentMoviePlayerViewControllerAnimated:moviePlayer];
[moviePlayer release];
}