Passing Data Using An Intent Object In Android Applications

Overview

In my previous article Return Data Using Intent Object in Android Applications, I discussed how to return the data using the intent object between two activities. If you are new to app creation in Android, refer to the following articles:

1. Android Programming - Day One 

2. Android Programming - Day Two 

3. How To Display a Dialog Window in Android

4. How To Display a Progress Dialog Window in Android 

5. Intent in Android  

Introduction

In this article, I will explain about passing the data between two or more activities, using the Intent object in Android applications.

Coding

I made some changes in the design of the existing file, activity_my_second.xml.

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical">
  <TextView android:text="@string/MySecond_Activity"
      android:layout_width="fill_parent"
      android:layout_marginTop="20dp"
      android:layout_height="wrap_content" />
  <Button android:layout_height="wrap_content"
      android:layout_width="fill_parent"
      android:text="Return to Main Activity"
      android:id="@+id/btnOk"
      android:onClick="onClick" />
</LinearLayout>

In MySecondActivity.java class, add a method onClick() and get the data passed from the main activity, using getIntent() and getStringExtra().

package com.example.administrator.intentexampleapp;

 import android.content.Intent;
 import android.net.Uri;
 import android.support.v7.app.ActionBarActivity;
 import android.os.Bundle;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 import android.widget.EditText;
 import android.widget.Toast;

 public class MySecondActivity extends ActionBarActivity {

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_my_second);
         // Here we get the data passed in using getStringExtra() method.
         Toast.makeText(this,getIntent().getStringExtra("string1"),Toast.LENGTH_SHORT).show();

         // Here we the data passed in using getIntExtra() method.
         Toast.makeText(this,Integer.toString(getIntent().getIntExtra("Marks1",80)),Toast.LENGTH_SHORT).show();

         // Get the Bundle object
         Bundle bundle=getIntent().getExtras();

         // Here we get the data using the getString() method.
         Toast.makeText(this, bundle.getString("string2"),Toast.LENGTH_SHORT).show();

         // Here we get the data using the geInt() method.
         Toast.makeText(this,Integer.toString(bundle.getInt("Marks2")), Toast.LENGTH_SHORT).show();
     }

     public void onClick(View view)
     {
         //create an instance of Intent object to return data.
         Intent data= new Intent();
         // Here we use the putExtra() method to return some value
         data.putExtra("Marks3",70);
         // Here we use the setData() method to return some value
         data.setData(Uri.parse("Data passed to the Main Activity"));
         // Here we use result with OK
         setResult(RESULT_OK,data);
         //Destroy the current activity
         finish();
     }
 }

Add one button in the activity_main.xml file.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:orientation="vertical">
     <Button
         android:layout_width="fill_parent"
         android:layout_height="50dp"
         android:text="Show second activity"
         android:layout_marginTop="20dp"
         android:onClick="showSecondActivity" />
 </LinearLayout>

In the MainActivity.java class, implement the showSecondActivity() method.

package com.example.administrator.intentexampleapp;

 import android.support.v7.app.ActionBarActivity;
 import android.os.Bundle;
 import android.view.View;
 import android.content.Intent;
 import android.widget.Toast;

 public class MainActivity extends ActionBarActivity {
     int request_Value=1;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
     }
     public void showSecondActivity(View view)
     {
         //Created an instance of second activity using Intent.
         Intent intent= new Intent("android.intent.action.MySecondActivity");

         //Here we use putExtra() to add new name/value pairs.
         intent.putExtra("string1","This is first string");
         intent.putExtra("Marks1",80);

         //Here we use a Bundle object to add new name and values pairs
         Bundle bundle = new Bundle();
         bundle.putString("string2", "This is second string");
         bundle.putInt("Marks2", 60);

         // Attach the Bundle object to the Intent object
         intent.putExtras(bundle);

         startActivityForResult(intent, request_Value);
     }

     public void onActivityResult(int requestCode, int resultCode, Intent data){
         if(requestCode == request_Value){
             //if the result is OK
             if(resultCode == RESULT_OK){

                 // Here we get the result using getIntExtra() method
                 Toast.makeText(this,Integer.toString(data.getIntExtra("Marks3",0)),Toast.LENGTH_SHORT).show();

                 //Here we get the result using getData() method.
                 Toast.makeText(this,data.getData().toString(),Toast.LENGTH_SHORT).show();
             }
         }
     }
 }

Execute the application. It will show the following output:



Click on Show Second Activity button. Now, the data is passed to the second activity.



Click on RETURN TO MAIN ACTIVITY button. Data from the second activity is passed to the main activity.



Explanation In this app, we use the putExtra() method of an Intent object to add a name/value pair.

//Here we use putExtra() to add new name/value pairs.
 intent.putExtra("string1","This is first string");
 intent.putExtra("Marks1",80);

Above statements add two name/value pairs to the Intent object. First one is of type string and the second one is of type integer. Apart from this, create a Bundle object and attach it using the putExtras method(). Bundle object is just like a dictionary object. It contains a set of name/ value pairs. So, the following statements create a Bundle object, and then add two name/value pairs to it.

//Here we use a Bundle object to add new name and values pairs
 Bundle bundle = new Bundle();
 bundle.putString("string2", "This is second string");
 bundle.putInt("Marks2", 60);
// Attach the Bundle object to the Intent object
 intent.putExtras(bundle);

Call the second activity.

startActivityForResult(intent, request_Value);

On the second activity, we first obtain the Intent object, using the getIntent() method. Then, call its getStringExtras() method to get the string value set, using the putExtra() method.

// Here we get the data passed in using getStringExtra() method.
 Toast.makeText(this,getIntent().getStringExtra("string1"),Toast.LENGTH_SHORT).show();

Now, we have to call method to extract the name/value pair, based on the type of data set. Use the getIntExtra() method for the integer value.

// Here we the data passed in using getIntExtra() method.
Toast.makeText(this,Integer.toString(getIntent().getIntExtra("Marks1",80)),Toast.LENGTH_SHORT).show();

Retrieve the Bindle object by using getExtras() method.

// Get the Bundle object
 Bundle bundle=getIntent().getExtras();

Get the individual name/value pairs by using getString() method.

// Here we get the data using the getString() method.
 Toast.makeText(this, bundle.getString("string2"),Toast.LENGTH_SHORT).show();

Get the integer value by using getInt() method.

// Here we get the data using the geInt() method.
 Toast.makeText(this,Integer.toString(bundle.getInt("Marks2")), Toast.LENGTH_SHORT).show();

From the second activity, pass the data to the Main activity by using setData() method, as I have already discussed in my previous article.

//create an instance of Intent object to return data.
 Intent data= new Intent();
 // Here we use the putExtra() method to return some value
 data.putExtra("Marks3",70);
 // Here we use the setData() method to return some value
 data.setData(Uri.parse("Data passed to the Main Activity"));
 // Here we use result with OK
 setResult(RESULT_OK,data);
 //Destroy the current activity
 finish();

To retrieve the data set, using the setData() method, use the getData() method,

// Here we get the result using getIntExtra() method
 Toast.makeText(this,Integer.toString(data.getIntExtra("Marks3",0)),Toast.LENGTH_SHORT).show();

 //Here we get the result using getData() method.
 Toast.makeText(this,data.getData().toString(),Toast.LENGTH_SHORT).show();

Conclusion

In this article, we saw how to pass data from one activity to the second activity and vice versa. In the next article, I will explain about Fragment.