UIImagePickerController

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

为了区分是否支持视频格式，一般要用到下面这个函数，以便确定mediaTypes。
+ (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
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
– imagePickerController:didFinishPickingMediaWithInfo:  
– imagePickerControllerDidCancel:  
– imagePickerController:didFinishPickingImage:editingInfo:   Deprecated in iPhone OS 3.0

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
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
实例代码如下：

- (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：

首先要遵守UIImagePickerControllerDelegate协议，然后实现协议的主要方法。

//拍照
- (IBAction)takePictureAction:(id)sender
{
    UIImagePickerController *imagePicker=[[UIImagePickerController alloc]init];
    if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
    {
        [imagePicker setSourceType:UIImagePickerControllerSourceTypeCamera];
    }
    else
    {
        [imagePicker setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];
    }
    [imagePicker setDelegate:self];
    [self presentViewController:imagePicker animated:YES completion:nil];
}

//选取图片之后
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    StudentStore *sharedStore=[StudentStore sharedStore];
    Student *p= [sharedStore currentStudent]; 
   
    ImageStore *iStore=[ImageStore sharedStore];
    NSString *oldKey=[p imagePath];
    if(oldKey)
    {
        //删除老照片
        [iStore deleteImageForKey:oldKey];
    }
   
    UIImage *image=[info objectForKey:UIImagePickerControllerOriginalImage];
   
    //生成唯一标志 CF:Core Foundation UUID:唯一标志 Ref:指针
    CFUUIDRef newUniqueID=CFUUIDCreate(kCFAllocatorDefault);
    //创建相应字符串
    CFStringRef newUniqueIDString =CFUUIDCreateString(kCFAllocatorDefault, newUniqueID);
    NSString *key=(__bridge NSString*)newUniqueIDString;
   
   
    [p setImagePath:key];
    [iStore setImage:image forKey:key];
    [self dismissViewControllerAnimated:YES completion:nil];
   
    CFRelease(newUniqueIDString);
    CFRelease(newUniqueID);
   
}