关于iOS中简单实现调用系统相机及相册功能

「爱情、让人受尽委屈。」 2022-06-17 06:59 378阅读 0赞

在iOS中要拍照和录制视频最简单的方式就是调用UIImagePickerController，UIImagePickerController继承与UINavigationController，需要使用代理方法时需要同时遵守这两个协议，以前可能比较多的是使用UIImagePickerController来选择相册图片或者拍摄图片，其实它的功能还能用来拍摄视频。

使用UIImagePickerController拍照或者拍视频主要以下几个步骤：

*  创建一个全局的UIImagePickerController对象。
 *  指定UIImagePickerController的来源sourceType，是来自UIImagePickerControllerSourceTypeCamera相机，还是来自UIImagePickerControllerSourceTypePhotoLibrary相册。
 *  然后是设置mediaTypes媒体类型，这是录制视频必须设置的选项，默认情况下是kUTTypeImage（注意：mediaTypes的设置是在MobileCoreServices框架下），同还可以设置一些其他视频相关的属性，例如：videoQuality视频的质量、videoMaximumDuration视频的最大录制时长（默认为10s），cameraDevice摄像头的方向（默认为后置相机）。
 *  指定相机的捕获模式cameraCaptureMode，设置mediaTypes后在设置捕获模式，注意的是捕获模式需要在相机来源sourceType为相机时设置，否则会出现crash。
 *  适时的展示UIImagePickerController，然后在相应的代理方法保存和获取图片或视频。

下面还是上代码吧，更加清晰明了...  
首先需要导入以下用到的几个头文件，同时遵守两个代理方法

#import "ViewController.h"
    #import <MobileCoreServices/MobileCoreServices.h>
    #import <AVFoundation/AVFoundation.h>
    #import <MediaPlayer/MediaPlayer.h>
    @interface ViewController ()<UIImagePickerControllerDelegate, UINavigationControllerDelegate>
    {
        UIImagePickerController *_imagePickerController;
    }

创建UIImagePickerController对象

- (void)viewDidLoad {
        [super viewDidLoad];
        // Do any additional setup after loading the view, typically from a nib
    
        _imagePickerController = [[UIImagePickerController alloc] init];
        _imagePickerController.delegate = self;
        _imagePickerController.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
        _imagePickerController.allowsEditing = YES;

从摄像头获取图片或视频

#pragma mark 从摄像头获取图片或视频
    - (void)selectImageFromCamera
    {
        _imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
        //录制视频时长，默认10s
        _imagePickerController.videoMaximumDuration = 15;
    
        //相机类型（拍照、录像...）字符串需要做相应的类型转换
        _imagePickerController.mediaTypes = @[(NSString *)kUTTypeMovie,(NSString *)kUTTypeImage];
    
        //视频上传质量
        //UIImagePickerControllerQualityTypeHigh高清
        //UIImagePickerControllerQualityTypeMedium中等质量
        //UIImagePickerControllerQualityTypeLow低质量
        //UIImagePickerControllerQualityType640x480
        _imagePickerController.videoQuality = UIImagePickerControllerQualityTypeHigh;
    
        //设置摄像头模式（拍照，录制视频）为录像模式
        _imagePickerController.cameraCaptureMode = UIImagePickerControllerCameraCaptureModeVideo;
        [self presentViewController:_imagePickerController animated:YES completion:nil];
    }

从相册获取图片或视频

#pragma mark 从相册获取图片或视频
    - (void)selectImageFromAlbum
    {
        //NSLog(@"相册");
        _imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    
        [self presentViewController:_imagePickerController animated:YES completion:nil];
    }

在imagePickerController:didFinishPickingMediaWithInfo:代理方法中处理得到的资源，保存本地并上传...

#pragma mark UIImagePickerControllerDelegate
    //该代理方法仅适用于只选取图片时
    - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(nullable NSDictionary<NSString *,id> *)editingInfo {
        NSLog(@"选择完毕----image:%@-----info:%@",image,editingInfo);
    }

//适用获取所有媒体资源，只需判断资源类型
    - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info{
        NSString *mediaType=[info objectForKey:UIImagePickerControllerMediaType];
        //判断资源类型
        if ([mediaType isEqualToString:(NSString *)kUTTypeImage]){
            //如果是图片
            self.imageView.image = info[UIImagePickerControllerEditedImage];
            //压缩图片
            NSData *fileData = UIImageJPEGRepresentation(self.imageView.image, 1.0);
            //保存图片至相册
            UIImageWriteToSavedPhotosAlbum(self.imageView.image, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
            //上传图片
            [self uploadImageWithData:fileData];
    
        }else{
            //如果是视频
            NSURL *url = info[UIImagePickerControllerMediaURL];
            //播放视频
            _moviePlayer.contentURL = url;
            [_moviePlayer play];
            //保存视频至相册（异步线程）
            NSString *urlStr = [url path];
    
            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
                if (UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(urlStr)) {
    
                    UISaveVideoAtPathToSavedPhotosAlbum(urlStr, self, @selector(video:didFinishSavingWithError:contextInfo:), nil);
                }
            });
            NSData *videoData = [NSData dataWithContentsOfURL:url];
            //视频上传
            [self uploadVideoWithData:videoData];
        }
        [self dismissViewControllerAnimated:YES completion:nil];
    }

图片和视频保存完毕后的回调

#pragma mark 图片保存完毕的回调
    - (void) image: (UIImage *) image didFinishSavingWithError:(NSError *) error contextInfo: (void *)contextInf{
    
    }
    
    #pragma mark 视频保存完毕的回调
    - (void)video:(NSString *)videoPath didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInf{
        if (error) {
            NSLog(@"保存视频过程中发生错误，错误信息:%@",error.localizedDescription);
        }else{
            NSLog(@"视频保存成功.");
        }
    }

以上仅是简单功能的实现，还有例如切换前后摄像头、闪光灯设置、对焦、曝光模式等更多功能...