iOS7 Programming Cookbook 第十五章学习笔记

####Detecting and Probing the Camera

#import <MobileCoreServices/MobileCoreServices.h>
#import <AssetsLibrary/AssetsLibrary.h>

@implementation AppDelegate

- (BOOL) isCameraAvailable{
    
    return [UIImagePickerController isSourceTypeAvailable:
            UIImagePickerControllerSourceTypeCamera];
    
}

- (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 obj, NSUInteger idx, BOOL *stop) {
         
         NSString *mediaType = (NSString *)obj;
         if ([mediaType isEqualToString:paramMediaType]){
             result = YES;
             *stop= YES;
         }
         
     }];
    
    return result;
    
}

- (BOOL) doesCameraSupportShootingVideos{
    
    return [self cameraSupportsMedia:(__bridge NSString *)kUTTypeMovie
                          sourceType:UIImagePickerControllerSourceTypeCamera];
    
}

- (BOOL) doesCameraSupportTakingPhotos{
    
    return [self cameraSupportsMedia:(__bridge NSString *)kUTTypeImage
                          sourceType:UIImagePickerControllerSourceTypeCamera];
    
}


- (BOOL) isFrontCameraAvailable{
    //UIImagePickerController类管理可定制,系统提供的用户界面支持拍照和电影设备,和选择保存图片和电影在你的应用程序使用
    //isCameraDeviceAvailable 相机设备可用
    //UIImagePickerControllerCameraDeviceFront 指定设备的相机在前面。
    return [UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceFront];
    
}

- (BOOL) isRearCameraAvailable{
    
    return [UIImagePickerController
            isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear];
    
}

- (BOOL) isFlashAvailableOnFrontCamera{
    
    return [UIImagePickerController isFlashAvailableForCameraDevice:
            UIImagePickerControllerCameraDeviceFront];
    
}

- (BOOL) isFlashAvailableOnRearCamera{
    
    return [UIImagePickerController isFlashAvailableForCameraDevice:
            UIImagePickerControllerCameraDeviceRear];
    
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
    
    //前置摄像头
    if ([self isFrontCameraAvailable]){
        NSLog(@"The front camera is available.");
        if ([self isFlashAvailableOnFrontCamera]){
            NSLog(@"The front camera is equipped with a flash");
        } else {
            NSLog(@"The front camera is not equipped with a flash");
        }
    } else {
        NSLog(@"前置摄像头不可用");
    }
    
    //后置摄像头
    if ([self isRearCameraAvailable]){
        NSLog(@"The rear camera is available.");
        if ([self isFlashAvailableOnRearCamera]){
            NSLog(@"The rear camera is equipped with a flash");
        } else {
            NSLog(@"The rear camera is not equipped with a flash");
        }
    } else {
        NSLog(@"后置摄像头不可用");
    }
    
    if ([self doesCameraSupportTakingPhotos]){
        NSLog(@"The camera supports taking photos.");
    } else {
        NSLog(@"相机不支持拍照");
    }
    
    if ([self doesCameraSupportShootingVideos]){
        NSLog(@"The camera supports shooting videos.");
    } else {
        NSLog(@"相机不支持视频拍摄。");
    }
    
    self.window = [[UIWindow alloc] initWithFrame:
                   [[UIScreen mainScreen] bounds]];
    
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];
    return YES;
}

@end

Reference

• O’Reilly Shop iOS 7 Programming Cookbook