title: Flutter logic issue
body: <p>I'm building this small game , it's similar to Qix game .</p>
  <p>I already built the first screens now i need to implement the functionality  , the car should be moving using the buttons , and while moving it should draw like a container behind it until it feel all the stadium .</p>
  <p>this is where I'm making the car moves :</p>
  <pre><code>class _GameScreenState extends State&lt;GameScreen&gt; {
    double xPosition = Random().nextInt(230).toDouble();
    double yPposition = Random().nextInt(200).toDouble();
    @override
    Widget build(BuildContext context) {
      return Scaffold(
        body: SafeArea(
          child: Container(
            height: MediaQuery.of(context).size.height,
            width: MediaQuery.of(context).size.width,
            decoration: BoxDecoration(
              image: DecorationImage(
                image: AssetImage(&quot;assets/images/bg.png&quot;),
                fit: BoxFit.cover,
              ),
            ),
            child: Column(
              children: [
                // Game play
                Expanded(
                  flex: 6,
                  child: Stack(
                    children: [
                      Container(
                        height: MediaQuery.of(context).size.height,
                        width: MediaQuery.of(context).size.width,
                        color: Colors.transparent,
                      ),
                      Positioned(
                        bottom: yPposition,
                        left: xPosition,
                        child: Image.asset(&quot;assets/images/car.png&quot;),
                      )
                    ],
                  ),
                ),
                // Player inputes
                Expanded(
                  child: Container(
                    child: Padding(
                      padding: const EdgeInsets.all(8.0),
                      child: Row(
                        mainAxisAlignment: MainAxisAlignment.spaceBetween,
                        children: [
                          Row(
                            children: [
                              RoundIconButton(
                                onPress: () {
                                  setState(() {
                                    yPposition--;
                                  });
                                },
                                icon: Icons.arrow_downward,
                              ),
                              RoundIconButton(
                                onPress: () {
                                  setState(() {
                                    yPposition++;
                                  });
                                },
                                icon: Icons.arrow_upward,
                              ),
                            ],
                          ),
                          Row(
                            children: [
                              RoundIconButton(
                                onPress: () {
                                  setState(() {
                                    xPosition--;
                                  });
                                },
                                icon: Icons.arrow_back,
                              ),
                              RoundIconButton(
                                onPress: () {
                                  setState(() {
                                    xPosition = xPosition + 10;
                                  });
                                },
                                icon: Icons.arrow_forward,
                              ),
                            ],
                          ),
                        ],
                      ),
                    ),
                  ),
                ),
              ],
            ),
          ),
        ),
      );
    }
  }
  </code></pre>
  <p>I also need the car keep moving when I press the button , in my case it moves only one time</p>