很多应用中我门需要用到iOS设备的摄像头进行拍照，视频等，并且从相册中选取我们需要的图片或者视频。这时就可以使用UIImagePickerController类来完成控制。
一、UIImagePickerController类
UIImagePickerController 这个类可以为大家提供照相的功能,以及图片,视频浏览的功能。
二、检查硬件是否安装有摄像头或者允许操作相册
1、 判断摄像头是否可用
（1） 判断设备是否有摄像头
－ (BOOL) isCameraAvailable{
return [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];
}
（2） 前面的摄像头是否可用
－ (BOOL) isFrontCameraAvailable{
return [UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceFront];
}
（3） 后面的摄像头是否可用
－ (BOOL) isRearCameraAvailable{
return [UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear];
}
2、 判断支持的媒体类型
// 判断是否支持某种多媒体类型：拍照，视频,
－(BOOL)cameraSupportsMedia:(NSString*)paramMediaType sourceType:(UIImagePickerControllerSourceType)paramSourceType{
__block BOOL result=NO;
if ([paramMediaType length]==0) {
NSLog(@"Media type is empty.");
return NO;
}
NSArray*availableMediaTypes=[UIImagePickerController availableMediaTypesForSourceType:paramSourceType];
[availableMediaTypes enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSString *mediaType = (NSString *)obj;
if ([mediaType isEqualToString:paramMediaType]){
result = YES;
*stop= YES;
}
}];
return result;
}
（1） 检查摄像头是否支持录像
－ (BOOL) doesCameraSupportShootingVideos{
/*在此处注意我们要将MobileCoreServices 框架添加到项目中，
然后将其导入：#import <MobileCoreServices/MobileCoreServices.h> 。不然后出现错误使用未声明的标识符 'kUTTypeMovie'
*/
return [self cameraSupportsMedia:( NSString *)kUTTypeMovie sourceType:UIImagePickerControllerSourceTypeCamera];
}
（2）检查摄像头是否支持拍照
－(BOOL) doesCameraSupportTakingPhotos{
/*在此处注意我们要将MobileCoreServices 框架添加到项目中，
然后将其导入：#import <MobileCoreServices/MobileCoreServices.h> 。不然后出现错误使用未声明的标识符 'kUTTypeImage'
*/
return [self cameraSupportsMedia:( NSString *)kUTTypeImage sourceType:UIImagePickerControllerSourceTypeCamera];
}
3、相册文件选取相关
（1）相册是否可用
－(BOOL) isPhotoLibraryAvailable{
return [UIImagePickerController isSourceTypeAvailable: UIImagePickerControllerSourceTypePhotoLibrary];
}
（2） 是否可以在相册中选择视频
－ (BOOL) canUserPickVideosFromPhotoLibrary{
return [self cameraSupportsMedia:( NSString *)kUTTypeMovie sourceType:UIImagePickerControllerSourceTypePhotoLibrary];
}
（3）是否可以在相册中选择照片
－ (BOOL) canUserPickPhotosFromPhotoLibrary{
return [self cameraSupportsMedia:( NSString *)kUTTypeImage sourceType:UIImagePickerControllerSourceTypePhotoLibrary];
}
三、用摄像头进行拍照和录像功能
1、假设我门点击一个按钮调用摄像头进行拍照和录像功能
－ (void)ClickControlAction:(id)sender{
// 判断有摄像头，并且支持拍照功能
if ([self isCameraAvailable] && [self doesCameraSupportTakingPhotos]){
// 初始化图片选择控制器
UIImagePickerController *controller = [[UIImagePickerController alloc] init];
/*设置媒体来源，即调用出来的UIImagePickerController所显示出来的界面，有一下三种来源
typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {
UIImagePickerControllerSourceTypePhotoLibrary,
UIImagePickerControllerSourceTypeCamera,
UIImagePickerControllerSourceTypeSavedPhotosAlbum
};分别表示：图片列表，摄像头，相机相册*/
[controller setSourceType:UIImagePickerControllerSourceTypeCamera];
// 设置所支持的媒体功能，即只能拍照，或则只能录像，或者两者都可以
NSString *requiredMediaType = ( NSString *)kUTTypeImage;
NSString *requiredMediaType1 = ( NSString *)kUTTypeMovie;
NSArray *arrMediaTypes=[NSArray arrayWithObjects:requiredMediaType, requiredMediaType1,nil];
[controller setMediaTypes:arrMediaTypes];
// 设置录制视频的质量
[controller setVideoQuality:UIImagePickerControllerQualityTypeHigh];
//设置最长摄像时间
[controller setVideoMaximumDuration:10.f];
// 设置是否可以管理已经存在的图片或者视频
[controller setAllowsEditing:YES];
// 设置代理
[controller setDelegate:self];
[self presentViewController:controller animated:YES completion:nil];
}else {
NSLog(@"Camera is not available.");
}
}
2、保存成功之后，调用相关代理方法
// 保存图片后到相册后，调用的相关方法，查看是否保存成功
- (void) imageWasSavedSuccessfully:(UIImage *)paramImage didFinishSavingWithError:(NSError *)paramError contextInfo:(void *)paramContextInfo{
if (paramError == nil){
NSLog(@"Image was saved successfully.");
} else {
NSLog(@"An error happened while saving the image.");
NSLog(@"Error = %@", paramError);
}
}
// 当得到照片或者视频后，调用该方法
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
NSLog(@"Picker returned successfully.");
NSLog(@"%@", info);
NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
// 判断获取类型：图片
if ([mediaType isEqualToString:( NSString *)kUTTypeImage]){
UIImage *theImage = nil;
// 判断，图片是否允许修改
if ([picker allowsEditing]){
//获取用户编辑之后的图像
theImage = [info objectForKey:UIImagePickerControllerEditedImage];
} else {
// 照片的原数据
theImage = [info objectForKey:UIImagePickerControllerOriginalImage];
}
// 保存图片到相册中
SEL selectorToCall = @selector(imageWasSavedSuccessfully:didFinishSavingWithError:contextInfo:);
UIImageWriteToSavedPhotosAlbum(theImage, self,selectorToCall, NULL);
}else if ([mediaType isEqualToString:(NSString *)kUTTypeMovie]){
// 判断获取类型：视频
//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
// Assets Library 框架包是提供了在应用程序中操作图片和视频的相关功能。相当于一个桥梁，链接了应用程序和多媒体文件。
ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init];
// 将视频保存到相册中
[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);
}
}];
}
[picker dismissViewControllerAnimated:YES completion:nil];
}
// 当用户取消时，调用该方法
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{
[picker dismissViewControllerAnimated:YES completion:nil];
}
四、从相册获取图片和视频数据
- (void)ClickShowPhotoAction:(id)sender{
if ([self isPhotoLibraryAvailable]){
UIImagePickerController *controller = [[UIImagePickerController alloc] init];
[controller setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];// 设置类型
NSMutableArray *mediaTypes = [[NSMutableArray alloc] init];
if ([self canUserPickPhotosFromPhotoLibrary]){
[mediaTypes addObject:( NSString *)kUTTypeImage];
}
if ([self canUserPickVideosFromPhotoLibrary]){
[mediaTypes addObject:( NSString *)kUTTypeMovie];
}
[controller setMediaTypes:mediaTypes];
[controller setDelegate:self];// 设置代理
[self.navigationController presentViewController:controller animated:YES completion:nil];
}
}
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