9、AVFoundation

调用系统封装好的播放界面

//视频播放的url
    NSURL *playerURL = [NSURL fileURLWithPath:self.datasource[indexPath.row]];
    //初始化
    self.playerView = [[AVPlayerViewController alloc]init];
    //AVPlayerItem 视频的一些信息  创建AVPlayer使用的
    AVPlayerItem *item = [[AVPlayerItem alloc]initWithURL:playerURL];
    //通过AVPlayerItem创建AVPlayer
    self.player = [[AVPlayer alloc]initWithPlayerItem:item];
    //设置AVPlayerViewController内部的AVPlayer为刚创建的AVPlayer
    self.playerView.player = self.player;
    //关闭AVPlayerViewController内部的约束
    self.playerView.view.translatesAutoresizingMaskIntoConstraints = YES;
    [self presentViewController:self.playerView animated:YES completion:nil];

播放一段文本

将文本当做声音播放（默认播放英文）
AVSpeechSynthesizer *syn = [[AVSpeechSynthesizeralloc]init];
AVSpeechUtterance *utterance = [[AVSpeechUtterancealloc]initWithString:@“hello world"];
[syn speakUtterance:utterance];

AVAduioSession 应用程序与音频会话交互的接口

session = [AVAudioSession sharedInstance]//获取session单利
[session setCateGory:AVAudioSessionCategoryPlayback error:&error];//     设置会话模式
[session setActive:YES error:&error];//激活设置的模式
AVAudioPlayer 音频播放器属性
self.audioPlayer.numberOfLoops = -1;//循环
self.audioPlayer.volume = self.volumeValue;//音量
self.audioPlayer.pan = self.panValue;//左右声道
self.audioPlayer.enableRate = YES;
self.audioPlayer.rate = 1;//播放速率
音频会话的中断通知
//添加中断通知
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleInterruption:) name:AVAudioSessionInterruptionNotification object:[AVAudioSession sharedInstance]];

权限判断

• 相机权限判断

#import <AVFoundation/AVCaptureDevice.h>
#import <AVFoundation/AVMediaFormat.h>
AVAuthorizationStatus authStatus = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
if (authStatus == AVAuthorizationStatusRestricted || authStatus ==AVAuthorizationStatusDenied)
{
    //无权限
}

• 相册权限判断

#import <AssetsLibrary/AssetsLibrary.h>
ALAuthorizationStatus author = [ALAssetsLibraryauthorization Status];
    if (author == kCLAuthorizationStatusRestricted || author ==kCLAuthorizationStatusDenied){
        //无权限
    }
    typedef enum {
        kCLAuthorizationStatusNotDetermined = 0, // 用户尚未做出选择这个应用程序的问候
        kCLAuthorizationStatusRestricted,        // 此应用程序没有被授权访问的照片数据。可能是家长控制权限
        kCLAuthorizationStatusDenied,            // 用户已经明确否认了这一照片数据的应用程序访问
        kCLAuthorizationStatusAuthorized         // 用户已经授权应用访问照片数据} CLAuthorizationStatus;
    }

• 打开应用程序权限设置
  [[UIApplication sharedApplication]openURL:[NSURLURLWithString:UIApplicationOpenSettingsURLString]];

开关手电筒

AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    if ([device hasTorch]) {
        [device lockForConfiguration:nil];
        if (open) {
            [device setTorchMode:AVCaptureTorchModeOn];
        } else {
            [device setTorchMode:AVCaptureTorchModeOff];
        }
        [device unlockForConfiguration];
    }