iOS 拍照(相机)/相册获取图片

iOS 从相机/相册获取图片的文章很多,本文也并没有对系统的相册/相机界面做多少优化.只是从程序健壮性,用户体验的角度对我以往的代码进行封装优化

首先,demo地址:https://github.com/sun6762/getPicture.git

准备工作
a. 要能使真机在使用时成功调用相册/拍照功能必须在info.plist,添加
Privacy - Camera Usage Description & Privacy - Photo Library Usage Description,当然,在测试的时候根据提示添加更好

b. 要使用imgPickerController的代理必须有UIImagePickerControllerDelegate, UINavigationControllerDelegate2个代理

@interface ViewController ()<UIImagePickerControllerDelegate, UINavigationControllerDelegate> 
@end

用户开启相机权限

 // 引入以下2个类
#import <AVFoundation/AVCaptureDevice.h>
#import <AVFoundation/AVMediaFormat.h>

AVAuthorizationStatus avStatus = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];

//  avStatus 的4中类型
/*
AVAuthorizationStatusNotDetermined  // 初次调用
AVAuthorizationStatusRestricted //  禁用
AVAuthorizationStatusDenied // 
AVAuthorizationStatusAuthorized // 开通权限
*/

// 用户开放相机权限后 判断相机是否可用
BOOL useable = [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];

用户开启相册权限,跟上述过程相似

// 导入此类
#import <Photos/Photos.h>

PHAuthorizationStatus phStatus = [PHPhotoLibrary authorizationStatus];
// 同样 phStatus 有4中类型
/*
     PHAuthorizationStatusNotDetermined = 0
     PHAuthorizationStatusRestricted
     PHAuthorizationStatusDenied
     PHAuthorizationStatusAuthorized
     */

// 判断相册权限
[UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]

打开相机/相册

// 打开相机/相册
- (void)openSuccWith:(NSString *)flag{
    
    UIImagePickerController *photoPicker = [UIImagePickerController new];
    photoPicker.delegate = self;
    photoPicker.allowsEditing = NO;
    
    if ([flag isEqualToString:AV]) {
        photoPicker.sourceType = UIImagePickerControllerSourceTypeCamera;
        
    }
    if ([flag isEqualToString:PH]) {
        photoPicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    }
    
    [self presentViewController:photoPicker animated:YES completion:nil];
}

用户关闭iOS拍照/相册权限,引导用户打开拍照/相册权限

- (void)guideUserOpenAuth{
    
    UIAlertController *alertC = [UIAlertController alertControllerWithTitle:@"温馨提示" message:@"请打开访问权限" preferredStyle:(UIAlertControllerStyleAlert)];
    UIAlertAction *alertA = [UIAlertAction actionWithTitle:@"确定" style:(UIAlertActionStyleDefault) handler:nil];
    UIAlertAction *act = [UIAlertAction actionWithTitle:@"去设置" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        // 引导用户设置
        NSURL *url = [NSURL URLWithString:UIApplicationOpenSettingsURLString];
        
        if ([[UIApplication sharedApplication] canOpenURL:url]) {
            
            [[UIApplication sharedApplication] openURL:url options:@{} completionHandler:nil];
        }
    }];
    [alertC addAction:alertA];
    [alertC addAction:act];
    [self presentViewController:alertC animated:YES completion:nil];
}

UIImagePickerControllerDelegate

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info{
    NSString *mediaType=[info objectForKey:UIImagePickerControllerMediaType];
    
    if ([mediaType isEqualToString:@"public.image"]) {
        UIImage * image;
        // 判断，图片是否允许修改
        if ([picker allowsEditing]){
            //获取用户编辑之后的图像
            image = [info objectForKey:UIImagePickerControllerEditedImage];
        } else {
            // 照片的元数据参数
            image = [info objectForKey:UIImagePickerControllerOriginalImage];
        }
        
        // 压缩图片
        UIImage *compressImg = [self compressPictureWith:image];
        self.imgView.image = compressImg;
        //        NSLog(@"%@",NSStringFromCGSize(compressImg.size));
        // 用于上传
        NSData *tmpData = UIImageJPEGRepresentation(compressImg, 0.5);
        
    }
    [self dismissViewControllerAnimated:YES completion:NULL];
}

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

我们获取的图片上传到服务器,都需要图片压缩,这也有,是不是很贴心

/ 压缩图片
- (UIImage *)compressPictureWith:(UIImage *)originnalImage{
    CGFloat ruleWidth = 600;
    if (originnalImage.size.width < ruleWidth) {
        return originnalImage;
    }
    
    CGFloat hight = ruleWidth/originnalImage.size.width * originnalImage.size.height;
    CGRect rect = CGRectMake(0, 0, ruleWidth, hight);
    // 开启图片上下文
    UIGraphicsBeginImageContext(rect.size);
    // 将图片渲染到图片上下文
    [originnalImage drawInRect:rect];
    // 获取图片
    UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
    // 关闭图片上下文
    UIGraphicsEndImageContext();
    return img;
}

....
以后有时间再将打开界面优化一下