Cancel a command

[cpapplefamily]

Thank you. We will give this a go.

private boolean m_CancelCommand = false;

 

protected void initialize() { 
43     	m_CancelCommand = false; 
44     	// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 
45     	// Not Allow movement if Wrist Is up ! 
46     	// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 
47     	if(m_setpoint>70 && Robot.wristPID.getSetpoint()>30){ 
48     		System.out.println("Scissor Cancled Wrist > 30"); 
49     		m_CancelCommand = true; 
50     	}else{ 
51     		if(m_setpoint>30 && Robot.wristPID.getSetpoint()>55){ 
52     			System.out.println("Scissor Cancled Wrist > 55"); 
53         		m_CancelCommand = true; 
54         		 
55         	}else{ 
56         		
57         Robot.scissorPID.enable(); 
58         Robot.scissorPID.setSetpoint(m_setpoint); 
59 
 
60    
61         	} 
62     	}

72     protected boolean isFinished() { 
73       
74         return Robot.scissorPID.onTarget() || m_CancelCommand ; 
75 
 
76     
77     } 
78

[euhlmann]

Does Command.cancel() work?

[cpapplefamily]

We will try

this.Cancel()

but the JavaDocs say:

void edu.wpi.first.wpilibj.command.Command.cancel()


This will cancel the current command.

This will cancel the current command eventually. It can be called multiple times. And it can be called when the command is not running. If the command is running though, then the command will be marked as canceled and eventually removed.

A command can not be canceled if it is a part of a command group, you must cancel the command group instead.

In bold we are at this time! Unless just this command is canceled with in the Command Group.

[cpapplefamily]

Originally Posted by euhlmann

Does Command.cancel() work?

NOPE! Tested and since its in a cammand Group it crashed the program and sent an error to the councle. I'm not going to type it out but in a nut shell it said

....IllegalUseOfCommandException: Can not manually cancel a command in a command group....

But storing the status in m_CancelCommand and monitoring it in isFinished did work as we want it to.

[euhlmann]

Whoops, didn't see that section of the docs

There's an easy way to do what you want in your situation though.

public class ScissorToPosition extends Command {
  // ...
  
  boolean isUnsafe = false;

  public void initialize() {
    if(m_setpoint > 70 && Robot.wristPID.getSetpoint() > 30) { 
      System.out.println("Scissor canceled since wrist > 30"); 
      
      isUnsafe = true;
    } else {
      isUnsafe = false;
      
      // init as usual
    }
  }

  // ...

  public void execute() {
    if(isUnsafe) {
      return;
      // IMPORTANT. execute() will be called once regardless of isFinished() status
    }
    
    // execute as usual
  }

  public void isFinished() {
    if(isUnsafe) {
      return true;
    }
    
    return Robot.scissorPID.onTarget();
  }
}

[cpapplefamily]

Good to know I'll have them add that part to the code as well.

public void execute() {
if(isUnsafe) {
return;
// IMPORTANT. execute() will be called once regardless of isFinished() status
}

// execute as usual
}

[euhlmann]

Originally Posted by cpapplefamily

Good to know I'll have them add that part to the code as well.

The key part is in isFinished(), which returns true if it's unsafe (so the command finishes)

I'm curious as to why a command can't be canceled in a commandgroup. Is there any particular reason for that?

[cpapplefamily]

Originally Posted by euhlmann

The key part is in isFinished(), which returns true if it's unsafe (so the command finishes)

I'm curious as to why a command can't be canceled in a commandgroup. Is there any particular reason for that?

Right! Seems like you should be able to cancel a running command anywhere. maybe when its in a Command group its not its own object anymore. I guess for now we will just have to play by the rules.