FirstApp，iphone开发学习总结12，播放音乐、视频

添加AVFoundation.framework 和MediaPlayer.framework。

在NavView.h文件中，添加：

#import <AVFoundation/AVFoundation.h>
#import <MediaPlayer/MediaPlayer.h>

@interface NavView1 : UIViewController<AVAudioPlayerDelegate>{
    AVAudioPlayer *audioPlayer;
    MPMoviePlayerController *moviePlayer;
}
@end

 在init中添加音乐url：

- ( id)init {
    self = [super init];
     if (self) {
         // ...
        NSString *musicPath = [[NSBundle mainBundle] pathForResource: @" yu " ofType: @" mp3 "];
         if (musicPath) {
            NSURL *musicURL = [NSURL fileURLWithPath:musicPath];
            audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:musicURL error:nil];
            [audioPlayer setDelegate:self];
        }
    }
     return self;
}

 在view中添加2个按钮：

- ( void)viewDidLoad
{
     // ...
    UIButton *musicPlayBtn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    musicPlayBtn.frame = CGRectMake( 40.0,  70.0,  240.0,  30.0);
    [musicPlayBtn setTitle: @" Play Music " forState:UIControlStateNormal];
    [musicPlayBtn addTarget:self action:@selector(playMusic:) forControlEvents:UIControlEventTouchUpInside];
    
    UIButton *movePlayBtn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    movePlayBtn.frame = CGRectMake( 40.0,  110.0,  240.0,  30.0);
    [movePlayBtn setTitle: @" Play Move " forState:UIControlStateNormal];
    [movePlayBtn addTarget:self action:@selector(playMovie:) forControlEvents:UIControlEventTouchUpInside];

     // ...
    [[self view] addSubview:musicPlayBtn];
    [[self view] addSubview:movePlayBtn];
}

 播放音乐按钮实现：//退出后，再进入，音乐接着播放，按钮变为play，需要解决方案。

- ( void)playMusic:( id)sender
{
     if ([audioPlayer isPlaying]) {
        [audioPlayer stop];
        [sender setTitle: @" Play Music " forState:UIControlStateNormal];
    }
     else
    {
        [audioPlayer play];
        [sender setTitle: @" Stop Music " forState:UIControlStateNormal];
    }
}

 视频播放：

- ( void)playMovie:( id)sender
{
    NSString *moviePath = [[NSBundle mainBundle] pathForResource: @" big " ofType: @" m4v "];
     if (moviePath) {
        NSURL *movieURL = [NSURL fileURLWithPath:moviePath];
        moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:movieURL];
    }
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(stopMoviePlay:) name:MPMoviePlayerPlaybackDidFinishNotification  object:moviePlayer];
    moviePlayer.view.frame = CGRectMake( 40.0,  150.0,  240.0,  140.0); //播放完成
    [[self view] addSubview:[moviePlayer view]];
}

 //添加通知，当视频播放完成，从view移除

- ( void)stopMoviePlay:( id)sender
{
    MPMoviePlayerController *mp = [sender  object];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:MPMoviePlayerPlaybackDidFinishNotification  object:mp];
    [[moviePlayer view] removeFromSuperview];
}

打开FirstApp-Info.plist文件，添加Required background modes，设置item0值为App plays audio。支持音乐后台播放。（模拟器不支持）