BaseFragment.kt

package com.example.githubfirebaseissue.base

import android.app.Dialog
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.view.Window
import android.widget.TextView
import android.widget.Toast
import androidx.fragment.app.Fragment
import com.example.githubfirebaseissue.R
import okio.IOException
import retrofit2.HttpException


abstract class BaseFragment : Fragment() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
    }

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ) = inflater.inflate(getLayoutRes(), container, false)


    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        viewInitialization(view)
    }

    fun showToast(message: String) {
        Toast.makeText(context, message, Toast.LENGTH_SHORT).show()
    }

    protected fun showErrorDialog(message: String, actionText: String) {
        val dialog = Dialog(requireContext())
        with(dialog) {
            requestWindowFeature(Window.FEATURE_NO_TITLE)
            setCancelable(false)
            setContentView(R.layout.error_layout)
        }
        val title = dialog.findViewById(R.id.txt_message) as TextView

        val action = dialog.findViewById(R.id.txt_action) as TextView
        title.text = message
        action.text = actionText
        action.setOnClickListener {
            dialog.dismiss()
            activity?.onBackPressed()
        }
        dialog.show()
    }

    protected fun handleError(th: Throwable) {
        val error = when (th) {
            is HttpException -> when (th.code()) {
                401 -> getString(R.string.error_unauthorized)
                500 -> getString(R.string.error_server)
                else -> getString(R.string.error_server)
            }
            is IOException -> getString(R.string.internet_error)
            else -> getString(R.string.error_server)
        }
        onError(error)
    }

    /**
     * This method is called after view has been created.
     * This method should be used to initialize all views that are needed to be created (and recreated after fragment is reattached)
     * @param view The root view of the fragment
     */
    abstract fun viewInitialization(view: View)

    abstract fun getLayoutRes(): Int
    abstract fun showLoadingState(loading: Boolean)
    abstract fun onError(message: String)

}