Why does my game loop give me a blank screen?

In summary, the conversation is about a user who has used a game loop to alternate between two strings in a text view every two seconds, but is experiencing a blank screen. They are seeking help to figure out what could be causing the issue. The logcat shows that the process is not being handled and suggests that the user should not keep the loop running endlessly. They are also advised to consider the UI thread and not hold the code for a long time without releasing it periodically.
  • #1
Darkmisc
220
31
TL;DR Summary
I've used a game loop to try make a textView alternate between two different strings every two seconds. I just get a blank screen.
Hi everyone

I've used a game loop to try make a textView alternate between two different strings every two seconds. When I run it, I just get a blank screen. The textView was originally set to show "Hello World!" but not even that shows.

Does anyone know what's gone wrong?

Thanks

GameLoop: 
public void GameLoop() {
    double timeChange = 0;
    double time1 = System.nanoTime();
    double time2;

    while (true) {
        time2 = System.nanoTime();
        timeChange += (time2 - time1) / 1000000000;
        time1 = time2;
        textView.setText("fadsjfsdjfklsjfklsadjf");
        if (timeChange > 2) {
            textView.setText("2");
            timeChange = 0;
        }
    }
}
Logcat says:

logcat: 
 E  Not going to handle 'com.xxmassdeveloper.gamelooptest'!
2023-03-01 09:45:53.278  3598-3598  SDAgentPac...teReceiver pid-3598                             E  Not going to handle 'com.xxmassdeveloper.gamelooptest'!
---------------------------- PROCESS STARTED (25862) for package com.xxmassdeveloper.gamelooptest ----------------------------
2023-03-01 09:45:55.291 25862-25862 AppCompatDelegate       com.xxmassdeveloper.gamelooptest     D  Checking for metadata for AppLocalesMetadataHolderService : Service not found
2023-03-01 09:45:55.388 25862-25862 PhoneWindow             com.xxmassdeveloper.gamelooptest     D  forceLight changed to true [] from com.android.internal.policy.PhoneWindow.updateForceLightNavigationBar:4238 com.android.internal.policy.DecorView.updateColorViews:1510 com.android.internal.policy.PhoneWindow.dispatchWindowAttributesChanged:3216 android.view.Window.setFlags:1148 com.android.internal.policy.PhoneWindow.generateLayout:2444
2023-03-01 09:45:55.390 25862-25862 MultiWindowDecorSupport com.xxmassdeveloper.gamelooptest     I  updateCaptionType >> DecorView@2059f86[], isFloating: false, isApplication: true, hasWindowDecorCaption: false, hasWindowControllerCallback: true
2023-03-01 09:45:55.391 25862-25862 MultiWindowDecorSupport com.xxmassdeveloper.gamelooptest     D  setCaptionType = 0, DecorView = DecorView@2059f86[]
2023-03-01 09:45:55.626 25862-25862 er.gamelooptes          com.xxmassdeveloper.gamelooptest     W  Accessing hidden method Landroid/view/View;->computeFitSystemWindows(Landroid/graphics/Rect;Landroid/graphics/Rect;)Z (greylist, reflection, allowed)
2023-03-01 09:45:55.628 25862-25862 er.gamelooptes          com.xxmassdeveloper.gamelooptest     W  Accessing hidden method Landroid/view/ViewGroup;->makeOptionalFitsSystemWindows()V (greylist, reflection, allowed)
---------------------------- PROCESS ENDED (25862) for package com.xxmassdeveloper.gamelooptest ----------------------------
2023-03-01 09:47:39.554  3598-3598  SDAgentPac...teReceiver pid-3598                             E  Not going to handle 'com.xxmassdeveloper.gamelooptest'!
2023-03-01 09:47:39.786  3598-3598  SDAgentPac...teReceiver pid-3598                             E  Not going to handle 'com.xxmassdeveloper.gamelooptest'!
---------------------------- PROCESS STARTED (26539) for package com.xxmassdeveloper.gamelooptest ----------------------------
2023-03-01 09:47:41.959 26539-26539 AppCompatDelegate       com.xxmassdeveloper.gamelooptest     D  Checking for metadata for AppLocalesMetadataHolderService : Service not found
2023-03-01 09:47:42.042 26539-26539 PhoneWindow             com.xxmassdeveloper.gamelooptest     D  forceLight changed to true [] from com.android.internal.policy.PhoneWindow.updateForceLightNavigationBar:4238 com.android.internal.policy.DecorView.updateColorViews:1510 com.android.internal.policy.PhoneWindow.dispatchWindowAttributesChanged:3216 android.view.Window.setFlags:1148 com.android.internal.policy.PhoneWindow.generateLayout:2444
2023-03-01 09:47:42.044 26539-26539 MultiWindowDecorSupport com.xxmassdeveloper.gamelooptest     I  updateCaptionType >> DecorView@2059f86[], isFloating: false, isApplication: true, hasWindowDecorCaption: false, hasWindowControllerCallback: true
2023-03-01 09:47:42.044 26539-26539 MultiWindowDecorSupport com.xxmassdeveloper.gamelooptest     D  setCaptionType = 0, DecorView = DecorView@2059f86[]
2023-03-01 09:47:42.235 26539-26539 er.gamelooptes          com.xxmassdeveloper.gamelooptest     W  Accessing hidden method Landroid/view/View;->computeFitSystemWindows(Landroid/graphics/Rect;Landroid/graphics/Rect;)Z (greylist, reflection, allowed)
2023-03-01 09:47:42.237 26539-26539 er.gamelooptes          com.xxmassdeveloper.gamelooptest     W  Accessing hidden method Landroid/view/ViewGroup;->makeOptionalFitsSystemWindows()V (greylist, reflection, allowed)
---------------------------- PROCESS ENDED (26539) for package com.xxmassdeveloper.gamelooptest ----------------------------
 
Last edited by a moderator:
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  • #2
Darkmisc said:
Does anyone know what's gone wrong?
You can't just keep running forever - even game loops have to sleep sometimes!
 
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  • #3
UI thread will no resource to draw if you setText endless without quit the current method which is the same thread. And UI thread is not for holding your code for long time without release periodically.
 
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FAQ: Why does my game loop give me a blank screen?

Why does my game loop give me a blank screen?

One common reason for a blank screen in your game loop could be that you are not properly updating or rendering your game objects. Make sure that you are calling the necessary update and render functions within your game loop to display the game correctly.

How can I troubleshoot a blank screen in my game loop?

To troubleshoot a blank screen in your game loop, you can start by checking for any errors in your code. Make sure that all necessary variables are properly initialized and that there are no syntax errors. You can also use debugging tools to step through your code and see where the issue might be occurring.

Could a problem with my graphics library be causing a blank screen in my game loop?

Yes, a problem with your graphics library could be causing a blank screen in your game loop. Make sure that you have properly initialized your graphics library and that it is compatible with your game engine. Check for any errors or warnings related to the graphics library that could be impacting the rendering of your game.

Is my game loop running at the correct frame rate?

If your game loop is not running at the correct frame rate, it could result in a blank screen. Make sure that you are properly calculating the delta time and updating your game objects at the correct intervals. Adjusting the frame rate of your game loop could help resolve the issue of a blank screen.

Could a problem with my game assets be causing a blank screen in my game loop?

Yes, a problem with your game assets could be causing a blank screen in your game loop. Check that all necessary assets, such as images, sounds, and textures, are properly loaded and accessible within your game loop. Make sure that there are no errors or missing assets that could be preventing the game from rendering correctly.

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