Why do textures turn black when I close the app?

Question

Java

When you exit the application with the android "back" system button and then enter the application, all textures are replaced with black rectangles. Why does this happen and how to avoid it?

Answer 1

In android openGL, when folding, all textures are unloaded from video memory. When you turn, you need to restore them. You can also try caching and restoring from the cache.

Answer 2

First you need to understand where you get "pictures" for textures from and how you load them into a texture.
libgdx has a concept of managed and unmanaged textures.
Managed textures restore themselves. Such textures are usually loaded from the assets directory and libgdx itself reloads images into textures on restore.
You control unmanaged textures.
If the textures are dynamic, for example, you get pictures from the Internet, then you need to store the original Pixmap or Bitmap separately in memory from which you will update the texture again when restoring.