WallpaperFragment.kt

package com.illuzor.lesson.wallpapers.screens

import android.os.Bundle
import androidx.lifecycle.ViewModelProviders
import com.illuzor.lesson.wallpapers.R
import com.illuzor.lesson.wallpapers.model.ViewModelWallpaper
import com.illuzor.lesson.wallpapers.model.ViewModelBase.State.*
import java.io.File

@Suppress("PrivatePropertyName")
class WallpaperFragment : AbstractFragment() {

    override val layoutId = R.layout.fragment_wallpaper

    private var loaded = false
    private lateinit var relativeUrl: String
    private lateinit var model: ViewModelWallpaper
    private lateinit var imageFile: File

    private val CACHE_SIZE = 20

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

        model = ViewModelProviders.of(this).get(ViewModelWallpaper::class.java)

        val filename = arguments!!.getString("filename", "")
        val category = arguments!!.getString("category", "")
        relativeUrl = "images/$category/$filename"
        createFile("$category-$filename")
    }

    private fun createFile(filename: String) {
        val subfolder = File(context!!.cacheDir.path + "/wallpapers/")
        imageFile = subfolder.resolve(filename)
        if (imageFile.exists()) return
        if (subfolder.exists() && subfolder.listFiles().size >= CACHE_SIZE) {
            subfolder.listFiles().forEach { it.delete() }
        } else {
            subfolder.mkdir()
        }
    }
}