UIImagePickerController拍照与摄像

该类继承自UINavigationController类
步骤：
检查媒体来源模式是否可用
检查该来源模式下所支持的媒体类型
创建图像选取控制器，设置其属性并显示
在委托协议方法中处理

1.检查媒体来源
调用UIImagePickerController类的静态方法isSourceTypeAvailable来检查
sourceType是一个UIImagePickerControllerSourceType类型的枚举值，它表示图像选取控制器的3种不同的媒体来源模式
UIImagePickerControllerSourceTypePhotoLibrary:照片库模式。图像选取控制器以该模式显示时会浏览系统照片库的根目录。
UIImagePickerControllerSourceTypeCamera:相机模式，图像选取控制器以该模式显示时可以进行拍照或摄像。
UIImagePickerControllerSourceTypeSavedPhotosAlbum:相机胶卷模式，图像选取控制器以该模式显示时会浏览相机胶卷目录。
如果设备支持指定的媒体来源模式，则isSourceTypeAvailable:方法返回YES，否则返回NO。
2.检查支持的媒体类型
调用UIImagePickerController类的另一个静态方法availableMediaTypesForSourceType:
返回的是字符串数组，kUTTypeImage表示静态图片，kUTTypeMovie表示视频。这两个字符串常量定义在MobileCoreServices框架中。

参数info是一个字典，包含媒体类型，拍照的原始图片，编辑后的图片，或是摄像的视频文件的URL等。

//

// ViewController.h

// Camera

//

// Created by gao wuhang on 12-11-23.

// Copyright (c) 2012年 gaowuhang. All rights reserved.

//

#import

@interface
ViewController :UIViewController<</span>UINavigationControllerDelegate,UIImagePickerControllerDelegate>

- (IBAction)takePictureButtonClick:(id)sender;
- (IBAction)captureVideoButtonClick:(id)sender;

@end

//

// ViewController.m

// Camera

//

// Created by gao wuhang on 12-11-23.

// Copyright (c) 2012年 gaowuhang. All rights reserved.

//

#import "ViewController.h"

#import

#import

@interface ViewController()

@end

@implementationViewController

- (IBAction)takePictureButtonClick:(id)sender{

//检查相机模式是否可用


if(![UIImagePickerControllerisSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]){


NSLog(@"sorry, no camera or camera isunavailable.");
return;
}

//获得相机模式下支持的媒体类型


NSArray*availableMediaTypes = [UIImagePickerControlleravailableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];
BOOL canTakePicture =
NO;
for (NSString*
mediaTypein availableMediaTypes) {
if([mediaType
isEqualToString:(NSString*)kUTTypeImage]) {

//支持拍照

canTakePicture =YES;

break;

}
}

//检查是否支持拍照
if (!canTakePicture) {


NSLog(@"sorry, taking picture is notsupported.");
return;
}

//创建图像选取控制器

UIImagePickerController* imagePickerController =[[UIImagePickerControlleralloc]init];

//设置图像选取控制器的来源模式为相机模式

imagePickerController.sourceType=UIImagePickerControllerSourceTypeCamera;

//设置图像选取控制器的类型为静态图像
imagePickerController.mediaTypes = [[[NSArrayalloc]
initWithObjects:(NSString*)kUTTypeImage,nil]
autorelease];

//允许用户进行编辑
imagePickerController.allowsEditing =YES;

//设置委托对象
imagePickerController.delegate=self;

//以模视图控制器的形式显示

[selfpresentModalViewController:imagePickerController
animated:YES];
[imagePickerControllerrelease];
}

- (IBAction)captureVideoButtonClick:(id)sender{

//检查相机模式是否可用


if(![UIImagePickerControllerisSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]){


NSLog(@"sorry, no camera or camera isunavailable!!!");
return;
}

//获得相机模式下支持的媒体类型


NSArray*availableMediaTypes = [UIImagePickerControlleravailableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];
BOOL canTakeVideo =
NO;
for (NSString*
mediaTypein availableMediaTypes) {
if([mediaType
isEqualToString:(NSString *)kUTTypeImage]) {

//支持摄像

canTakeVideo =YES;

break;

}
}

//检查是否支持摄像
if (!canTakeVideo) {


NSLog(@"sorry, capturing video is notsupported.!!!");
return;
}

//创建图像选取控制器

UIImagePickerController* imagePickerController =[[UIImagePickerControlleralloc]init];

//设置图像选取控制器的来源模式为相机模式

imagePickerController.sourceType=UIImagePickerControllerSourceTypeCamera;

//设置图像选取控制器的类型为动态图像
imagePickerController.mediaTypes = [[[NSArrayalloc]
initWithObjects:(NSString*)kUTTypeMovie,nil]
autorelease];

//设置摄像图像品质

imagePickerController.videoQuality=UIImagePickerControllerQualityTypeHigh;

//设置最长摄像时间
imagePickerController.videoMaximumDuration =30;

//允许用户进行编辑
imagePickerController.allowsEditing =YES;

//设置委托对象
imagePickerController.delegate=self;

//以模式视图控制器的形式显示

[selfpresentModalViewController:imagePickerController
animated:YES];
[imagePickerControllerrelease];

}

- (void)image:(UIImage*)imagedidFinishSavingWithError:(NSError*)error
contextInfo:(void*)contextInfo{
if (!error) {


NSLog(@"picture saved with noerror.");
}
else
{


NSLog(@"error occured while saving thepicture%@", error);
}
}

- (void)imagePickerController:(UIImagePickerController *)pickerdidFinishPickingMediaWithInfo:(NSDictionary
*)info{

//打印出字典中的内容


NSLog(@"get the media info: %@", info);

//获取媒体类型

NSString*mediaType = [infoobjectForKey:UIImagePickerControllerMediaType];

//判断是静态图像还是视频
if ([mediaType
isEqualToString:(NSString *)kUTTypeImage]) {

//获取用户编辑之后的图像

UIImage*editedImage = [infoobjectForKey:UIImagePickerControllerEditedImage];

//将该图像保存到媒体库中


UIImageWriteToSavedPhotosAlbum(editedImage,self,@selector(image:didFinishSavingWithError:contextInfo:),NULL);
}elseif([mediaType
isEqualToString:(NSString *)kUTTypeMovie])



{



//获取视频文件的url



NSURL* mediaURL = [infoobjectForKey:UIImagePickerControllerMediaURL];



//创建ALAssetsLibrary对象并将视频保存到媒体库



ALAssetsLibrary* assetsLibrary= [[ALAssetsLibraryalloc]init];



[assetsLibrarywriteVideoAtPathToSavedPhotosAlbum:mediaURLcompletionBlock:^(NSURL
*assetURL,NSError *error) {



if (!error) {



NSLog(@"captured
video saved with noerror.");



}else



{



NSLog(@"erroroccured
while saving the video:%@", error);



}



}];



[assetsLibraryrelease];



}



[pickerdismissModalViewControllerAnimated:YES];

}

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

[picker dismissModalViewControllerAnimated:YES];
}




- (void)viewDidLoad
{

[superviewDidLoad];

// Do any additional setup after loading the view, typically from anib.
}

- (void)viewDidUnload
{

[superviewDidUnload];

// Release any retained subviews of themain view.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{


return(interfaceOrientation !=UIInterfaceOrientationPortraitUpsideDown);
}

@end