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。
- (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)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];
}
//load user image
- (void)UesrImageClicked
{
UIActionSheet *sheet;
// 判断是否支持相机
if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
{
sheet= [[UIActionSheet alloc] initWithTitle:@"选择图像" delegate:self cancelButtonTitle:nil destructiveButtonTitle:@"取消" otherButtonTitles:@"拍照", @"从相册选择", nil];
}
else {
sheet = [[UIActionSheet alloc] initWithTitle:@"选择图像" delegate:self cancelButtonTitle:nil destructiveButtonTitle:@"取消" otherButtonTitles:@"从相册选择", nil];
}
sheet.tag = 255;
[sheet showInView:self.view];
}
#pragma mark - action sheet delegte
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (actionSheet.tag == 255) {
NSUInteger sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
// 判断是否支持相机
if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
switch (buttonIndex) {
case 0:
return;
case 1: //相机
sourceType = UIImagePickerControllerSourceTypeCamera;
break;
case 2: //相册
sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
break;
}
}
else {
if (buttonIndex == 0) {
return;
} else {
sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
}
}
// 跳转到相机或相册页面
UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
imagePickerController.delegate = self;
imagePickerController.allowsEditing = YES;
imagePickerController.sourceType = sourceType;
[self presentViewController:imagePickerController animated:YES completion:^{}];
}
}
#pragma mark - image picker delegte
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
[picker dismissViewControllerAnimated:YES completion:^{}];
UIImage *image = [info objectForKey:UIImagePickerControllerEditedImage];
userImageView.image = image;
NSData *imageData = UIImageJPEGRepresentation(image, COMPRESSED_RATE);
UIImage *compressedImage = [UIImage imageWithData:imageData];
[HttpRequestManager uploadImage:compressedImage httpClient:self.httpClient delegate:self];
}
创建一张表单，选择相机或者相册，然后用回调函数处理返回的图片。
但是返回的图像并不是正方形，显示在用户头像的View里面产生明显的拉伸。研究了很久各种裁剪算法，甚至想创建一个view来处理。突然发现代码中从相机、相册获取图片时采用的的
UIImagePickerControllerOriginalImage
于是跟踪进去一看：
UIKIT_EXTERN NSString *const UIImagePickerControllerMediaType; // an NSString (UTI, i.e. kUTTypeImage)
UIKIT_EXTERN NSString *const UIImagePickerControllerOriginalImage; // a UIImage
UIKIT_EXTERN NSString *const UIImagePickerControllerEditedImage; // a UIImage
UIKIT_EXTERN NSString *const UIImagePickerControllerCropRect; // an NSValue (CGRect)
UIKIT_EXTERN NSString *const UIImagePickerControllerMediaURL; // an NSURL
UIKIT_EXTERN NSString *const UIImagePickerControllerReferenceURL NS_AVAILABLE_IOS(4_1); // an NSURL that references an
恍然大悟，很简单，用UIImagePickerControllerEditedImage，万事搞定。