Flutter ElevatedButton doesn't respond

Question

I have an application with a form and now with a little experimental refactoring from last week 2 buttons doesn't do anything.

Logging just say "button was click " but no method is called.

The code is :

Widget build() {
///...
ElevatedButton (
   onPress : genText1(),
   child : Text("add text for image 1")
),
///...
}

An error is detected here in a method called by genText1()

Uint8List? genText2(int index, Uint8List image) {
final appState = Provider.of<AppState>(context, listen: false);
log.info(
  "GenText2 dart method. Starting process... invoke generateText (Kotlin)",
);
log.info(
  "GenText2 dart method. Starting process... Inputs : checks if not null",
);
try {
  var image2 = Image.memory(image);
  var width = image2.width;
  var height = image2.height;
  var imageBytes = image;
  var imageWidth = width;
  var imageHeight = height;

  if (imageWidth != null && imageHeight != null) {
    try {
      final Map<String, dynamic> arguments = {
        'image': imageBytes,
        'width': imageWidth, // <-- ADD THIS
        'height': imageHeight, // <-- ADD THIS
      };
      Future<dynamic> result = _FirstPanelState._channel.invokeMethod(
        'generateText',
        arguments,
      );
      log.info(
        "GenText2 dart method. Starting process... generateText invoked (return to Dart)",
      );
      // Handle cases where imageBytes, imageWidth, or imageHeight might be null
      result.then((value) {
        if (value != null) {
          var value2 = value as Uint8List;
          log.info(
            "GenText2 dart method. treats return value (not null...)",
          );
          setState(() {
            switch (index) {
              case 1:
                log.info(
                  "GenText2 dart method. treats return value set textFileContent1 $value",
                );
                appState.textFileContent1 = value2;
                break;
              case 2:
                log.info(
                  "GenText2 dart method. treats return value set textFileContent1 $value",
                );
                appState.textFileContent2 = value2;
                break;
              case 3:
                log.info(
                  "GenText2 dart method. treats return value set textFileContent1 $value",
                );
                appState.textFileContent3 = value2;
                break;

              default:
            }
            ScaffoldMessenger.of(context).showSnackBar(
              SnackBar(content: Text('Completed with 100% no error. ')),
            );

            //appState.selectedImage = Image.memory(value);
          });
        }
      }).catchError((error) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Error: $error')),
        );
      });
    } on PlatformException catch (e) {
      log.severe("Failed to generate text: '${e.message}'.");
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Failed to generate text. Error: $e')),
      );
    }
  } else {
    log.info("Error: imageWidth or imageHeight is null.");
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text('Error: imageWidth or imageHeight is null.')),
    );
  }
} on PlatformException catch (e) {
  ScaffoldMessenger.of(context).showSnackBar(
    SnackBar(content: Text('Error: $e')),
  );
  log.fine("Platform Error Code: ${e.code}");
  log.fine("Platform Error Message: ${e.message}");
  log.fine(
    "Platform Error Details: ${e.details}",
  ); // Now will be a String or a Map
  // If you sent a Map, you can process it like this:
  if (e.details is Map) {
    final errorDetails = e.details as Map;
    log.fine("Error Size: ${errorDetails["size"]}");
    log.fine("Error Message: ${errorDetails["message"]}");
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text( "Error Size: ${errorDetails["size"]}\nError Message: ${errorDetails["message"]}"
      ),
    ));
  }
}
return null;

}

Error: imageWidth or imageHeight is null.

Zahra · Accepted Answer · 2025-09-27 13:37:39Z

3

The problem is that you are not correctly calling the genText1() method in the onPressed, the correct way is like:

ElevatedButton(
              child: const Text("Ok"),
              onPressed: () {
                genText1();
              },
            )

or another way of passing methods:

ElevatedButton(
              child: const Text("Ok"),
              onPressed: genText1,
            )

answered Sep 27 at 13:37

Zahra

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Comments

MNBLabs · Accepted Answer · 2025-10-01 08:34:06Z

The main issue with your ElevatedButton is that you are calling the function immediately instead of passing it as a callback. In Flutter, the onPressed property expects a function reference, not the result of a function call.

What you have done:

ElevatedButton(
  onPress: genText1(),  // This calls genText1 immediately when the widget builds
  child: Text("add text for image 1"),
),

What you should do:

ElevatedButton(
  onPressed: genText1,  // Pass the function reference here
  child: Text("add text for image 1"),
),

Corrected image dimension extraction `example`:

Future<Uint8List?> genText2(int index, Uint8List image) async {
  final appState = Provider.of<AppState>(context, listen: false);
  try {
    final ui.Image decodedImage = await getImageFromBytes(image);
    final int width = decodedImage.width;
    final int height = decodedImage.height;

    final Map<String, dynamic> arguments = {
      'image': image,
      'width': width,
      'height': height,
    };

    final result = await _FirstPanelState._channel.invokeMethod('generateText', arguments);

    if (result != null) {
      final value2 = result as Uint8List;
      setState(() {
        switch (index) {
          case 1:
            appState.textFileContent1 = value2;
            break;
          case 2:
            appState.textFileContent2 = value2;
            break;
          case 3:
            appState.textFileContent3 = value2;
            break;
        }
      });
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Completed with 100% no error.')),
      );
      return value2;
    }
  } catch (e) {
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text('Error: $e')),
    );
  }
  return null;
}

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Corrected image dimension extraction `example`:

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