Why does the reply send after two button clicks from the Second Activity to the Main Activity instead of one?

Question

This is the code for the activity_main.xml and MainActivity.kt:

<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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/reply_header"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="16dp"
        android:text=""
        android:textAppearance="@style/TextAppearance.AppCompat.Medium"
        android:textStyle="bold"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/reply_message"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:text=""
        android:textAppearance="@style/TextAppearance.AppCompat.Medium"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/reply_header" />

    <Button
        android:id="@+id/button_send"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="16dp"
        android:layout_marginBottom="16dp"
        android:text="Send"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />

    <EditText
        android:id="@+id/editText_send"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="16dp"
        android:hint="Type Message Here!"
        android:inputType="textLongMessage"
        android:text=""
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/button_send"
        app:layout_constraintStart_toStartOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

package com.example.twoactivities

import android.app.Activity
import android.content.Intent
import android.os.Bundle
import android.util.Log
import android.widget.Button
import android.widget.EditText
import android.widget.TextView
import androidx.activity.result.contract.ActivityResultContracts
import androidx.appcompat.app.AppCompatActivity

class MainActivity : AppCompatActivity() {

    private val secondActivityLauncher = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->

        if (result.resultCode == RESULT_OK) {
            val data: Intent? = result.data
            val replyMessage = data?.getStringExtra("REPLY_KEY_VALUE")

            if (replyMessage != null) {
                val headerTextView: TextView = findViewById(R.id.reply_header)
                val textView: TextView = findViewById(R.id.reply_message)
                textView.text = replyMessage
                headerTextView.text = "Reply Received"
            }
        }
    }

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

        //val replyMessage = intent.getStringExtra("REPLY_KEY_VALUE")
        //val replyHeader = intent.getStringExtra("REPLY_HEADER_VALUE")

        //val replyHeaderTextView: TextView = findViewById(R.id.reply_header)
        //val replyMessageTextView: TextView = findViewById(R.id.reply_message)

        //replyHeaderTextView.text = replyHeader
        //replyMessageTextView.text = replyMessage

        val mMessageEditText: EditText = findViewById(R.id.editText_send)
        val buttonSend: Button = findViewById(R.id.button_send)

        buttonSend.setOnClickListener {

            val secondActivityIntent = Intent(this, SecondActivity::class.java)

            val message = mMessageEditText.text.toString().trim()

            secondActivityIntent.putExtra("SEND_KEY_VALUE", message)

            startActivity(secondActivityIntent)

            secondActivityLauncher.launch(secondActivityIntent)
        }
    }
}

This is the code for the activity_second.xml and SecondActivity.kt

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".SecondActivity">

    <TextView
        android:id="@+id/text_header"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="16dp"
        android:text="Message Received"
        android:textAppearance="@style/TextAppearance.AppCompat.Medium"
        android:textStyle="bold"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/text_message"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:text=""
        android:textAppearance="@style/TextAppearance.AppCompat.Medium"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/text_header" />

    <Button
        android:id="@+id/button_reply"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="16dp"
        android:layout_marginBottom="16dp"
        android:text="Send"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />

    <EditText
        android:id="@+id/editText_reply"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="16dp"
        android:hint="Enter Your Reply Here"
        android:inputType="textLongMessage"
        android:text=""
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/button_reply"
        app:layout_constraintStart_toStartOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>
package com.example.twoactivities

import android.app.Activity
import android.content.Intent
import android.os.Bundle
import android.widget.Button
import android.widget.EditText
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity

class SecondActivity : AppCompatActivity() {

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

        setContentView(R.layout.activity_second)

        val message = intent.getStringExtra("SEND_KEY_VALUE")

        val textView: TextView = findViewById(R.id.text_message)

        textView.text = message

        val rReplyEditText: EditText = findViewById(R.id.editText_reply)
        val buttonReply: Button = findViewById(R.id.button_reply)

        buttonReply.setOnClickListener {

            val mainActivityIntent = Intent(this, MainActivity::class.java)

            //val replyHeader = "Reply Received"
            val replyMessage = rReplyEditText.text.toString().trim()

            //mainActivityIntent.putExtra("REPLY_HEADER_VALUE", replyHeader)
            mainActivityIntent.putExtra("REPLY_KEY_VALUE", replyMessage)

            setResult(RESULT_OK, mainActivityIntent)
            finish()

        }
    }
}

I have written some code here using the registerForActivityResult(ActivityResultContracts.StartActivityForResult()) method to send a reply from the Second Activity back to the Main Activity but when I click the "Send" button on Second Activity it doesn't send the reply I have typed out but when I click the button again regardless of whether I have typed nothing or a new reply it takes me to Main Activity and shows me the first message I typed. What could be the cause of this?

Answer 1

you're launching the SecondActivity twice in your MainActivity:

startActivity(secondActivityIntent)            // This starts the SecondActivity for the first time.
secondActivityLauncher.launch(secondActivityIntent)  // This starts the SecondActivity for the second time.

remove the first one