UIImagePickerController簡述：
UIImagePickerController 類是獲取選擇圖片和視頻的用戶接口，我們可以用UIImagePickerController選擇我們所需要的圖片和視頻。
注：UIImagePickerController不能夠任意定制，也不可以繼承生成子類。
一、UIImagePickerController的屬性：
1、sourceType
指定使用模式（照相機/相冊／照片庫）
enum {
UIImagePickerControllerSourceTypePhotoLibrary,
UIImagePickerControllerSourceTypeCamera,
UIImagePickerControllerSourceTypeSavedPhotosAlbum
};
2、BOOL showsCameraControls
設置拍照時的下方的工具欄是否顯示，如果需要自定義拍攝界面，則可把該工具欄隱藏。
3、BOOL allowsEditing
設置當拍照完或在相冊選完照片后，是否跳到編輯模式進行圖片剪裁
showsCameraControls=Yes時才有效果。
4、cameraDevice
判斷設備是否支持前置攝像頭／后置攝像頭
enum {
UIImagePickerControllerCameraDeviceRear,
UIImagePickerControllerCameraDeviceFront
};
5、cameraFlashMode
設置閃光燈模式
enum {
UIImagePickerControllerCameraFlashModeOff = -1,
UIImagePickerControllerCameraFlashModeAuto = 0,
UIImagePickerControllerCameraFlashModeOn = 1
};
6、mediaTypes
設置相機支持的類型，拍照和錄像
+ (NSArray *)availableMediaTypesForSourceType:(UIImagePickerControllerSourceType)sourceType
一共有三個可選的代理方法UIImagePickerControllerDelegate
– imagePickerController:didFinishPickingMediaWithInfo:
– imagePickerControllerDidCancel:
– imagePickerController:didFinishPickingImage:editingInfo:
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
info中包括選取的照片，視頻的主要信息
NSString *const UIImagePickerControllerMediaType; 選取的類型 public.image public.movie
NSString *const UIImagePickerControllerOriginalImage; 修改前的UIImage object.
NSString *const UIImagePickerControllerEditedImage; 修改后的UIImage object.
NSString *const UIImagePickerControllerCropRect; 原始圖片的尺寸NSValue object containing a CGRect data type
NSString *const UIImagePickerControllerMediaURL; 視頻在文件系統中 的 NSURL地址
7、cameraViewTransform
設置拍攝時屏幕的view的transform屬性，可以實現旋轉，縮放功能
enum{
CGAffineTransformMakeRotation；
CGAffineTransformMakeScale；
}
二、UIImagePickerController回調方法：
1、成功獲得相片或視頻后的回調
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info；
1 - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{ 2 //通過UIImagePickerControllerMediaType判斷返回的是照片還是視頻 3 NSString* type = [info objectForKey:UIImagePickerControllerMediaType]; 4 //如果返回的type等於kUTTypeImage，代表返回的是照片,並且需要判斷當前相機使用的sourcetype是拍照還是相冊 5 if ([type isEqualToString:(NSString*)kUTTypeImage]&&picker.sourceType==UIImagePickerControllerSourceTypeCamera) { 6 //獲取照片的原圖 7 UIImage* original = [info 8 objectForKey:UIImagePickerControllerOriginalImage]; 9 //獲取圖片裁剪的圖 10 UIImage* edit = [info objectForKey:UIImagePickerControllerEditedImage]; 11 //獲取圖片裁剪后，剩下的圖 12 UIImage* crop = [info objectForKey:UIImagePickerControllerCropRect]; 13 //獲取圖片的url 14 NSURL* url = [info objectForKey:UIImagePickerControllerMediaURL]; 15 //獲取圖片的metaData數據信息 16 NSDictionary* metaData = [info objectForKey:UIImagePickerControllerMediaMetadata]; 17 //如果是拍照的照片，則需要手動保存到本地，系統不會自動保存拍照成功后的照片 18 UIImageWriteToSavedPhotosAlbum(edit, self, @selector(image:didFinishSavingWithError:contextInfo:), nil); 19 }else{ 20 21 } 22 //模態方式退出uiimagepickercontroller 23 [imagepicker dismissModalViewControllerAnimated:YES]; 24 }
2、取消照相機的回調
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker；
1 - (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{ 2 //模態方式退出UIImagePickerController 3 [imagePicker dismissModalViewControllerAnimated:YES]; 4 }
3、保存照片成功后的回調
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo；
1 - (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error 2 contextInfo:(void *)contextInfo{ 3 4 }