Iphone 基于iOS4和部署iOS3的媒体播放器存在问题

在设备3.1.2上运行时，为什么还要传递if（NSClassFromString（@“MPMoviePlayerServiceWController”）！=nil 而iOS4的代码会崩溃吗，如何解决这个问题

               if(NSClassFromString(@"MPMoviePlayerViewController") != nil) {
                    // iOS 4 code
                    NSLog(@"MPMoviePlayerViewController");
                    MPMoviePlayerViewController *mp = [[MPMoviePlayerViewController alloc] initWithContentURL:[NSURL URLWithString:AppDelegate.PushLink]];
                    if (mp) {
                        // save the movie player object
                        self.theMovie4 = mp;
                        [mp release];
                        //Present                       
                        [self presentMoviePlayerViewControllerAnimated:self.theMovie4];

                        // Play the movie!
                        self.theMovie4.moviePlayer.movieSourceType = MPMovieSourceTypeStreaming;
                        [self.theMovie4.moviePlayer play];
                    }
                }
                else {
                    //iOS 3 Code
                    AppDelegate = nil;
                    AppDelegate = [[UIApplication sharedApplication] delegate];
                    [AppDelegate ForceHideNavigationBar];
                    theMovie3 = nil;

                    [[NSNotificationCenter defaultCenter] addObserver:self 
                                                             selector:@selector(moviePreloadDidFinish:) 
                                                                 name:MPMoviePlayerContentPreloadDidFinishNotification 
                                                               object:theMovie3];

                    [[NSNotificationCenter defaultCenter] addObserver:self 
                                                             selector:@selector(moviePlayBackDidFinish:) 
                                                                 name:MPMoviePlayerPlaybackDidFinishNotification 
                                                               object:theMovie3];

                    // Register to receive a notification when the movie scaling mode has changed. 
                    [[NSNotificationCenter defaultCenter] addObserver:self 
                                                             selector:@selector(movieScalingModeDidChange:) 
                                                                 name:MPMoviePlayerScalingModeDidChangeNotification 
                                                               object:theMovie3];

                    theMovie3 = [[MPMoviePlayerController alloc] initWithContentURL: [NSURL URLWithString:AppDelegate.PushLink]];

                    [theMovie3 play];

                }

---

我在我的应用程序上做了一件非常类似的事情，它使用4.0作为基本SDK，但我也瞄准了iOS3设备。我必须检查操作系统版本，以便为视频播放提供正确的代码。例如：

- (void) playMovieAtURL: (NSURL*) theURL {
    NSLog(@"playMovieAtURL");

if ([[[UIDevice currentDevice] systemVersion] doubleValue] >= 3.2) {
            NSLog(@"> 3.2");
            MPMoviePlayerViewController *mp = [[MPMoviePlayerViewController alloc] initWithContentURL:theURL];

            if (mp)
            {
                // save the movie player object
                //self.moviePlayerViewController = mp;
                //[mp release];
                [self presentMoviePlayerViewControllerAnimated:mp];
                mp.moviePlayer.movieSourceType = MPMovieSourceTypeFile;
                [mp.moviePlayer play];
                [mp release];
            }

        } 
    else if ([[[UIDevice currentDevice] systemVersion] doubleValue] < 3.2) {
            NSLog(@"< 3.2");

            MPMoviePlayerController* theMovie = [[MPMoviePlayerController alloc] initWithContentURL: theURL];

            theMovie.scalingMode = MPMovieScalingModeAspectFill;

            // Register for the playback finished notification
            [[NSNotificationCenter defaultCenter]
             addObserver: self
             selector: @selector(myMovieFinishedCallback:)
             name: MPMoviePlayerPlaybackDidFinishNotification
             object: theMovie];

            // Movie playback is asynchronous, so this method returns immediately.
            [theMovie play];



        }

    }

-（无效）播放电影自然：（NSURL*）URL{
NSLog（“Playmovieatural”）；
如果（[[[UIDevice currentDevice]systemVersion]doubleValue]>=3.2）{
NSLog（@“>3.2”）；
mpmovieplayervewcontroller*mp=[[mpmovieplayervewcontroller alloc]initWithContentURL:theURL]；
if（mp）
{
//保存电影播放器对象
//self.movieplayervewcontroller=mp；
//[mp发布]；
[自我呈现的电影播放服务控制器：mp]；
mp.moviePlayer.movieSourceType=mpmoviesourcetype文件；
[mp.moviePlayer play]；
[mp发布]；
}
} 
如果（[[[UIDevice currentDevice]systemVersion]doubleValue]<3.2），则为else{
NSLog（@“<3.2”）；
MPMoviePlayerController*theMovie=[[MPMoviePlayerController alloc]initWithContentURL:theURL]；
movie.scalingMode=MPMovieScalingModeAspectFill；
//注册播放完成通知
[[NSNotificationCenter defaultCenter]
addObserver:self
选择器：@selector（myMovieFinishedCallback:）
名称：MPMoviePlayerPlaybackDidFinishNotification
对象：theMovie]；
//电影播放是异步的，因此此方法立即返回。
[电影剧]；
}
}

希望这有帮助

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(moviePlayBackDidFinish:) 
        name:MPMoviePlayerPlaybackDidFinishNotification object:nil];

  NSString *movpath = [[NSBundle mainBundle] pathForResource:@"splash" ofType:@"mp4"];
  MPMoviePlayerViewController* mpviewController = [[MPMoviePlayerViewController alloc] 
                      initWithContentURL:[NSURL fileURLWithPath:movpath]];
  [window addSubview:mpviewController.view];
        [window makeKeyAndVisible];
  MPMoviePlayerController *mp = [mpviewController moviePlayer];
  [mp prepareToPlay];
  [[mpviewController moviePlayer] play];

此代码将在iOS4中工作

---

但是，它会在电影完成后退出，因为您必须为通知创建方法。您还需要在那里发布电影，以便捕获内存泄漏。

这是一个巨大的帮助。谢谢你，斯蒂兹！谢谢！它救了我一天！