How to exchange data between Activities in Android – Intent putExtra method

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Today’s post is on how to exchange data between activities using Android Intent putExtra and getExtras methods called in an activity code. We are going to show you how to send objects of your own type and read them in an activity. Our example is based on the Android read SMS tutorial. We have modified this application to show SMS contents in a new view. This is the result.

Android Intent putExtra – SMS Inbox list

Android Intent putExtra – SMS Details

Take a look at the code modifications.

SMSData.java

package com.itcuties.android.apps.data;

import java.io.Serializable;

/**
* This class represents SMS.
*
* @author itcuties
*
*/
public class SMSData implements Serializable {

   private static final long serialVersionUID = 3185099950959560099L;
   
   // Number from witch the sms was send
   private String number;
   // SMS text body
   private String body;
   
   public String getNumber() {
       return number;
   }
   
   public void setNumber(String number) {
       this.number = number;
   }
   
   public String getBody() {
       return body;
   }
   
   public void setBody(String body) {
       this.body = body;
   }
   
}

We made SMSData class implement Serializable interface which means that it needs to have a serialVersionUID class attribute. For more info on Java Serialization see our tutorial.

private static final long serialVersionUID = 3185099950959560099L;

This class objects are now ready to be sent between activities.

activity_sms.xml

This is the view where SMS data is being displayed. There are two TextView elements here. One for displaying SMS sender number, the second one is for displaying SMS body.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
       android:layout_width="fill_parent"
       android:layout_height="fill_parent" >

       <TextView
           android:id="@+id/smsDetailsNumberText"
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:layout_alignParentTop="true"
           android:layout_centerHorizontal="true"
           android:layout_marginTop="71dp"
           android:textColor="#ff0000"
           android:text="NUMBER_GOES_HERE" />

       <TextView
           android:id="@+id/smsDetailsBodyText"
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:layout_alignLeft="@+id/smsDetailsNumberText"
           android:layout_centerVertical="true"
           android:textColor="#00ff00"
           android:text="BODY GOES HERE" />


</RelativeLayout>

MainActivity.java

This code displays the contents of SMS Inbox in a form of the list using ListView. This code is explained in details in our previous tutorial – Android read SMS. Our modification for this tutorial was made in the onListItemClick method.

package com.itcuties.android.apps;

import java.util.ArrayList;
import java.util.List;

import android.app.ListActivity;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.ListView;

import com.itcuties.android.apps.data.SMSData;

/**
* Main Activity. Displays a list of numbers.
*
* @author itcuties
*
*/
public class MainActivity extends ListActivity {

   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);

       List<SMSData> smsList = new ArrayList<SMSData>();
       
       Uri uri = Uri.parse("content://sms/inbox");
       Cursor c= getContentResolver().query(uri, null, null ,null,null);
       startManagingCursor(c);
       
       // Read the sms data and store it in the list
       if(c.moveToFirst()) {
           for(int i=0; i < c.getCount(); i++) {
               SMSData sms = new SMSData();
               sms.setBody(c.getString(c.getColumnIndexOrThrow("body")).toString());
               sms.setNumber(c.getString(c.getColumnIndexOrThrow("address")).toString());
               smsList.add(sms);
               
               c.moveToNext();
           }
       }
       
       // Set smsList in the ListAdapter
       setListAdapter(new ListAdapter(this, smsList));
       
   }

   @Override
   protected void onListItemClick(ListView l, View v, int position, long id) {
       // Get sms data from the list
       SMSData sms = (SMSData)getListAdapter().getItem(position);
       
       // Create an intent
       Intent intent = new Intent(this, SMSActivity.class);
       intent.putExtra("sms", sms);
       
       // Start sms details activity
       startActivity(intent);
       
   }
   
}

Sending objects between activities – Android putExtra method

This is the code that puts SMSData object in an intent using putExtra method and starts a new activity. SMSData object is available for the new SMSActivity activity that was just started.

// Create an intent
Intent intent = new Intent(this, ActivityClass.class);
intent.putExtra("key", yourObjectInstance);

// Start activity
startActivity(intent);

SMSActivity.java

In this activity SMSData object contents is being displayed. We are reading data using getIntent().getExtras().get() method calls.

package com.itcuties.android.apps;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

import com.itcuties.android.apps.data.SMSData;

public class SMSActivity extends Activity {

   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       
       setContentView(R.layout.activity_sms);
       
       TextView smsSenderNumber = (TextView)findViewById(R.id.smsDetailsNumberText);
       TextView smsBody           = (TextView)findViewById(R.id.smsDetailsBodyText);
   
       // Get sms data
       SMSData sms = (SMSData)getIntent().getExtras().get("sms");
       
       // Display sms data
       smsSenderNumber.setText(sms.getNumber());
       smsBody.setText(sms.getBody());
       
   }
}

Reading object in an activity – Android getExtras() method

To read data that was send to the activity using putExtra method use this code.

YourType yourObjectInstance = (YourType)getIntent().getExtras().get("key");

Download this sample code here.

This code is available on our GitHub repository as well.