StartActivityForResult in Android.

 

Useful Video : https://youtu.be/AD5qt7xoUU8


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<?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=".MainActivity">

    <EditText
        android:id="@+id/number1_editText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="90dp"
        android:layout_marginTop="213dp"
        android:ems="10"
        android:hint="Number 1"
        android:inputType="textPersonName"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/number2_editText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="51dp"
        android:ems="10"
        android:hint="Number 2"
        android:inputType="textPersonName"
        app:layout_constraintStart_toStartOf="@+id/number1_editText"
        app:layout_constraintTop_toBottomOf="@+id/number1_editText" />

    <TextView
        android:id="@+id/Result_textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="54dp"
        android:layout_marginBottom="69dp"
        android:text="Result"
        android:textSize="30dp"
        app:layout_constraintBottom_toTopOf="@+id/number1_editText"
        app:layout_constraintStart_toStartOf="@+id/number1_editText" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="72dp"
        android:layout_marginEnd="14dp"
        android:onClick="OpenActivityTwo"
        android:text="Open Activity 2"
        app:layout_constraintEnd_toEndOf="@+id/number2_editText"
        app:layout_constraintTop_toBottomOf="@+id/number2_editText" />
</androidx.constraintlayout.widget.ConstraintLayout>



package com.deepesh.startactivityforresultapp;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    public static final int REQUEST_CODE=1;
    TextView result_textview;
    EditText number1_ed , number2_ed;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        result_textview = findViewById(R.id.Result_textview);
        number1_ed = findViewById(R.id.number1_editText);
        number2_ed = findViewById(R.id.number2_editText);

    }

    // user clicks button
    public void OpenActivityTwo(View view) {

        Intent intent = new Intent(this,Activity2.class);
        intent.putExtra("number1",Integer.valueOf(number1_ed.getText().toString()));
        intent.putExtra("number2",Integer.valueOf(number2_ed.getText().toString()));

        //REQUEST_CODE is needed for Confirmation.
        startActivityForResult(intent,REQUEST_CODE);

    }

    // CALLED WHEN THE ACTIVITY2 COMES BACK
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode==REQUEST_CODE && resultCode==RESULT_OK){
            int result = data.getIntExtra("result",0);
            result_textview.setText(String.valueOf(result));
        }else{
            Log.d("TAG", "onActivityResult: USER CANCELLED OR CLICKED THE BACK BUTTON");
        }
    }
}







<?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=".Activity2">

    <TextView
        android:id="@+id/number_displayer"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="136dp"
        android:text="TextView"
        android:textSize="30sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/add_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="3dp"
        android:layout_marginBottom="51dp"
        android:onClick="AddNumbers"
        android:text="Add"
        app:layout_constraintBottom_toTopOf="@+id/sub_button"
        app:layout_constraintEnd_toEndOf="@+id/sub_button" />

    <Button
        android:id="@+id/sub_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="142dp"
        android:onClick="SubtractNumbers"
        android:text="Subtract"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>


package com.deepesh.startactivityforresultapp;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class Activity2 extends AppCompatActivity {

    TextView number_displayer;
    int number1;
    int number2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_2);

        number_displayer = findViewById(R.id.number_displayer);

        Intent intent = getIntent();
        number1 = intent.getIntExtra("number1", 0);
        number2 = intent.getIntExtra("number2", 0);

        number_displayer.setText("NUMBERS : " + number1 + "," + number2);

    }

    // user clicks add button
    public void AddNumbers(View view) {

        Intent intent = new Intent();
        intent.putExtra("result", number1 + number2);

        // If the user cancels or Clicks the BACK button , Request code send from the system is RESULT_CANCEL
        setResult(RESULT_OK, intent);
        finish();
    }

    // user clicks sub button
    public void SubtractNumbers(View view) {

        Intent intent = new Intent();
        intent.putExtra("result", number1 - number2);

        setResult(RESULT_OK, intent);
        finish();
    }


}




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