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。
- (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 = [info objectForKey:UIImagePickerControllerMediaURL];
//创建ALAssetsLibrary对象并将视频保存到媒体库
ALAssetsLibrary* assetsLibrary = [[ALAssetsLibrary alloc] init];
[assetsLibrary writeVideoAtPathToSavedPhotosAlbum:mediaURL completionBlock:^(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];
}
