UIImagePickerController 的简单实用

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。

#import

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

- (IBAction)takePictureButtonClick:(id)sender;

- (IBAction)captureVideoButtonClick:(id)sender;

@end

#import "ViewController.h"

#import

#import

@interface ViewController ()

@end

@implementation ViewController

- (IBAction)takePictureButtonClick:(id)sender{

//检查相机模式是否可用

if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
{

NSLog(@"sorry,
no camera or camera is unavailable.");

return;

}

//获得相机模式下支持的媒体类型

NSArray*
availableMediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];

BOOL canTakePicture = NO;

for (NSString* mediaType in 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 not supported.");

return;

}

//创建图像选取控制器

UIImagePickerController* imagePickerController = [[UIImagePickerController alloc] 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 = [[[NSArray alloc] 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

[self presentModalViewController:imagePickerController animated:YES];

[imagePickerController release];

}

- (IBAction)captureVideoButtonClick:(id)sender{

//检查相机模式是否可用

if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
{

NSLog(@"sorry,
no camera or camera is unavailable!!!");

return;

}

//获得相机模式下支持的媒体类型

NSArray*
availableMediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];

BOOL canTakeVideo = NO;

for (NSString* mediaType in 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 not supported.!!!");

return;

}

//创建图像选取控制器

UIImagePickerController* imagePickerController = [[UIImagePickerController alloc] 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 = [[[NSArray alloc] 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

[self presentModalViewController:imagePickerController animated:YES];

[imagePickerController release];

}

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

if (!error) {

NSLog(@"picture
saved with no error.");

}

else

{

NSLog(@"error
occured while saving the picture%@", error);

}

}

- (void)imagePickerController:(UIImagePickerController *)picker
didFinishPickingMediaWithInfo:(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 = [info objectForKey: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 = [info objectForKey:UIImagePickerControllerEditedImage];

//将该图像保存到媒体库中

UIImageWriteToSavedPhotosAlbum(editedImage, self,@selector(image:didFinishSavingWithError:contextInfo:), NULL);

}else if ([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 =
[[ALAssetsLibrary alloc]init];

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

if (!error) {

NSLog(@"captured
video saved with no error.");

}else

{

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

}

}];

[assetsLibrary release];

}

[picker dismissModalViewControllerAnimated:YES];

}

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

[picker dismissModalViewControllerAnimated:YES];

}

- (void)viewDidLoad

{

[super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

}

- (void)viewDidUnload

{

[super viewDidUnload];

// Release any retained subviews of the main view.

}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation

{

return (interfaceOrientation
!= UIInterfaceOrientationPortraitUpsideDown);

}

@end