How to Load an Image from an url And Save it on Android

Unity Engine
,
1

Hello, How are you?

This is my objective, I need to load an image from an URL from Remote Config. But a twist to this assignment was that we were to save the image we loaded from the URL. If there was an internet connection then the can be loaded from the URL but if there I no internet connection then the last saved image should be displayed.

This was my script but the problem is it does not work on Android

using System.Collections;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.Networking;

public class ImageDownloader : MonoBehaviour
{
    public string imageUrl = "https://example.com/image.jpg";
    public void Initialize()
    {
        this.gameObject.GetComponent<Image>().sprite = Resources.Load<Sprite>(Application.dataPath + "/Assets/BackgroundImage.png");
    }

    public IEnumerator DownloadAndSaveImage()
    {
        UnityWebRequest request = UnityWebRequestTexture.GetTexture(imageUrl);
        yield return request.SendWebRequest();

        if (request.result != UnityWebRequest.Result.Success)
        {
            Debug.LogError("Failed to download image: " + request.error);
            yield break;
        }
        else{
            Texture2D texture = DownloadHandlerTexture.GetContent(request);
            byte[] imageBytes = texture.EncodeToPNG();
            Destroy(texture);

            string savePath = Application.dataPath + "/Assets/BackgroundImage.png";
            System.IO.File.WriteAllBytes(savePath, imageBytes);
            Sprite downloadedSprite = LoadSpriteFromPath(savePath);
            this.gameObject.GetComponent<Image>().sprite = downloadedSprite;

            Debug.Log("Image downloaded and saved to: " + savePath);
        }

       
    }
    private Sprite LoadSpriteFromPath(string imagePath)
    {
        byte[] imageBytes = System.IO.File.ReadAllBytes(imagePath);
        Texture2D texture = new Texture2D(2, 2);
        if (texture.LoadImage(imageBytes))
        {
            Sprite sprite = Sprite.Create(texture, new Rect(0, 0, texture.width, texture.height), Vector2.one * 0.5f);
            return sprite;
        }
        else
        {
            Debug.LogError("Failed to load image as Sprite: " + imagePath);
            return null;
        }
    }

    private void Start()
    {
        StartCoroutine(DownloadAndSaveImage());
    }
}

This works great in the editor but when I build it to an app and tested it, it does not change the image when changing the URL on Remote Config.

Please help, Thanks

2

Time to start debugging it on the device!

Here is how you can begin your exciting new debugging adventures:

You must find a way to get the information you need in order to reason about what the problem is.

Once you understand what the problem is, you may begin to reason about a solution to the problem.

What is often happening in these cases is one of the following:

  • the code you think is executing is not actually executing at all
  • the code is executing far EARLIER or LATER than you think
  • the code is executing far LESS OFTEN than you think
  • the code is executing far MORE OFTEN than you think
  • the code is executing on another GameObject than you think it is
  • you’re getting an error or warning and you haven’t noticed it in the console window

To help gain more insight into your problem, I recommend liberally sprinkling Debug.Log() statements through your code to display information in realtime.

Doing this should help you answer these types of questions:

  • is this code even running? which parts are running? how often does it run? what order does it run in?
  • what are the names of the GameObjects or Components involved?
  • what are the values of the variables involved? Are they initialized? Are the values reasonable?
  • are you meeting ALL the requirements to receive callbacks such as triggers / colliders (review the documentation)

Knowing this information will help you reason about the behavior you are seeing.

You can also supply a second argument to Debug.Log() and when you click the message, it will highlight the object in scene, such as Debug.Log("Problem!",this);

If your problem would benefit from in-scene or in-game visualization, Debug.DrawRay() or Debug.DrawLine() can help you visualize things like rays (used in raycasting) or distances.

You can also call Debug.Break() to pause the Editor when certain interesting pieces of code run, and then study the scene manually, looking for all the parts, where they are, what scripts are on them, etc.

You can also call GameObject.CreatePrimitive() to emplace debug-marker-ish objects in the scene at runtime.

You could also just display various important quantities in UI Text elements to watch them change as you play the game.

Visit Google for how to see console output from builds. If you are running a mobile device you can also view the console output. Google for how on your particular mobile target, such as this answer or iOS: https://discussions.unity.com/t/700551 or this answer for Android: https://discussions.unity.com/t/699654

If you are working in VR, it might be useful to make your on onscreen log output, or integrate one from the asset store, so you can see what is happening as you operate your software.

Another useful approach is to temporarily strip out everything besides what is necessary to prove your issue. This can simplify and isolate compounding effects of other items in your scene or prefab.

Here’s an example of putting in a laser-focused Debug.Log() and how that can save you a TON of time wallowing around speculating what might be going wrong:

https://discussions.unity.com/t/839300/3

“When in doubt, print it out!™” - Kurt Dekker (and many others)

Note: the print() function is an alias for Debug.Log() provided by the MonoBehaviour class.

3

Thanks for your reply, then it time to begin debugging.