In This Tutorial we show the basic example of  sending SMS using SmsManager API.
First We make a layout.
Android layout file have a two  EditText (phone no, sms message) and  button to send the SMS message.
File : res/layout/main.xml
 
  <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/linearLayout1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#C2B280"
    android:orientation="vertical" >
    <TextView
        android:id="@+id/textViewPhoneNo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Enter Phone Number : "
        android:textAppearance="?android:attr/textAppearanceLarge" />
    <EditText
        android:id="@+id/editTextPhoneNo"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:phoneNumber="true" >
    </EditText>
    <TextView
        android:id="@+id/textViewSMS"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Message : "
        android:textAppearance="?android:attr/textAppearanceLarge" />
    <EditText
        android:id="@+id/editTextSMS"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:inputType="textMultiLine"
        android:lines="5"
        android:gravity="top" />
    <Button
        android:id="@+id/buttonSend"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Send" /></LinearLayout> 
 
 
File : SMSActivity.java – Activity to send SMS
package com.bishnu.android;
import android.app.Activity;
import android.os.Bundle;
import android.telephony.SmsManager;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class SMSActivity extends Activity {
 Button buttonSend;
 EditText textPhoneNo;
 EditText textSMS;
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  buttonSend = (Button) findViewById(R.id.buttonSend);
  textPhoneNo = (EditText) findViewById(R.id.editTextPhoneNo);
  textSMS = (EditText) findViewById(R.id.editTextSMS);
  buttonSend.setOnClickListener(new OnClickListener() {
   @Override
   public void onClick(View v) {
    String phoneNo = textPhoneNo.getText().toString();
    String sms = textSMS.getText().toString();
    try {
     SmsManager smsManager = SmsManager.getDefault();
     smsManager.sendTextMessage(phoneNo, null, sms, null, null);
     Toast.makeText(getApplicationContext(), "SMS Sent!",
       Toast.LENGTH_LONG).show();
    } catch (Exception e) {
     Toast.makeText(getApplicationContext(),
       "SMS faild, please try again later!",
       Toast.LENGTH_LONG).show();
     e.printStackTrace();
    }
   }
  });
 }
}
 
 
     Need SEND_SMS permission in AndroidManifest.xml
<uses-permission android:name="android.permission.SEND_SMS" />
 
 
    File : AndroidManifest.xml 
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.bishnu.android"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-sdk android:minSdkVersion="10" />
    <uses-permission android:name="android.permission.SEND_SMS" />
    <application
        android:debuggable="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:label="@string/app_name"
            android:name=".SMSActivity" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>
 
 
  Open  Two Emulator for testing SMS.
  Phone Number- 5558(Another Emulator Number).
 Download Sample Code from this 
link
 Click This link then open new Tab and after click on Left-Top File option and click on Download.