iOS音视频学习6——MPMoviePlayerControll

在iOS中播放视频可以使用MediaPlayer.framework种的MPMoviePlayerController类来完成，它支持本地视频和网络视频播放。这个类实现了MPMediaPlayback协议，因此具备一般的播放器控制功能，例如播放、暂停、停止等。
但是MPMediaPlayerController自身并不是一个完整的视图控制器，如果要在UI中展示视频需要将view属性添加到界面中。下面列出了MPMoviePlayerController的常用属性和方法：

属性1 属性2 对象方法 通知

注意MPMediaPlayerController的状态等信息并不是通过代理来和外界交互的，而是通过通知中心，因此从上面的列表中可以看到常用的一些通知。

由于MPMoviePlayerController本身对于媒体播放做了深度的封装，使用起来就相当简单：
创建MPMoviePlayerController对象，设置frame属性，将MPMoviePlayerController的view添加到控制器视图中。下面的示例中将创建一个播放控制器并添加播放状态改变及播放完成的通知：

//
//  ViewController.m
//  MPMoviePlayerController
//
//  Created by Kenshin Cui on 14/03/30.
//  Copyright (c) 2014年 cmjstudio. All rights reserved.
//

#import "ViewController.h"
#import <MediaPlayer/MediaPlayer.h>
#import <AVKit/AVKit.h>


@interface ViewController ()

@property (nonatomic,strong) MPMoviePlayerController *moviePlayer;//视频播放控制器

@end

@implementation ViewController

#pragma mark - 控制器视图方法
- (void)viewDidLoad {
    [super viewDidLoad];
    
    //播放
    [self.moviePlayer play];
    
    //添加通知
    [self addNotification];
    
}

-(void)dealloc{
    //移除所有通知监控
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}


#pragma mark - 私有方法
/**
 *  取得本地文件路径
 *
 *  @return 文件路径
 */
-(NSURL *)getFileUrl{
    NSString *urlStr=[[NSBundle mainBundle] pathForResource:@"movie.mp4" ofType:nil];
    NSURL *url=[NSURL fileURLWithPath:urlStr];
    return url;
}

/**
 *  取得网络文件路径
 *
 *  @return 文件路径
 */
-(NSURL *)getNetworkUrl{
    NSString *urlStr= @"http://www.realank.com/movie.mp4";//@"http://mediaserver.enorth.com.cn:8083/videos/live/57/33/d3Hr2eCssqyV1/d3Hr2eCssqyV1.M3U8";
    urlStr=[urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSURL *url=[NSURL URLWithString:urlStr];
    return url;
}

/**
 *  创建媒体播放控制器
 *
 *  @return 媒体播放控制器
 */
-(MPMoviePlayerController *)moviePlayer{
    if (!_moviePlayer) {
        NSURL *url=[self getFileUrl];
        _moviePlayer=[[MPMoviePlayerController alloc]initWithContentURL:url];
        _moviePlayer.repeatMode = MPMovieRepeatModeOne;
        _moviePlayer.view.frame=CGRectMake(20, 100, 300, 300);
        _moviePlayer.view.autoresizingMask=UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
        _moviePlayer.controlStyle = MPMovieControlStyleEmbedded;
        [self.view addSubview:_moviePlayer.view];
    }
    return _moviePlayer;
}

/**
 *  添加通知监控媒体播放控制器状态
 */
-(void)addNotification{
    NSNotificationCenter *notificationCenter=[NSNotificationCenter defaultCenter];
    [notificationCenter addObserver:self selector:@selector(mediaPlayerPlaybackStateChange:) name:MPMoviePlayerPlaybackStateDidChangeNotification object:self.moviePlayer];
    [notificationCenter addObserver:self selector:@selector(mediaPlayerPlaybackFinished:) name:MPMoviePlayerPlaybackDidFinishNotification object:self.moviePlayer];
    [notificationCenter addObserver:self selector:@selector(movieLoadStateChanged:) name:MPMoviePlayerLoadStateDidChangeNotification object:self.moviePlayer];
    
}

/**
 *  播放状态改变，注意播放完成时的状态是暂停
 *
 *  @param notification 通知对象
 */
-(void)mediaPlayerPlaybackStateChange:(NSNotification *)notification{
    switch (self.moviePlayer.playbackState) {
        case MPMoviePlaybackStatePlaying:
            NSLog(@"正在播放...");
            break;
        case MPMoviePlaybackStatePaused:
            NSLog(@"暂停播放.");
            break;
        case MPMoviePlaybackStateStopped:
            NSLog(@"停止播放.");
            break;
        default:
            NSLog(@"播放状态:%li",self.moviePlayer.playbackState);
            break;
    }
}

/**
 *  播放完成
 *
 *  @param notification 通知对象
 */
-(void)mediaPlayerPlaybackFinished:(NSNotification *)notification{
    NSLog(@"播放完成.%li",self.moviePlayer.playbackState);
}

-(void)movieLoadStateChanged:(NSNotification *)notification{
    if (self.moviePlayer.loadState == MPMovieLoadStateUnknown) {
        self.moviePlayer.contentURL = [self getFileUrl];
        [self.moviePlayer play];
    }
}

@end

因为视频播放器全屏以后，会有快进快退的按钮，但是按了按钮以后，会造成黑屏，所以增加了name:MPMoviePlayerLoadStateDidChangeNotification通知，并且当
loadState为MPMovieLoadStateUnknown的时候，代码强制重新播放视频

当全屏了视频播放器以后，如果想支持横屏播放，需要再appDelegate里添加对应的方法：

//在didFinishLaunchingWithOptions中调用这个方法
- (void)addMoviePlaybackRotateNotification{
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(moviePlayerWillEnterFullscreenNotification:) name:MPMoviePlayerWillEnterFullscreenNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(moviePlayerWillExitFullscreenNotification:) name:MPMoviePlayerWillExitFullscreenNotification object:nil];

}

- (void) moviePlayerWillEnterFullscreenNotification:(NSNotification*)notification {
    self.allowRotation = YES;
}

- (void) moviePlayerWillExitFullscreenNotification:(NSNotification*)notification {
    self.allowRotation = NO;
}

-(UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window
{
    if (self.allowRotation) {
        
        return UIInterfaceOrientationMaskLandscapeRight | UIInterfaceOrientationMaskPortrait | UIInterfaceOrientationMaskLandscapeLeft;
    }
    return UIInterfaceOrientationMaskPortrait;
}

详情查看stack overflow中的内容