typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) 
{
    UIImagePickerControllerSourceTypePhotoLibrary,
    UIImagePickerControllerSourceTypeCamera,
    UIImagePickerControllerSourceTypeSavedPhotosAlbum
} ```

`typedef NS_ENUM(NSInteger, UIImagePickerControllerQualityType) {
    UIImagePickerControllerQualityTypeHigh = 0,       
// highest quality
    UIImagePickerControllerQualityTypeMedium = 1,     
// medium quality, suitable for transmission via Wi-Fi 
    UIImagePickerControllerQualityTypeLow = 2,         
// lowest quality, suitable for tranmission via cellular network
    UIImagePickerControllerQualityType640x480,    
// VGA quality
    UIImagePickerControllerQualityTypeIFrame1280x720,
    UIImagePickerControllerQualityTypeIFrame960x540,
}`
 


`@interface UIImagePickerController : UINavigationController <NSCoding>`

`+ (BOOL)isSourceTypeAvailable:(UIImagePickerControllerSourceType)sourceType;  `
`+ (nullable NSArray<NSString *> *)availableMediaTypesForSourceType:(UIImagePickerControllerSourceType)sourceType;`
`+ (BOOL)isCameraDeviceAvailable:(UIImagePickerControllerCameraDevice)cameraDevice `
`+ (BOOL)isFlashAvailableForCameraDevice:(UIImagePickerControllerCameraDevice)cameraDevice `
`+ (nullable NSArray<NSNumber *> *)availableCaptureModesForCameraDevice:(UIImagePickerControllerCameraDevice)cameraDevice`

`@property(nullable,nonatomic,weak) id <UINavigationControllerDelegate, UIImagePickerControllerDelegate> delegate;`



`@protocol UIImagePickerControllerDelegate<NSObject>`
 
`- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info;`
`- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker;`
 








该类继承自UINavigationController类
调用摄像头或相册来获取图片和视频时都可以用此类解决

######iOS  获取图片有三种方法
***
1 直接调用摄像头拍照
2 从相册中选择
3 从图库中选择

UIImagePickerController 是系统提供的用来获取图片和视频的接口；
用UIImagePickerController 类来获取图片视频；
大体分为以下几个步骤：
初始化UIImagePickerController 类
设置UIImagePickerController 实例的数据来源类型（下面解释）�；
设置设置代理
如果需要做图片修改的话设置allowsEditing =yes

数据来源类型一共有三种：

<code>
enum {  
   UIImagePickerControllerSourceTypePhotoLibrary ,//来自图库  
   UIImagePickerControllerSourceTypeCamera ,//来自相机  
   UIImagePickerControllerSourceTypeSavedPhotosAlbum //来自相册  
};  
</code>

在用这些来源的时候最好检测以下设备是否支持；
<code>
if([UIImagePickerController isSourceTypeAvailable:
UIImagePickerControllerSourceTypeCamera])  
   {  
       NSLog(@"支持相机");  
   }  
   if([UIImagePickerController isSourceTypeAvailable:
UIImagePickerControllerSourceTypePhotoLibrary])  
   {  
       NSLog(@"支持图库");  
   }  
   if ([UIImagePickerController isSourceTypeAvailable:
UIImagePickerControllerSourceTypeSavedPhotosAlbum])  
   {  
       NSLog(@"支持相片库");  
   }  
</code>

调用摄像头来获取资源
<code>
-(void)viewDidLoad {  
    [super viewDidLoad];  
    picker = [[UIImagePickerController alloc]init];  
    picker.view.backgroundColor = [UIColor orangeColor];  
    UIImagePickerControllerSourceType sourcheType = UIImagePickerControllerSourceTypeCamera;  
    picker.sourceType = sourcheType;  
    picker.delegate = self;  
    picker.allowsEditing = YES;  
}  
</code>
上面只是实例了UIImagePickerController及其属性 在需要获取图片的时候需要弹出窗口调用
`[self presentViewController:picker animated:YES completion:nil];  `

我们还需要代理来获取我们选中的图片

######UIImagePickerControllerDelegate
***
有个3.0时 废弃略过
`- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info;`
当用户选取完成后调用；
`- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker;`
当用户取消选取时调用；
 
<code>
NSString \*const  UIImagePickerControllerMediaType ;指定用户选择的媒体类型（文章最后进行扩展）  
NSString \*const  UIImagePickerControllerOriginalImage ;原始图片  
NSString \*const  UIImagePickerControllerEditedImage ;修改后的图片  
NSString \*const  UIImagePickerControllerCropRect ;�裁剪尺寸  
NSString \*const  UIImagePickerControllerMediaURL ;媒体的URL  
NSString \*const  UIImagePickerControllerReferenceURL ;原件的URL  
NSString \*const  UIImagePickerControllerMediaMetadata;当来数据来源是照相机的时候这个值才有效  
</code>
http://kayosite.com/ios-development-and-detail-of-photo-framework.html/comment-page-1
转自：[iOS 获取图片](http://blog.csdn.net/u010123208/article/details/39493535)