[bobcroucher]

You can either create a new tiny class specifically to be used as your PIDOutput class, or you can have your robot class be that class too by using a line like this on your Robot class definition.

public class Robot extends SampleRobot implements PIDOutput {

Then you need to implement pidWrite() which tells the PID what you want to do with the output.

In your case, copying a line from above I assume you will want this:

@Override
  /* This function is invoked periodically by the PID Controller, */
  /* based upon navX-MXP yaw angle input and PID Coefficients.    */
  
public void pidWrite(double output) {
      Drive( output, 1.0 );
}

If the error between your setpoint and the gyro angle was 90 degrees or more you would want full 1.0 power, so I would start with a P constant of 1.0 / 90. So 0.01 should be a good starting place.

When you set your gyro up, here are some other suggestions straight from their example:

      turnController.setInputRange(-180.0f,  180.0f);
      turnController.setOutputRange(-1.0, 1.0);
      turnController.setAbsoluteTolerance(2.0);
      turnController.setContinuous(true);

Last, if you are trying to go to 0, then call

turnController.setSetpoint( 0.0 );

and to turn the controller on use,

turnController.enable();