Упражнение 10. Диалози, файлове

//MainActivity

import android.content.Intent
import android.graphics.Color
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.EditText
import android.widget.TextView
import androidx.appcompat.app.AlertDialog

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }

    fun btn_message(view: View) {
        val dlg=AlertDialog.Builder(this)
        dlg.setTitle("Здравейте")
        dlg.setMessage("Това е съобщение ...")
        dlg.setPositiveButton("Затвори",null)

        dlg.show()
    }

    fun btn_dialog(view: View){
        val dlg=AlertDialog.Builder(this)
        dlg.setTitle("Изход")
        dlg.setMessage("Сигурни ли сте?")
        dlg.setPositiveButton("Да") { dialog, which ->
            finish()
        }
        dlg.setNegativeButton("Не") { dialog, which ->

        }
        dlg.show()
    }

    fun btn_trialog(view:View) {
        val tv=findViewById<TextView>(R.id.textView)

        val dlg=AlertDialog.Builder(this)
        dlg.setTitle("Изберете ")
        dlg.setMessage("Цвят за текста")
        dlg.setPositiveButton("Син") { dialog, which ->
            tv.setBackgroundColor(Color.BLUE)
        }
        dlg.setNegativeButton("Червен") { dialog, which ->
            tv.setBackgroundColor(Color.RED)
        }
        dlg.setNeutralButton("Жълт") { dialog, which ->
            tv.setBackgroundColor(Color.YELLOW)
        }

        dlg.show()
    }

    fun btn_izbor(view: View) {
        val tv=findViewById<TextView>(R.id.textView)

        val elementi= arrayOf("Първи","Втори","Трети","Четвърти")
        val dlg=AlertDialog.Builder(this)
        dlg.setTitle("Изберете ")
        dlg.setItems(elementi) {dialog, which ->
            when(which) {
                0->tv.setBackgroundColor(Color.CYAN)
                1->tv.setBackgroundColor(Color.GREEN)
                2->tv.setBackgroundColor(Color.MAGENTA)
                3->tv.setBackgroundColor(Color.YELLOW)
            }
        }
        dlg.setPositiveButton("Затвори", null)
        dlg.show()
    }

    fun btn_ekran(view: View) {
        val dlg=AlertDialog.Builder(this)
        dlg.setTitle("Нов екран")
        dlg.setView(R.layout.activity_dialog_ekran)
        val dialog_view=layoutInflater.inflate(R.layout.activity_dialog_ekran,null)
        val ed=dialog_view.findViewById<EditText>(R.id.editTextTextPersonName)
        dlg.setPositiveButton("Затвори" ) { dialog, which ->
            val tv=findViewById<TextView>(R.id.textView)
            tv.text=ed.text.toString()
        }
        dlg.show()
    }

    fun btn_start(view: View) {
        val start=Intent(this, Dogs::class.java)
        startActivity(start)
    }
}
// Dogs.kt
import android.net.Uri
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.ImageView
import android.widget.TextView
import android.widget.Toast
import java.io.File
import java.util.*


class Dogs : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_dogs)
        val rnd= Random()
// Случайно число в интервала 1..3
        val index=rnd.nextInt(3)+1
// Папка във вирталното устройство съдържащи 6 файла, 3 txt и 3 jpg
        val path="data/data/com.example.upr10/Files/"

        if( File(path+"d"+index+".txt").exists() ) {
            var txt=""
            File(path+"d"+index+".txt").useLines { lines ->
                lines.forEach {
                    txt=txt+it
                }
            }
            findViewById<TextView>(R.id.textView2).text=txt
            findViewById<ImageView>(R.id.imageView).
            setImageURI(Uri.fromFile(File(path+"/d"+index+".jpg")))
        } else {
            Toast.makeText(this, "File not found", Toast.LENGTH_SHORT).show()
        }
    }
}