UIImagePickerController学习

UIImagePickerController概述：
UIImagePickerController 类是获取选择图片和视频的用户接口。我们可以用这个controller选择我们所需要的图片和视频。对于这个类来说比较特殊，我们不能够任意定制，也不可以继承生成子类。
我们在用UIImagePickerController类的时候，只需要调用用代码实现其在什么位置显示和开始，当然我们之后可以选择所需的图片和影片，或者也可以不选择点击取消即可。
但是在我们调用接口之前，我们需要确认：
一：当前设备是否支持使用UIImagePickerController，这个时候我们需要调用isSourceTypeAvailable:方法判断。
二：查看符合的媒体类型（图片或者视频），这个时候我们调用availableMediaTypesForSourceType: 方法判断。
同时使用UIImagePickerController时，我们需要UIImagePickerControllerDelegate协议代理实现一些特定时间特定的动作。在调用摄像头的时候我们可以选择使用闪光灯，但是默认条件下对视频有10分钟的限制，需要用videoMaximumDuration属性更改默认时间，
三：之后我们设定界面媒体的属性  
1：sourceType  //从哪选取媒体
enum {
UIImagePickerControllerSourceTypePhotoLibrary,
UIImagePickerControllerSourceTypeCamera,
UIImagePickerControllerSourceTypeSavedPhotosAlbum
};
typedef NSUInteger UIImagePickerControllerSourceType;
2:   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
一共有三个可选的代理方法UIImagePickerControllerDelegate 
– imagePickerController:didFinishPickingMediaWithInfo:  
– imagePickerControllerDidCancel:  
– imagePickerController:didFinishPickingImage:editingInfo: 
-(void)pick{
[imagePickertakePicture];
}
-(IBAction)press:(id)sender {
imagePicker= ［UIImagePickerController alloc] init];
= self;
= [UIImagePickerControlleravailableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];
= UIImagePickerControllerSourceTypeCamera;
= NO;

UIView*view = ［UIView alloc] initWithFrame:CGRectMake(0, 0, 320,44)];
= [UIColor redColor];
UIButton*button = ［UIButton alloc] initWithFrame:CGRectMake(0, 0, 40,40)];
= [UIColor blueColor];
[buttonaddTarget:self action:@selector(pick)forControlEvents:UIControlEventTouchUpInside];
[viewaddSubview:button];

CGRectnewFrame = CGRectMake(0.0,436,320,44);
= newFrame;
= view;
[selfpresentModalViewController:imagePickeranimated:YES];
}
-(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
if(［info objectForKey:UIImagePickerControllerMediaType]isEqualToString:(NSString*)kUTTypeImage]) {
UIImage*image = [infoobjectForKey:UIImagePickerControllerOriginalImage];
UIImageWriteToSavedPhotosAlbum(image,self, @selector(image:didFinishSavingWithError:contextInfo:),nil);
} elseif (［info objectForKey:UIImagePickerControllerMediaType]isEqualToString:(NSString*)kUTTypeMovie]) {
NSString*path = ［info objectForKey:UIImagePickerControllerMediaURL]path];
   UISaveVideoAtPathToSavedPhotosAlbum(path,self, @selector(video:didFinishSavingWithError:contextInfo:),nil);
}
[pickerdismissModalViewControllerAnimated:YES];
}
-(void)imagePickerControllerDidCancel:(UIImagePickerController*)picker {
[pickerdismissModalViewControllerAnimated:YES];
}