如何在iPhone相机胶卷上取回已保存的图片？ [英] How do I get back a saved picture on iPhone camera roll?

问题描述

我是iOS开发的新手，我正在尝试创建一个允许用户使用相机拍照的视图。

I am new to iOS development and am trying to create a view that will allow the user to take a picture using their camera.

我想要发生的是当用户拍摄照片时，它会将其保存到相机胶卷中。我相信可以通过以下声明简单地完成：

What I want to happen is when the user has taken the picture, it saves it to their camera roll. I believe that can be simply accomplished by the following statement:

//Let's say the image you want to save is in a UIImage called "imageToBeSaved"
UIImageWriteToSavedPhotosAlbum(imageToBeSaved, nil, nil, nil);

但是，我的问题是，如果用户离开视图然后返回到它，我仍然希望图片在那里。那么我如何取回之前拍摄/保存的相同图片，以便在重新打开视图时重新加载？

However, my question is, if the user leaves the view and then returns to it I still want that picture to be there. So how do I get back the same picture I have just taken/saved previously, so I can reload it when they reopen the view?

任何帮助都会很棒！谢谢。

Any help would be great! Thank you.

推荐答案

void UIImageWriteToFile(UIImage *image, NSString *fileName)
{
    NSArray *dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentDirectoryPath = dirPaths[0];
    NSString *filePath = [documentDirectoryPath stringByAppendingPathComponent:fileName];

    NSData *imageData = UIImagePNGRepresentation(image);
    [imageData writeToFile:filePath atomically:YES];
}

void UIImageReadFromFile(UIImage **image, NSString *fileName)
{
    NSArray *dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentDirectoryPath = dirPaths[0];
    NSString *filePath = [documentDirectoryPath stringByAppendingPathComponent:fileName];

    image = [UIImage imageWithContentsOfFile:filePath];
}

图像将保存到应用程序包的Documents目录中并从中读取指定名称。

Image will be saved to and read from the Documents directory of your app's bundle with specified name.

用法示例：

UIImageWriteToFile(image, @"somephoto.png");

UIImage *fetchedImage;
UIImageReadFromFile(&fetchedImage, @"somephoto.png");

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