Question Blank screen/UI disappearing

I'm working on an 2D game and designed my Login Screen. When I enter PlayMode, all my UI elements disappear and I have to manually uncheck and check the GameObject again, to make the UI visible. Same with building the APK for the game. UI ist visible and after compiling the APK, the UI is invisible again and also on the phone, the UI elemements are invisible. I didn't find something to fix this and I'm starting to get mad...

 

Sounds like you have a bug, and we know what that means!!

Time to start debugging! 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 for iOS: https://forum.unity.com/threads/how-to-capturing-device-logs-on-ios.529920/ or this answer for Android: https://forum.unity.com/threads/how-to-capturing-device-logs-on-android.528680/

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.

If your problem is with OnCollision-type functions, print the name of what is passed in!

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://forum.unity.com/threads/coroutine-missing-hint-and-error.1103197/#post-7100494

"When in doubt, print it out!(tm)" - Kurt Dekker (and many others)

Note: the

print()

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

Let me save you some time: I have been doing this for over four decades and getting mad never fixed a bug.

But by all means, if it helps you concentrate your fury, be my guest. Just beware of the negative health consequences of anger!

 

Thank you ALOT for your help! I'll try to find the problem while debugging. But I'm not 100% sure if this will fix it, because I already had this problem in another project some time ago without having a single script ready.

EDIT: See the Screenshot below. I just opened up the project and all UI elements are gone even if the "Login"-GameObject is active. Now I have to disable it and enable it again, to see my UI...

https://imgur.com/a/tdgOFIn (Can't post a picture)

 

Is it just UI anchoring / scaling? Find out right in the editor! Here's how:

Here are some notes on UI Anchoring, Scaling, CanvasScaler, etc:

https://forum.unity.com/threads/inc...size-between-two-people.1130146/#post-7261747

https://forum.unity.com/threads/game-ui-button-size-problem.1142650/#post-7337383

Usually you need to choose a suitable ScaleMode and MatchMode in the Canvas Scaler and stick with it 100%. Generally if you change those settings you will often need to redo your UI entirely.

I also use this

CanvasScalerOrientationDriver

utility to make sharing UI for Landscape / Portrait easier. Read what it does carefully.

https://gist.github.com/kurtdekker/8802b1b6c708637398f8c9167641efd3

 

I fixed it and it was the most stupid problem ever... My UI was just hidden by the background.....