Mobile App Dev 2021W: Tutorial 7

Code

MainActivity.kt

package carleton.comp1601.tapdemo

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.os.PersistableBundle
import android.util.Log
import android.view.View
import android.widget.TextView

class MainActivity : AppCompatActivity() {
    private lateinit var myMessage: TextView
    private var count = 0

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

        Log.d("TapDemo", "Created")

        myMessage = findViewById(R.id.myMessage)

        if (savedInstanceState != null) {
            with(savedInstanceState) {
                count = getInt("count")
            }
        } else {
            count = 0
        }
    }

    fun myButtonPressed(v: View) {
        count++
        myMessage.text = "You clicked $count times."

        Log.d("TapDemo", "Button Pressed")
    }

    override fun onSaveInstanceState(outState: Bundle) {
        outState.run {
            putInt("count", count)
        }
        super.onSaveInstanceState(outState)

        Log.d("TapDemo", "State saved")
    }

    override fun onDestroy() {
        super.onDestroy()
        Log.d("TapDemo", "Destroyed")
    }

    override fun onResume() {
        super.onResume()
        Log.d("TapDemo", "Resumed")
    }

    override fun onPause() {
        super.onPause()
        Log.d("TapDemo", "Paused")
    }

    override fun onStart() {
        super.onStart()
        Log.d("TapDemo", "Started")
    }

    override fun onStop() {
        super.onStop()
        Log.d("TapDemo", "Stopped")
    }

    override fun onRestart() {
        super.onRestart()
        Log.d("TapDemo", "Restarted")
    }
}

activity_main.xml

<syntaxhighlight lang="xml" line> <?xml version="1.0" encoding="utf-8"?> <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"

   xmlns:app="http://schemas.android.com/apk/res-auto"
   xmlns:tools="http://schemas.android.com/tools"
   android:id="@+id/TapDemo"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context=".MainActivity">

   <Button
       android:id="@+id/myButton"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:onClick="myButtonPressed"
       android:text="Tap me!"
       android:textAppearance="@style/TextAppearance.AppCompat.Display1"
       app:layout_constraintBottom_toTopOf="@+id/myMessage"
       app:layout_constraintEnd_toEndOf="parent"
       app:layout_constraintStart_toStartOf="parent"
       app:layout_constraintTop_toTopOf="parent" />

   <TextView
       android:id="@+id/myMessage"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:text="You haven't tapped yet."
       android:textAppearance="@style/TextAppearance.AppCompat.Display1"
       app:layout_constraintBottom_toBottomOf="parent"
       app:layout_constraintLeft_toLeftOf="parent"
       app:layout_constraintRight_toRightOf="parent"
       app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout> </syntaxhiglight>