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
207
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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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