UIImagePickerController

中期视讯 HD》ipad终于上线了，闲着无事，研究下UIImagePickerController的使用方法。

引用UIImagePickerController  需用到两个代理<UIImagePickerControllerDelegate,UINavigationControllerDelegate>

用UIImagePickerController选择、显示图片或视频，主要注意UIImagePickerController几个属性的设置
一：UI 显示样式，显示的格式确定
1：sourceType
@property(nonatomic) UIImagePickerControllerSourceType sourceType
enum {
UIImagePickerControllerSourceTypePhotoLibrary,
UIImagePickerControllerSourceTypeCamera,
UIImagePickerControllerSourceTypeSavedPhotosAlbum
};
typedef NSUInteger UIImagePickerControllerSourceType;
sourceType用来确定用户界面显示的样式：
共三种格式（模拟器上的效果图）
UIImagePickerControllerSourceTypePhotoLibrary,

UIImagePickerControllerSourceTypeCamera,

UIImagePickerControllerSourceTypeSavedPhotosAlbum

为了区分是否支持所需引用的sourceType，一般要用到下面这个函数，以便确定sourceType。

+ (BOOL)isSourceTypeAvailable:(UIImagePickerControllerSourceType)sourceType

2:   mediaTypes
@property(nonatomic,copy) NSArray *mediaTypes
mediaTypes用来确定再picker里显示那些类型的多媒体文件，图片？视频？
+ (NSArray *)availableMediaTypesForSourceType:(UIImagePickerControllerSourceType)sourceType

 

UIImagePikerController的一些属性和方法：

 

@property(nonatomic)           UIImagePickerControllerSourceType     sourceType;                  

@property(nonatomic,copy)      NSArray                              *mediaTypes;                   //是否允许对获得的图片进行编辑,default value is NO.

@property(nonatomic)           BOOL                                  allowsEditing 

@property(nonatomic)           BOOL                                  allowsImageEditing 

//视频最大的时间长度

@property(nonatomic)           NSTimeInterval                        videoMaximumDuration

//拍摄照片的清晰度，只有在照相机模式下可用

 

enum {

    UIImagePickerControllerQualityTypeHigh = 0,       // highest quality 

    UIImagePickerControllerQualityType640x480 = 3,    // VGA quality

    UIImagePickerControllerQualityTypeMedium = 1,     // medium quality, suitable for transmission via Wi-Fi 

    UIImagePickerControllerQualityTypeLow = 2         // lowest quality, suitable for tranmission via cellular network

};

typedef NSUInteger UIImagePickerControllerQualityType;

默认UIImagePickerControllerQualityTypeMedium

 

@property(nonatomic)           UIImagePickerControllerQualityType    videoQuality

//是否显示照相机其他控件，默认yes

@property(nonatomic)           BOOL                                  showsCameraControls

//类似相框

@property(nonatomic,retain)    UIView                                *cameraOverlayView 

@property(nonatomic)           CGAffineTransform                     cameraViewTransform

//可以设置照相机的模式，照相还是录视频，默认照相模式。

 

enum {

    UIImagePickerControllerCameraCaptureModePhoto,

    UIImagePickerControllerCameraCaptureModeVideo

};

typedef NSUInteger UIImagePickerControllerCameraCaptureMode;

 

@property(nonatomic) UIImagePickerControllerCameraCaptureMode cameraCaptureMode

//设置哪个引用摄像头，前置还是后置摄像头

@property(nonatomic) UIImagePickerControllerCameraDevice      cameraDevice  

//设置闪光灯模式

enum {

    UIImagePickerControllerCameraFlashModeOff  = -1,

    UIImagePickerControllerCameraFlashModeAuto = 0,

    UIImagePickerControllerCameraFlashModeOn   = 1

};

typedef NSInteger UIImagePickerControllerCameraFlashMode;   

@property(nonatomic) UIImagePickerControllerCameraFlashMode   cameraFlashMode  

 

 

 

二：选取动作处理
UIImagePickerControllerDelegate 
通过代理来完成用户在选中图片，或者choose视频时的处理方式：
共有三个可选的代理方法

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

 

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

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

 

 

info中包括选取的照片，视频的主要信息
NSString *const UIImagePickerControllerMediaType;         选取的类型 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;           原始图片的尺寸NSValue object containing a CGRect data type
NSString *const UIImagePickerControllerMediaURL;          视频在文件系统中 的 NSURL地址
保存视频主要时通过获取其NSURL 然后转换成NSData

 

保存图片、视频的方法。

 

// Adds a photo to the saved photos album.  The optional completionSelector should have the form:

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

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

 

// Is a specific video eligible to be saved to the saved photos album? 

UIKIT_EXTERN BOOL UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(NSString *videoPath) __OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_3_1);

 

// Adds a video to the saved photos album. The optional completionSelector should have the form:

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

UIKIT_EXTERN void UISaveVideoAtPathToSavedPhotosAlbum(NSString *videoPath, id completionTarget, SEL completionSelector, void *contextInfo) __OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_3_1);

 

 

 

实例代码如下：

实例一：
- (void) pickImage: (id) sender
{
UIImagePickerController *ipc = [[UIImagePickerController alloc] init];
        if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]){
     ipc.sourceType =  UIImagePickerControllerSourceTypePhotoLibrary;
      ipc.mediaTypes =[UIImagePickerController availableMediaTypesForSourceType:ipc.sourceType];   
        } 
ipc.delegate = self;
ipc.allowsImageEditing = NO;
[self presentModalViewController:ipc animated:YES]; 
}
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
if ([mediaType isEqualToString:@"public.image"]){
// UIImage *selectedImage = [info objectForKey:UIImagePickerControllerOriginalImage];
UIImage *image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
    NSLog(@"found an image");
[UIImageJPEGRepresentation(image, 1.0f) writeToFile:[self findUniqueSavePath] atomically:YES];
    SETIMAGE(image);
CFShow([[NSFileManager defaultManager] directoryContentsAtPath:[NSHomeDirectory() stringByAppendingString:@"/Documents"]]);
}
else if ([mediaType isEqualToString:@"public.movie"]){
NSURL *videoURL = [info objectForKey:UIImagePickerControllerMediaURL];
NSLog(@"found a video");
        NSData *webData = [NSData dataWithContentsOfURL:videoURL];
//NSData *video = [[NSString alloc] initWithContentsOfURL:videoURL];
[webData writeToFile:[self findUniqueMoviePath] atomically:YES];
CFShow([[NSFileManager defaultManager] directoryContentsAtPath:[NSHomeDirectory() stringByAppendingString:@"/Documents"]]);
// NSLog(videoURL);
}
[picker dismissModalViewControllerAnimated:YES];
}

 

实例二：主要介绍怎么修改获取图片的方法

加一个图片处理方法的类：

 

 

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)selectedImage editingInfo:(NSDictionary *)editingInfo {

 

CGFloat scale = 100/selectedImage.size.height;

 

UIImage *newpetimage = [selectedImage scaleToSize:CGSizeMake(selectedImage.size.width*scale, selectedImage.size.height*scale)];

NSLog(@"imagew = %f,h = %f",newpetimage.size.width,newpetimage.size.height);

 

}