如何解决Function1中的Function1（上下文）不能应用于（）

Question

I have the following problems:

I would like to call a function from another class so I added this line of code

Function1 func = new Function1(); and I get an error saying

Function1 (Context) in Function1 cannot be applied to ()

Furthermore, relating to this function and its error, I intend calling the aforementioned function which takes a JSON object and a Filename as parameters and it returns a file, however, when I enter it, I get the following error

Wrong 2nd argument type, found Java.lang.String required Java.io.File

The code in question is this:

JSONObject export = jsonArray1.getJSONObject(index);

 File file = func.exportToFile(export, "Export.json");

The fuction in question starts like this:

public void exportToFile(JSONObject objectToExport, File fN)
    {
        String output = objectToExport.toString();
        file_ = fN;
        if (!file_.exists()) {
            try {
                file_.createNewFile();
               } catch (IOException e) {
            e.printStackTrace();
        }
    }
    try{
        FileOutputStream fOut = new FileOutputStream(file_);
        fOut.write(output.getBytes());
        fOut.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

}

NB: I have tried to call the function like this:

File file = func.exportToFile(export, func.file);

but I only get the error saying incompatible types

Required Java.io.file

Found Void

What have I done wrong?

Answer 1

this func.exportToFile(export, func.file); will not return anything since exportToFile it's a void method .

change your method to make it return file this way :

public File exportToFile(JSONObject objectToExport, File fN) {
  String output = objectToExport.toString();
  file_ = fN;
  if (!file_.exists()) {
        try {
          file_.createNewFile();
        } catch (IOException e) {
          e.printStackTrace();
        }
  }
  try{
    FileOutputStream fOut = new FileOutputStream(file_);
    fOut.write(output.getBytes());
    fOut.close();
    return file_;
  } catch (FileNotFoundException e) {
    e.printStackTrace();
  } catch (IOException e) {
    e.printStackTrace();
  }
  return null;
}