Full project with source code When we open another activity, we can send data to it by using an intent and putExtra. But what if we also want to get something back? This is what the startActivityForResult method is for.
By opening our child activity with this method and overriding onActivityResult we can send data back to our parent activity after we set it with setResult in our child activity before we close it
Activity2.java
package tech.codingpoint.startactivityforresultexample;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class Activity2 extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_2);
setTitle("Activity 2");
Intent intent = getIntent();
final int number1 = intent.getIntExtra("number1", 0);
final int number2 = intent.getIntExtra("number2", 0);
TextView textViewNumbers = findViewById(R.id.text_view_numbers);
textViewNumbers.setText("Numbers: " + number1 + ", " + number2);
Button buttonAdd = findViewById(R.id.button_add);
Button buttonSubtract = findViewById(R.id.button_subtract);
buttonAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int result = number1 + number2;
Intent resultIntent = new Intent();
resultIntent.putExtra("result", result);
setResult(RESULT_OK, resultIntent);
finish();
}
});
buttonSubtract.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int result = number1 - number2;
Intent resultIntent = new Intent();
resultIntent.putExtra("result", result);
setResult(RESULT_OK, resultIntent);
finish();
}
});
}
}
activity_2.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:gravity="center"
android:orientation="vertical"
android:padding="16dp"
tools:context="tech.codingpoint.startactivityforresultexample.Activity2">
<TextView
android:id="@+id/text_view_numbers"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Numbers: "
android:textSize="30sp" />
<Button
android:id="@+id/button_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="add" />
<Button
android:id="@+id/button_subtract"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="subtract" />
</LinearLayout>
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:gravity="center"
android:orientation="vertical"
android:padding="16dp"
tools:context="tech.codingpoint.startactivityforresultexample.MainActivity">
<EditText
android:id="@+id/edit_text_number1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Number 1"
android:inputType="number" />
<EditText
android:id="@+id/edit_text_number2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Number 2"
android:inputType="number" />
<TextView
android:id="@+id/text_view_result"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Result"
android:textSize="30sp" />
<Button
android:id="@+id/button_open_activity2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="open activity 2" />
</LinearLayout>
MainActivity.java
package tech.codingpoint.startactivityforresultexample;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private TextView mTextViewResult;
private EditText mEditTextNumber1;
private EditText mEditTextNumber2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTextViewResult = findViewById(R.id.text_view_result);
mEditTextNumber1 = findViewById(R.id.edit_text_number1);
mEditTextNumber2 = findViewById(R.id.edit_text_number2);
Button buttonOpenActivity2 = findViewById(R.id.button_open_activity2);
buttonOpenActivity2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mEditTextNumber1.getText().toString().equals("")
|| mEditTextNumber2.getText().toString().equals("")) {
Toast.makeText(MainActivity.this, "Please insert numbers", Toast.LENGTH_SHORT).show();
} else {
int number1 = Integer.parseInt(mEditTextNumber1.getText().toString());
int number2 = Integer.parseInt(mEditTextNumber2.getText().toString());
Intent intent = new Intent(MainActivity.this, Activity2.class);
intent.putExtra("number1", number1);
intent.putExtra("number2", number2);
startActivityForResult(intent, 1);
}
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 1) {
if (resultCode == RESULT_OK) {
int result = data.getIntExtra("result", 0);
mTextViewResult.setText("" + result);
}
if (resultCode == RESULT_CANCELED) {
mTextViewResult.setText("Nothing selected");
}
}
}
}