UIImagePickerController(照相机)

UIImagePickerController:
1. 有三种工作模式：

//打开图片库根目录选择
UIImagePickerControllerSourceTypePhotoLibrary
//使用相机选择
UIImagePickerControllerSourceTypeCamera
//打开SavedPhoto目录选择
UIImagePickerControllerSourceTypeSavedPhotosAlbum

2. //用此方法可以判断，设备是否有拍照功能。
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
       
        //用模式窗体转换到图片选取界面。
        UIImagePickerController *aImagePickerController = [[UIImagePickerController alloc] init];
        aImagePickerController.delegate = self;
        aImagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
        BarStreetAppDelegate *delegate = [[UIApplication sharedApplication] delegate];
        [delegate.navController presentModalViewController:aImagePickerController animated:YES];
        [aImagePickerController release];
}

3. //两个主要的委托方法
#pragma mark UIImagePickerController Delegate Methods
//返回选取的图片
- (void)imagePickerController:(UIImagePickerController *)picker
        didFinishPickingImage:(UIImage *)image
                  editingInfo:(NSDictionary *)editingInfo {
    aImageView.image=image;
    [picker dismissModalViewControllerAnimated:YES];  
}
//选取结束时调用
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
    [picker dismissModalViewControllerAnimated:YES]; 
}

4. iPhone Simulator获取获取图片方法。
  a. 使用safari，按住图片，选择保存；
  b.（来自http://stackoverflow.com/questions/468879/adding-images-to-iphone-simulator）Go to ~/Library/Application Support/iPhone Simulator/User/Media/DCIM/100APPLE/ and add IMG_nnnn.THM and IMG_nnnn.JPG. It doesn't matter if they are not JPEGs - they can both be PNGs, but it appears that both of them must be present for it to work. You may need to create DCIM if it doesn't already exist, and in that case you should start nnnn from 0001. The JPG files are the fullsize version, while the THM files are the thumbnail, and are 75x75 pixels in size. I wrote a script to do this, but there's a better documented one over here.

You can also add photos from safari in the simulator, by Tapping and Holding on the image. If you drag an image (or any other file, like a PDF) to the simulator, it will immediately open Safari and display the image, so this is quite an easy way of getting images to it.

文章来源：http://lishuaishuai.iteye.com/category/145130?show_full=true

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);

 

}