從攝像頭獲取照片和視頻

• UIImagePickerController

• 可通過UIImagePickerController獲取視頻

  • 錄制長達30min的視頻
  • 將視頻文件路徑以NSString形式傳遞給應(yīng)用程序

• 可設(shè)置使用前置或后置攝像頭菠净，是否使用LED燈祟剔，是否允許用戶裁剪或調(diào)整照片或視頻

• 工作方式：

  • 創(chuàng)建實例
  • 根據(jù)需要配置選取器
  • 選取器包含一個符合UIImagePickerControllerDelegate協(xié)議的委托對象
  • 當前的視圖控制器通常會調(diào)用presentViewController:animated:completion:，所以視圖控制器呈現(xiàn)為模態(tài)
  • 用戶完成照片或視頻后乡小，委托對象接收imagePickerController:didFinishPickingMediaWithInfo:消息
    • 后者接收一個字典，包含用戶獲取的媒體信息
      • 原始或編輯過的照片
      • 視頻文件位置
      • 或其他有用信息
    • 需調(diào)用dismissViewControllerAnimated:completion:釋放圖片選取器
  • 用戶選擇取消圖片選擇器鹉梨，委托對象接收imagePickerControllerDidCancel:
    • 需調(diào)用dismissViewControllerAnimated:completion:釋放圖片選取器常柄，否則，取消按鈕不會起任何作用

• 判斷有哪些攝像頭可用+ isSourceTypeAvailable:

  if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
  {
      //攝像頭存在至少一個攝像頭
  }else
  {
      //攝像頭不可用
  }
  

• 判斷前置或后置攝像頭是否可用+ isCameraDeviceAvailable:

  if([UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllercameraDeviceFront])
  {
      //前置攝像頭可用
  }
  if([UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear])
  {
      //后置攝像頭可用
  }
  

• 拍照實例部分代碼

  - (IBAction)takePhoto:(id)sender
  {
          UIImagePickerController *pickerController = [[UIImagePickerController alloc]init];
  
          if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
          {
              //設(shè)置視圖控制器控制攝像頭
           pickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
      
              if ([UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceFront]) {
                  pickerController.cameraDevice = UIImagePickerControllerCameraDeviceFront;
          }else{
                  pickerController.cameraDevice = UIImagePickerControllerCameraDeviceRear;
          }
      
          pickerController.delegate = self;
          
          //將當前的視圖控制器拿掉
          [self presentViewController:pickerController animated:YES completion:nil];
      }
  }
  
  //視圖控制器的UIImagePickerControllerDelegate方法
  - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
  {
          UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
       self.imageView.image = image;
  
          [picker dismissViewControllerAnimated:YES completion:nil];
  }
  
  - (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
  {
          [picker dismissViewControllerAnimated:YES completion:nil];
  }