//引入系統文件
#import <AVFoundation/AVFoundation.h>
#import <AVKit/AVKit.h>
@interface ViewController ()
/**
 * 控制視頻播放的控件
 */
@property (weak, nonatomic) IBOutlet UISlider *progressSlider;
/**
 * 聲明播放視頻的控件屬性[既可以播放視頻也可以播放音頻]
 */
@property (nonatomic,strong)AVPlayer *player;
/**
 * 播放的總時長
 */
@property (nonatomic,assign)CGFloat sumPlayOperation;
 
 
@end
 
@implementation ViewController
 
- (void)viewDidLoad {
 [super viewDidLoad];
 // Do any additional setup after loading the view, typically from a nib.
 //設置播放的url
 NSString *playString = @"http://static.tripbe.com/videofiles/20121214/9533522808.f4v.mp4";
 NSURL *url = [NSURL URLWithString:playString];
 //設置播放的項目
 AVPlayerItem *item = [[AVPlayerItem alloc] initWithURL:url];
 //初始化player對象
 self.player = [[AVPlayer alloc] initWithPlayerItem:item];
 //設置播放頁面
 AVPlayerLayer *layer = [AVPlayerLayer playerLayerWithPlayer:_player];
 //設置播放頁面的大小
 layer.frame = CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, 300);
 layer.backgroundColor = [UIColor cyanColor].CGColor;
 //設置播放窗口和當前視圖之間的比例顯示內容
 layer.videoGravity = AVLayerVideoGravityResizeAspect;
 //添加播放視圖到self.view
 [self.view.layer addSublayer:layer];
 //設置播放進度的默認值
 self.progressSlider.value = 0;
 //設置播放的默認音量值
 self.player.volume = 1.0f;
  
}
#pragma mark - 開始按鈕響應方法
- (IBAction)startPlayer:(id)sender {
 [self.player play];
}
#pragma mark - 暫停按鈕響應方法
- (IBAction)stopPlayer:(id)sender {
 [self.player pause];
}
#pragma mark - 改變進度
- (IBAction)changeProgress:(id)sender {
 self.sumPlayOperation = self.player.currentItem.duration.value/self.player.currentItem.duration.timescale;
 //CMTimeMake(a,b) a表示當前時間，b表示每秒鐘有多少幀
 [self.player seekToTime:CMTimeMakeWithSeconds(self.progressSlider.value*self.sumPlayOperation, self.player.currentItem.duration.timescale) completionHandler:^(BOOL finished) {
  [self.player play];
 }];
  
}