• 用到state machine的概念，需要去記前一個按鈕的狀態是甚麼

public class TeleOpMode extends TeleOp_Base{
    boolean buttonA_state = false;
    @Override
    public void runOpMode() throws InterruptedException {
        init_hardware();
        waitForStart();
        while(opModeIsActive()) {
            if(gamepad1.a) {
                buttonA_state = true;
            }
            else if(buttonA_state && !gamepad1.a) {
                //馬達轉90度
                buttonA_state = false;
            }
        }
    }
}

• 若你想把它寫成function(ButtonAPressedOnce( ))

public class TeleOpMode extends TeleOp_Base{
    boolean buttonA_state = false;
    @Override
    public void runOpMode() throws InterruptedException {
        init_hardware();
        waitForStart();
        while(opModeIsActive()) {
            if(ButtonAPressedOnce()) {
                //馬達轉90度
            }
        }
    }
    public boolean ButtonAPressedOnce() {
        if(gamepad1.a) {
            buttonA_state = true;
        }
        else if(buttonA_state && !gamepad1.a) {
						buttonA_state = false;
            return true;
        }
        return false;
    }
}