Can't access variable in data class kotlin-CodePudding

why can't I access a variable from another class? (the variable is in the data class, and when I want to access it, it throws "unresolved reference")

Here's what It looks like:

The code that tries to access the variable:


import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.TextView

class questionActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_question)
        var nameDisplay: TextView = findViewById(R.id.nameDisplay)
        var name2 = usernameStore.username //here's the error, the "username" thing is red
        nameDisplay.setText(name2)

    }
}

The data Class:

package com.ketchup.myquizzies

public data class usernameStore (
   var username: String
)

Any help appreciated guys, I literally searched all things that came to my mind to solve this, but I couldn't help myself :(

Android Studio, Kotlin

CodePudding user response：

usernameStore is a class, not an object. You need to create an instance of usernameStore to be able to use it.

class questionActivity : AppCompatActivity() {
    val store = usernameStore()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_question)
        var nameDisplay: TextView = findViewById(R.id.nameDisplay)
        var name2 = store.username
        nameDisplay.setText(name2)

    }
}

FWIW, creating instances of classes is covered by this section of this chapter of this free book.

CodePudding user response：

You have not created instance of class

usernameStore

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.TextView

class questionActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_question)
    var nameDisplay: TextView = findViewById(R.id.nameDisplay)
   // replace with below code
    var name2 = usernameStore().username
    nameDisplay.setText(name2)

 }
}