In FLUTTER I'm trying to refresh screen 4 times. I've 4 variable 1 Elevated button and if statement. It's changing image for imagePath1, imagePath2, imagePath3 variable but not working for imagePath4 variable.

Here is my variable.

    String imagepath1 = 'images/flame-833.png';
String imagepath2 = 'images/flame-859.png';
String imagepath3 = 'images/flame-891.png';
String imagepath4 = 'images/flame-4.png';
String currentPath = imagePath1;

Here is my ElevatedButton with if statement and Image widget.

ElevatedButton(
        onPressed: () {
          setState(() {
            if (currentPath == imagePath1) {
              currentPath = imagePath2;
            } else if (currentPath == imagepath2) {
              currentPath = imagepath3;
            } else if (currentPath == imagepath3) {
              currentPath = imagepath4;
            } else {
              currentPath = imagepath1;
            }
          });
        },
        child: const Text('Add Image'),
      ),
      Center(child: Image.asset(currentPath)),

1. Once I go to this page I get imagePath1 picture.
2. Once I click Add image I get imagePath2 picture.
3. Once I click Add image 2nd time I get imagePath3 picture.
4. Once I click Add image 3rd time I do not get any picture. No screen change.

CodePudding user response：

your code works perfectly, the only problem is that the variables have to be instantiated outside the Widget build

class _TesteScreenState extends State<TesteScreen> {
  String imagepath1 = 'images/flame-833.png';
  String imagepath2 = 'images/flame-859.png';
  String imagepath3 = 'images/flame-891.png';
  String imagepath4 = 'images/flame-4.png';
  String currentPath = 'images/flame-833.png';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        children: [
          ElevatedButton(
            onPressed: () {
              setState(() {
                if (currentPath == imagepath1) {
                  currentPath = imagepath2;
                } else if (currentPath == imagepath2) {
                  currentPath = imagepath3;
                } else if (currentPath == imagepath3) {
                  currentPath = imagepath4;
                } else {
                  currentPath = imagepath1;
                }
              });
            },
            child: const Text('Add Image'),
          ),
          Center(child: Image.asset(currentPath)),
        ],
      ),
    );
  }
}

CodePudding user response：

Finally I find the solution. Only problem was variable name uppercase and lowercase. But I do not know why flutter did not identify this error.

Here is correct variable names code:

    String imagePath1 = 'images/flame-833.png';
String imagePath2 = 'images/flame-859.png';
String imagePath3 = 'images/flame-891.png';
String imagePath4 = 'images/flame-4.png';
String currentPath = imagePath1;

Here is widget code:

ElevatedButton(
        onPressed: () {
          setState(() {
            if (currentPath == imagePath1) {
              currentPath = imagePath2;
            } else if (currentPath == imagePath2) {
              currentPath = imagePath3;
            } else if (currentPath == imagePath3) {
              currentPath = imagePath4;
            } else {
              currentPath = imagePath1;
            }
          });
        },
        child: const Text('Add Image'),
      ),
      Center(child: Image.asset(currentPath)),