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Variable not updating properly - debugging guide

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VH

VariableHelper_Pro

Posted on July 26, 2025 • Beginner

🔧 Variable not updating when buttons are pressed

Hi everyone! I’m having a really frustrating bug with my action system. I have arrow buttons and a sleep button that should change my ‘action’ variable, but only the sleep button works properly. 😞

When I press the arrow buttons, the variable doesn’t seem to update at all. I’ve checked my code multiple times but can’t figure out what’s wrong.

Project link: My Action System Project (wait until after the intro to find the buttons)

Any help would be amazing! This is driving me crazy! 🙏

DB

DebugMaster_Sarah

Replied 25 minutes later • ⭐ Best Answer

I see this problem all the time @VariableHelper_Pro! This is a classic case of conflicting scripts. Here’s what’s happening and how to fix it:

🔍 The Problem: Script Conflicts

Your issue is likely caused by multiple scripts running at the same time, overriding each other:

flowchart TD A[🖱️ User Clicks Button] --> B[Button Script Runs] B --> C[Set Action = 'Right'] D[🔄 Other Scripts Running] --> E[Forever Loop Checking] E --> F{Mouse Not Touching?} F -->|Yes| G[Set Action = 'Idle'] C --> H[Variable = 'Right'] G --> I[Variable = 'Idle'] H --> J{Which Happens Last?} I --> J J --> K[❌ Usually 'Idle' Wins] style A fill:#e1f5fe style C fill:#e8f5e8 style G fill:#ffcdd2 style K fill:#f8bbd9

🚀 Solution 1: Proper Button Logic

❌ Problematic Code (causes conflicts):

    // Button sprite - BAD approach
forever
if <touching [mouse-pointer v]?> then
set [brightness v] effect to [20]
if <mouse down?> then
set [Action v] to [Right]
end
else
set [brightness v] effect to [0]
set [Action v] to [Idle]  // This keeps overriding!
end
end

✅ Fixed Code (much better!):

    // Button sprite - GOOD approach
forever
if <touching [mouse-pointer v]?> then
set [brightness v] effect to [20]
if <mouse down?> then
set [Action v] to [Right]
broadcast [action changed v]
end
else
set [brightness v] effect to [0]
// Don't automatically set to Idle here!
end
end

🎯 Solution 2: Centralized Action Management

Create one main script to handle all action changes:

    // Main sprite or stage - Action Manager
when flag clicked
set [Action v] to [Idle]
set [Action Timer v] to [0]

forever
if <(Action Timer) > [0]> then
change [Action Timer v] by [-1]
else
if <not <(Action) = [Idle]>> then
set [Action v] to [Idle]
end
end
end

when I receive [action changed v]
set [Action Timer v] to [30]  // Action lasts 0.5 seconds

🔧 Solution 3: Better Button Design

Use this pattern for each button sprite:

    // Right Arrow Button
when flag clicked
forever
if <touching [mouse-pointer v]?> then
set [brightness v] effect to [20]
else
set [brightness v] effect to [0]
end
end

when this sprite clicked
set [Action v] to [Right]
broadcast [action changed v]
wait [0.1] seconds  // Prevent double-clicks

🎮 Solution 4: Keyboard Alternative

Sometimes keyboard controls work better than buttons:

    when [right arrow v] key pressed
set [Action v] to [Right]
broadcast [action changed v]

when [left arrow v] key pressed
set [Action v] to [Left]
broadcast [action changed v]

when [up arrow v] key pressed
set [Action v] to [Jump]
broadcast [action changed v]

when [space v] key pressed
set [Action v] to [Sleep]
broadcast [action changed v]

🔍 Debugging Tips

Here’s how to debug variable issues:

Add Debug Display:

    // Create a text sprite for debugging
when flag clicked
forever
set [text v] to (join [Action: ] (Action))
go to x: [-200] y: [150]
end

Use Say Blocks for Testing:

    when this sprite clicked
say [Button clicked!] for [1] seconds
set [Action v] to [Right]
say (join [Action set to: ] (Action)) for [1] seconds

Check Script Execution:

    // Add this to see which scripts are running
when flag clicked
forever
say [Main loop running] for [0.1] seconds
wait [1] seconds
end

⚡ Advanced Solution: State Machine

For complex projects, use a state machine approach:

    define handle action (new_action)
if <not <(Action) = (new_action)>> then
set [Previous Action v] to (Action)
set [Action v] to (new_action)
broadcast (join [action_] (new_action))
end

// Use this instead of directly setting variables
when this sprite clicked
handle action [Right]

The key is to avoid having multiple scripts that can change the same variable at the same time. Use broadcasts and centralized management instead! 🎯

VH

VariableHelper_Pro

Replied 1 hour later

@DebugMaster_Sarah OMG this is exactly what I needed! 🎉

I implemented the centralized action management and it works perfectly now! I had no idea that multiple scripts could interfere with each other like that. The debug display was super helpful too - I could actually see the variable changing back and forth!

Thank you so much for the detailed explanation! 🙏

CT

CodeTeacher_Mike

Replied 2 hours later

Great solution @DebugMaster_Sarah! 👏 This is a perfect example of why understanding program flow is so important.

For beginners reading this: always remember that in Scratch, multiple scripts can run at the same time. This is powerful but can cause conflicts if you’re not careful. The key principles are:

  • 🎯 One source of truth - Have one place that manages each variable
  • 📡 Use broadcasts - Let scripts communicate instead of fighting
  • 🔍 Debug visually - Use say blocks and text displays to see what’s happening
VB

Vibelf_Community

Pinned Message • Moderator

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