相机与相册

调用系统相机和相册

添加权限描述：

或者直接在Info.plist中添加配置：

<key>NSPhotoLibraryAddUsageDescription</key>
<string>保存拍照需要该权限</string>
<key>NSPhotoLibraryUsageDescription</key>
<string>测试图库需要权限</string>
<key>NSCameraUsageDescription</key>
<string>测试相机需要权限</string>

图库动态权限请求：

• PHAuthorizationStatusNotDetermined：用户从未进行过授权等处理，首次访问相应内容会提示用户进行授权
• PHAuthorizationStatusRestricted：应用无权访问，且当前用户无法改变这个权限，比如:家长控制
• PHAuthorizationStatusDenied：用户拒绝访问
• PHAuthorizationStatusAuthorized：用户已授权，允许访问
• PHAuthorizationStatusLimited： 用户已授权此应用程序进行有限照片库访问（iOS14新增）

完整示例：

#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>
#import <Photos/Photos.h>

@interface ViewController ()<UIImagePickerControllerDelegate,UINavigationControllerDelegate>{
    UIImagePickerController *_picker;
}
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
}

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<UIImagePickerControllerInfoKey,id> *)info{
    [picker dismissViewControllerAnimated:YES completion:nil];
    UIImage *image = info[UIImagePickerControllerEditedImage];
    //    UIImage *image = info[UIImagePickerControllerOriginalImage];
    NSLog(@"%@",info);

  if ([picker sourceType] == UIImagePickerControllerSourceTypeCamera) {
    UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
  } 
}

- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo{
    NSLog(@"image = %@, error = %@, contextInfo = %@", image, error, contextInfo);
}

-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{
    [picker dismissViewControllerAnimated:YES completion:nil];
}

- (IBAction)onclick:(UIButton *)sender {
    switch (sender.tag) {
        case 1: // 打开相机
            [self openCamera];
            break;
        case 2: // 打开图库
            [self openPhotoLib];
            break;
        default:
            break;
    }
}

- (UIImagePickerController*)getPicker{
    if(_picker == nil){
        _picker = [[UIImagePickerController alloc]init];
        _picker.delegate = self;
        _picker.allowsEditing = YES;
    }
    return  _picker;
}

-(void)openPhotoLib{
    PHAuthorizationStatus status = [PHPhotoLibrary authorizationStatus];
    if(status == PHAuthorizationStatusNotDetermined){
        [PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status){
            NSLog(@"current thread is %@",[NSThread currentThread]);
            dispatch_async(dispatch_get_main_queue(), ^{
                if(status == PHAuthorizationStatusAuthorized){
                    [self openImagePicker];
                }
            });
        }];
    }else if (status == PHAuthorizationStatusDenied || status == PHAuthorizationStatusRestricted){
        UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil message:@"未获授权，请转到设置页面授权！" preferredStyle:UIAlertControllerStyleAlert];
        UIAlertAction *cancel = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel  handler:^(UIAlertAction * action){
            [self dismissViewControllerAnimated:YES completion:nil];
        }];
        UIAlertAction *setting = [UIAlertAction actionWithTitle:@"设置" style:UIAlertActionStyleDefault  handler:^(UIAlertAction * action){
            NSURL *url = [NSURL URLWithString: UIApplicationOpenSettingsURLString];
            if([[UIApplication sharedApplication] canOpenURL:url]){
                [[UIApplication sharedApplication] openURL:url options:@{} completionHandler:nil];
            }
        }];
        [alert addAction:cancel];
        [alert addAction:setting];
        [self presentViewController:alert animated:YES completion:nil];
    }else{
        [self openImagePicker];
    }
}

-(void)openImagePicker{
    UIImagePickerController *picker = [self getPicker];
    // 类型为图库
    picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    [self presentViewController:picker animated:YES completion:nil];
}

-(void)openCamera{
    AVAuthorizationStatus status = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
    if(status == AVAuthorizationStatusNotDetermined){
        // 首次请求用户授权
        [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted){
            dispatch_async(dispatch_get_main_queue(), ^{
                if(granted){
                    [self startCamera];
                }else{
                    NSLog(@"=========== 拒绝授权 ==========");
                }
            });
        }];
    }else if (status == AVAuthorizationStatusDenied){
        NSLog(@"=========== 未获得授权 ==========");
    }else{
        NSLog(@"=========== 已经授权 ==========");
        [self startCamera];
    }
}

-(void)startCamera{
    if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]){
        UIImagePickerController *picker = [self getPicker];
          // 类型为相机
        picker.sourceType = UIImagePickerControllerSourceTypeCamera;
        // 使用后置摄像头
        picker.cameraDevice = UIImagePickerControllerCameraDeviceRear;
        // 设置为拍照模式
        picker.cameraCaptureMode = UIImagePickerControllerCameraCaptureModePhoto;
        [self presentViewController:picker animated:YES completion:nil];
    }
}
@end

保存照片的处理：

• UIImageWriteToSavedPhotosAlbum：需要实现(void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo方法

• creationRequestForAssetFromImage：

  [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
      [PHAssetChangeRequest creationRequestForAssetFromImage:image];
  } completionHandler:^(BOOL success, NSError * _Nullable error) {
      NSLog(@"success = %d, error = %@", success, error);
  }];
  

以上两种方式保存照片，都会进行一定程度的压缩，可使用如下方式保存原始照片：

UIImage * imgsave = image;
// 将图片存储到本地沙盒中
NSString * path = [NSHomeDirectory() stringByAppendingString:@"/Documents/test.jpg"];
[UIImagePNGRepresentation(imgsave) writeToFile:path atomically:YES];

// 获取URL，根据URL将图片转存至图库
NSURL *imagePathUrl = [NSURL fileURLWithPath:path];

// 这里要先判断是否获取图库的权限，然后调用以下代码转存到图库
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
    [PHAssetChangeRequest creationRequestForAssetFromImageAtFileURL:imagePathUrl];
} completionHandler:^(BOOL success, NSError * _Nullable error) {
    if (success) NSLog(@"保存成功");
    else NSLog(@"保存失败");
}];

注意，启动的照片选择页面可能是英文的，如需显示为中文，则需要在Info.plist中配置一下，将值修改为china：

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