iOS开发之UIImagePickerController详解

1.UIImagePickerController的静态方法:  

imagepicker = [[UIImagePickerController alloc]init];  //UIImagePickerController静态方法判断设备是否支持照相机／图片库／相册功能  /*  typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {  UIImagePickerControllerSourceTypePhotoLibrary,  UIImagePickerControllerSourceTypeCamera,  UIImagePickerControllerSourceTypeSavedPhotosAlbum  };  */  BOOL isCameraSupport = [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];  NSLog(@"support camera:%d",isCameraSupport);    //UIImagePickerController静态方法判断设备是否支持前置摄像头／后置摄像头  /*  typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraDevice) {  UIImagePickerControllerCameraDeviceRear,  UIImagePickerControllerCameraDeviceFront  };  */  BOOL isRearSupport = [UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear];  NSLog(@"rear support:%d",isRearSupport);    //UIImagePickerController静态方法判断设备是否支持前置摄像头闪光灯／后置摄像头闪光灯  /*  typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraDevice) {  UIImagePickerControllerCameraDeviceRear,  UIImagePickerControllerCameraDeviceFront  };  */  BOOL isFlushSupport = [UIImagePickerController isFlashAvailableForCameraDevice:UIImagePickerControllerCameraDeviceRear];  NSLog(@"rear flash support:%d",isFlushSupport);    //UIImagePickerController静态方法返回前置摄像头／后置摄像头支持的拍摄类型  /*  typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraDevice) {  UIImagePickerControllerCameraDeviceRear,  UIImagePickerControllerCameraDeviceFront  };  */  //返回类型有照片和视频  /*  enum {  UIImagePickerControllerCameraCaptureModePhoto,  UIImagePickerControllerCameraCaptureModeVideo  };  typedef NSUInteger UIImagePickerControllerCameraCaptureMode;  */  NSArray* captureModes = [UIImagePickerController availableCaptureModesForCameraDevice:UIImagePickerControllerCameraDeviceRear];  for (NSNumber* mode in captureModes) {      NSLog(@"capture modes:%d",[mode integerValue]);  }    //UIImagePickerController静态方法返回照相机／相册／照片库所支持的媒体类型  /*  typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {  UIImagePickerControllerSourceTypePhotoLibrary,  UIImagePickerControllerSourceTypeCamera,  UIImagePickerControllerSourceTypeSavedPhotosAlbum  };  */  //返回类型有kUTTypeMovie,kUTTypeImage，其他类型均在<MobileCoreServices/MobileCoreServices.h>下  NSArray* mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];  for (NSString* type in mediaTypes) {      NSLog(@"media types:%@",type);  }

2.UIImagePickerController属性详解：

//指定使用照相机模式,可以指定使用相册／照片库  imagepicker.sourceType = UIImagePickerControllerSourceTypeCamera;  //设置当拍照完或在相册选完照片后，是否跳到编辑模式进行图片剪裁。只有当showsCameraControls属性为true时才有效果  imagepicker.allowsEditing = YES;  //设置拍照时的下方的工具栏是否显示，如果需要自定义拍摄界面，则可把该工具栏隐藏  imagepicker.showsCameraControls  = YES;  //设置使用后置摄像头，可以使用前置摄像头  imagepicker.cameraDevice = UIImagePickerControllerCameraDeviceRear;  //设置闪光灯模式  /*  typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraFlashMode) {  UIImagePickerControllerCameraFlashModeOff  = -1,  UIImagePickerControllerCameraFlashModeAuto = 0,  UIImagePickerControllerCameraFlashModeOn   = 1  };  */  imagepicker.cameraFlashMode = UIImagePickerControllerCameraFlashModeAuto;  //设置相机支持的类型，拍照和录像  imagepicker.mediaTypes = @[(NSString*)kUTTypeImage,(NSString*)kUTTypeMovie];  //设置拍摄时屏幕的view的transform属性，可以实现旋转，缩放功能  // imagepicker.cameraViewTransform = CGAffineTransformMakeRotation(M_PI*45/180);  // imagepicker.cameraViewTransform = CGAffineTransformMakeScale(1.5, 1.5);  //所有含有cameraXXX的属性都必须要sourceType是UIImagePickerControllerSourceTypeCamera时设置才有效果，否则会有异常  //设置UIImagePickerController的代理  imagepicker.delegate = self;    -(void)showCamera{      //用模态方式呈现imagepicker      [self presentModalViewController:imagepicker animated:YES];  }    //使用 imagepicker.cameraViewTransform = CGAffineTransformMakeRotation(M_PI*45/180);旋转45度的效果：      //使用 imagepicker.cameraViewTransform = CGAffineTransformMakeScale(1.5, 1.5);全屏的效果，同时imagepicker.showsCameraControls  = NO;隐藏工具栏：      //使用 imagepicker.allowsEditing = YES;出现的图片编辑效果，只有当imagepicker.showsCameraControls = YES;才有效果：      //使用 imagepicker.mediaTypes = @[(NSString*)kUTTypeImage,(NSString*)kUTTypeMovie];支持拍照和视频的前后对比效果

3.UIImagePickerController回调详解：

//成功获得相片还是视频后的回调  - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{      //通过UIImagePickerControllerMediaType判断返回的是照片还是视频      NSString* type = [info objectForKey:UIImagePickerControllerMediaType];      //如果返回的type等于kUTTypeImage，代表返回的是照片,并且需要判断当前相机使用的sourcetype是拍照还是相册      if ([type isEqualToString:(NSString*)kUTTypeImage]&&picker.sourceType==UIImagePickerControllerSourceTypeCamera) {          //获取照片的原图          UIImage* original = [info objectForKey:UIImagePickerControllerOriginalImage];          //获取图片裁剪的图          UIImage* edit = [info objectForKey:UIImagePickerControllerEditedImage];          //获取图片裁剪后，剩下的图          UIImage* crop = [info objectForKey:UIImagePickerControllerCropRect];          //获取图片的url          NSURL* url = [info objectForKey:UIImagePickerControllerMediaURL];          //获取图片的metadata数据信息          NSDictionary* metadata = [info objectForKey:UIImagePickerControllerMediaMetadata];          //如果是拍照的照片，则需要手动保存到本地，系统不会自动保存拍照成功后的照片          UIImageWriteToSavedPhotosAlbum(edit, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);      }else{                }      //模态方式退出uiimagepickercontroller      [imagepicker dismissModalViewControllerAnimated:YES];  }  //取消照相机的回调  - (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{      //模态方式退出uiimagepickercontroller      [imagepicker dismissModalViewControllerAnimated:YES];  }  //保存照片成功后的回调  - (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error  contextInfo:(voidvoid *)contextInfo{            NSLog(@"saved..");  }

4.自定义相机拍照画面：

//设置拍照时的下方的工具栏是否显示，如果需要自定义拍摄界面，则可把该工具栏隐藏  imagepicker.showsCameraControls  = NO;    UIToolbar* tool = [[UIToolbar alloc]initWithFrame:CGRectMake(0, self.view.frame.size.height-55, self.view.frame.size.width, 75)];  tool.barStyle = UIBarStyleBlackTranslucent;  UIBarButtonItem* cancel = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(cancelCamera)];  UIBarButtonItem* add = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemSave target:self action:@selector(savePhoto)];  [tool setItems:[NSArray arrayWithObjects:cancel,add, nil nil]];  //把自定义的view设置到imagepickercontroller的overlay属性中    imagepicker.cameraOverlayView = tool;    -(void)cancelCamera{      [imagepicker dismissModalViewControllerAnimated:YES];  }  -(void)savePhoto{      //拍照，会自动回调- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info，对于自定义照相机界面，拍照后回调可以不退出实现连续拍照效果      [imagepicker takePicture];  }

5.UIImagePickerController是继承UINavigationController,所以可以push和pop一些viewcontroller进行导航效果。例如，自定义照相机画面的时候可以在拍摄完后push一个viewcontroller用于对照片进行编辑。