Kotlin: Unresolved Reference for variable from instantiated class

Question

I make an ear training app and want the levels to be customizable. So I have a class with the same function for each of the 12 tones, so imagine setDb, setD, setEb etc.:

class MakeLevel(context: Context) {
    fun setC(something: Boolean): Boolean {
        var c = something
        return c
    }

I then instantiate the class in my main activity (FullscreenActivity):

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_fullscreen)
    makeLevel = MakeLevel(this)
}
companion object {
    lateinit var makeLevel: MakeLevel
}

Then in the fragment where the levels are selected, I do this:

override fun onResume() {
    super.onResume()
    majpentlevelbutton.setOnClickListener { view ->
        FullscreenActivity.makeLevel.setC(true)
        // [same for setD, setE, setG and setA, and false for all the other notes]
        view.findNavController().navigate(R.id.action_levelSelectFragment_to_chromaticFragment)
    }
}

Now here comes my problem: I want to access the value of c to determine whether ther sounds and the button for c should be loaded or not, and I can´t find a way to do so. For example, I´d like to use it like this:

if (c == true) {
    c_button.visibility = View.VISIBLE
}
else {
    c_button.visibility = View.GONE
}

I´ve tried c, makeLevel.c, FullscreenActivity.makeLevel.c and many more. Every time I get an Unresolved reference. So my question is how do I get a reference on the var c?

Rene · Accepted Answer · 2019-02-10 12:45:46Z

2

So far c is only a local variable within the method setC. If you need the value outside of the method you need to define a property:

class MakeLevel(context: Context) {
    var c = initValue
    fun setC(something: Boolean){
        c = something
    }
}

Now you can access this variable with: FullscreenActivity.makeLevel.c

answered Feb 10, 2019 at 12:45

Rene

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1 Comment

Alexey Romanov Over a year ago

Note: in this case there's no point to having a setC method, you just write FullscreenActivity.makeLevel.c = whatever.

Karthikeyan · Accepted Answer · 2019-02-10 13:24:14Z

0

Your problem is that you are trying to access a variable outside of its scope.

class MakeLevel(context: Context) {
    private var c = initValue

    fun setC(something: Boolean){
        c = something
    }

    fun getC(something: Boolean) {
        return c
    }

    if (getC() == true) 
        c_button.visibility = View.VISIBLE
    else 
       c_button.visibility = View.GONE
}

edited Feb 10, 2019 at 13:24

Karthikeyan

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answered Feb 10, 2019 at 13:02

BitcoinKing

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