我可以在哪里存储我的应用程序的私有图像（内部存储之外）？

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I'm looking for solutions that are able to store private photos (can't be accessed by user or other apps) outside of my app's internal storage. If such a solution does not exist, I'd be interested in the next best approach.

Is there a place where I can store and manage my own images outside of internal storage? I don't want other apps to be able to see or access these images. Should I use external storage? Does such a place exist in the new MediaStore ? It's fine if they're deleted when the app is deleted.

This solution needs to support API 21 or higher.

I know there are a lot of questions like this, but they're 10+ years old and a lot has changed since then.

Use case / background

I have an app where all data is stored locally on the device (no external servers).

Users can choose custom background images for journal entries. A user could choose to use a different image for each journal entry they create. They can create as many journal entries as they want. They may revisit those journal entries. So, I need to store an unknown amount of images for the lifetime of the app. I've been saving a copy of the images the user picks from the gallery in my local app storage via context.filesDir .

I noticed a crash Fatal Exception: android.database.sqlite.SQLiteDiskIOException disk I/O error (code 4874 SQLITE_IOERR_SHMSIZE) and after googling, I found This error may indicate that the underlying filesystem volume is out of space.

My concern is that my app is running out of internal storage space because of the user images I'm storing.

Where should I be storing these images? I originally chose internal storage because I wanted my users' images to be reasonably private (since I don't know if they're storing sensitive images or not). I also wanted to make sure the images would always be available even if the source image (chosen from user's media) is deleted. However, I hadn't considered the limits imposed on internal storage. Silly me!

Answer 1

Android does not provide a place for you to store private photos (can't be accessed by user or other apps) outside of app's internal storage. I know you can contradict me by saying that one can store them in external storage by using getExternalStoragePublicDirectory() but the problem is that it is a shared directory accessible to users and other apps and remains when the app is deleted.

So I suggest you to use getFilesDir() as the directory returned by it is hidden from users and is deleted when the app is deleted. And also implement a image compressing tool in your app which automatically compresses images when uploaded by the user and then save it to internal storage. This won't solve the problem completely but I guess it's a start.

Answer 2

Darshil's answer is correct. Using the recommended Storage Access Framework for your use case, you should use getFilesDir() which will return your app's internal storage, which is private to your app.

Where should I be storing these images?

problem is due to limit of resource which is out of our control. However if you really want to store all the images, you can take some approaches:

1. Online: Use some cloud servers for storing user data. This might cost you a lot.

2. Offline: Tell user that you have only the limited amount of storage and storing more images will require to delete some older ones.

3. Both: Store in device. When internal storage is running low, tell user to buy some type of premium subscription to store unlimited cloud photos.

Answer 3

I would recommend checking out AWS Amplify which allows you to integrate your application with AWS services. For what you have described, you could use amplify to give your app the ability to authenticate users and set up cloud storage on AWS S3 which you can configure to only allow users to access and edit files that they have uploaded. One nice thing about AWS Amplify and AWS S3 cloud storage is that there is a free tier which allows you to develop your application for little to no cost. Depending on the amount of data that you will be uploading, it may be quite a while before you surpass the free tier limits.

A guide like this one may help you learn more.

Answer 4

With limited storage space appearing to be the root cause, I recommend intentionally using the UI to encourage users to use existing images over new images. (This can work in addition to the technical options provided in other answers)

For example, present the user with a list of available background images and a link to add a new image. In this case, using an existing image is 1 click with a preview, where getting a new image requires opening a new view and searching for the new image.

Using the UI in this way doesn't directly get you more space, but it can help you to more efficiently use the space you have by guiding users to use existing images. It also gives you a place to warn about (or limit) adding more images when there is not more space available.

*If you still must have more storage on the device outside of the app, you could try using the public space with encryption for "privacy".

Answer 5

I am not sure if I fully understand your question, but writing a quick tip. try cloud services to store your images like AWS s3, cloudinary. Cloudinary is much cheaper if you want to try like 25gb/month free.