iOS：图像选取器控制器控件UIImagePickerController的详解

图像选择控制器:UIImagePickerController

功能：用于选取相册或相机等里面的照片。

@interface UIImagePickerController : UINavigationController

枚举：

//图片资源来源类型

typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {

UIImagePickerControllerSourceTypePhotoLibrary,          //图库

UIImagePickerControllerSourceTypeCamera,                 //相机

UIImagePickerControllerSourceTypeSavedPhotosAlbum   //相册

};

//摄像图像的质量

typedef NS_ENUM(NSInteger, UIImagePickerControllerQualityType) {

UIImagePickerControllerQualityTypeHigh = 0,          // 高质量

UIImagePickerControllerQualityTypeMedium = 1,      //中等质量,适合通过Wi-Fi传输

UIImagePickerControllerQualityTypeLow = 2,           // 最低的质量,适合通过蜂窝网络传输

UIImagePickerControllerQualityType640x480 = 3,             // VGA质量,640*480分辨率

UIImagePickerControllerQualityTypeIFrame1280x720 = 4,  // VGA质量1280*720分辨率

UIImagePickerControllerQualityTypeIFrame960x540 = 5    // VGA质量,960*540分辨率

};

//相机摄像模式

typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraCaptureMode) {

UIImagePickerControllerCameraCaptureModePhoto,  //图片

UIImagePickerControllerCameraCaptureModeVideo   //录像

};

//摄像头位置

typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraDevice) {

UIImagePickerControllerCameraDeviceRear,          //后摄像头

UIImagePickerControllerCameraDeviceFront          //前摄像头

};

//闪光灯状态模式

typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraFlashMode) {

UIImagePickerControllerCameraFlashModeOff  = -1,   //关闭状态

UIImagePickerControllerCameraFlashModeAuto = 0,   //自动调节状态

UIImagePickerControllerCameraFlashModeOn   = 1    //开启状态

};

图片信息中字典的键：

UIKIT_EXTERN NSString *const UIImagePickerControllerMediaType;       //用户自定义的媒体类型

UIKIT_EXTERN NSString *const UIImagePickerControllerOriginalImage;   // 原始的图片

UIKIT_EXTERN NSString *const UIImagePickerControllerEditedImage;     // 编辑后的图片

UIKIT_EXTERN NSString *const UIImagePickerControllerCropRect;        // 裁剪尺寸

UIKIT_EXTERN NSString *const UIImagePickerControllerMediaURL;        // 媒体URL

UIKIT_EXTERN NSString *const UIImagePickerControllerReferenceURL;  // 原件URL

UIKIT_EXTERN NSString *const UIImagePickerControllerMediaMetadata  // 仅有效于拍摄图片时

属性：

//图像选取代理

@property(nonatomic,assign)  id <UINavigationControllerDelegate, UIImagePickerControllerDelegate> delegate;

//图片资源来源类型,默认来自图库

@property(nonatomic)UIImagePickerControllerSourceType     sourceType;

//媒体类型数组

@property(nonatomic,copy)NSArray  *mediaTypes;

//是否允许编辑图像,默认为NO

@property(nonatomic) BOOL   allowsEditing ;

@property(nonatomic)  BOOL    allowsImageEditing ;

//录像最大时长,默认为10分钟

@property(nonatomic)  NSTimeInterval   videoMaximumDuration;

//录像质量

@property(nonatomic)  UIImagePickerControllerQualityType  videoQuality ；

//是否显示相机控制界面,默认显示

@property(nonatomic) BOOL  showsCameraControls ;

//设置视图覆盖预览视图

@property(nonatomic,retain)    UIView    *cameraOverlayView  ;

//相机视图仿射类型

@property(nonatomic) CGAffineTransform   cameraViewTransform ;

//相机摄像模式,默认为拍摄图片

@property(nonatomic) UIImagePickerControllerCameraCaptureMode cameraCaptureMode ;

//摄像头选取,默认为后摄像头

@property(nonatomic) UIImagePickerControllerCameraDevice cameraDevice ;

//闪光灯状态模式

@property(nonatomic) UIImagePickerControllerCameraFlashMode   cameraFlashMode;

方法：

//资源来源类型是否可用

+ (BOOL)isSourceTypeAvailable:(UIImagePickerControllerSourceType)sourceType;

//返回资源来源类型中可用的媒体类型数组

+ (NSArray *)availableMediaTypesForSourceType:(UIImagePickerControllerSourceType)sourceType;

//摄像头是否可用

+ (BOOL)isCameraDeviceAvailable:(UIImagePickerControllerCameraDevice)cameraDevice                   ;

//闪光灯是否可用

+ (BOOL)isFlashAvailableForCameraDevice:(UIImagePickerControllerCameraDevice)cameraDevice ;

//返回可用的相机模式数组

+ (NSArray *)availableCaptureModesForCameraDevice (UIImagePickerControllerCameraDevice)

cameraDevice;

//照相

- (void)takePicture;

//开始录频

- (BOOL)startVideoCapture ;

//停止录频

- (void)stopVideoCapture ;

代理：

@protocol UIImagePickerControllerDelegate<NSObject>

@optional

//选取编辑过的图片

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(NSDictionary *)editingInfo ;

//选取原始图片

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info;

//取消选取

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker;

@end

保存相关的函数：

// 保存图片到被保存的相册中

UIKIT_EXTERN void UIImageWriteToSavedPhotosAlbum(UIImage *image, id completionTarget, SEL completionSelector, void *contextInfo);

// - (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo;

// 保存指定路径的录频到被保存的相册中

UIKIT_EXTERN BOOL UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(NSString *videoPath) ;

// 保存录频到被保存的相册中

UIKIT_EXTERN void UISaveVideoAtPathToSavedPhotosAlbum(NSString *videoPath, id completionTarget, SEL completionSelector, void *contextInfo);

//- (void)video:(NSString *)videoPath didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo;

下面来举一个实例如下：从本地相册读取显示图片

1、设置故事板,往故事板的视图中拖入两个控件，一个是UIImageView,另一个是UIButton,分别命名为imageView、“相册”。

 

2、将imageView关联IBOutLet到控制器类中作为属性,给"相册"按钮关联IBAction事件，用来显示功能。还要让类实现图像选取器控制器协议和导航控制器协议

3、现在就是显示功能的实现和协议方法的实现了。

//按钮事件,打开相册(以模态窗口的形式显示相册)

- (IBAction)buttonClicked:(UIButton *)sender
{
    //创建图片选取控制器
    UIImagePickerController *imagePicker = [[UIImagePickerController alloc]init];

    //图片资源来自相册
    imagePicker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;

    //设置选取代理
    imagePicker.delegate = self;

    //使用模态窗口显示相册
    [self presentViewController:imagePicker animated:YES completion:nil];
}

- (void)viewDidLoad {
    [super viewDidLoad];

}

//实现协议方法,选取相册中的相片：

#pragma mark -<UIImagePickercontrollerDelegate>

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    //NSLog(@"%@",info);
    /*info：这个字典中放着图片的具体信息,通过这个字典的键可以获取图片*/
    //取出图片
    self.image = [info objectForKey:UIImagePickerControllerOriginalImage];//显示图片在图像视图中
    [self.imageView setImage:self.image];

    //关闭模态窗口
    [picker dismissViewControllerAnimated:YES completion:nil];
}

4、演示结果：

开始运行截图：                                                    显示的本地相册截图：

   

选取某一图片截图：                                              点击"相册"返回,再选取某一图片截图：