Sometimes, you have to call a method of a fragment from its parent activity. For example, you have a fragment that displays a list of SMS. When there is a new incoming SMS, the SMS receiver in your activity will call a method of the fragment to upload the SMS list. Calling the method of the fragment from its parent activity is simple. You need to find the fragment by its tag name using the findFragmentByTagName of FragmentManager class. Then call the method of the fragment to do something that you wish.
In the example application below, when a new message arrives, the broadcast receiver (SMSReceiver) defined and registered in the MainActivity will call the showLastSMS() method of the LastSMSFragment to display the last sms.



<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

   android:layout_width="match_parent"

   android:layout_height="match_parent"

   android:orientation="vertical"

  >

   <TextView

      android:id="@+id/txtlastsms"

      android:layout_width="match_parent"

      android:layout_height="match_parent"

      android:padding="10dp"

      android:singleLine="false"



      />



</LinearLayout>

import android.os.Bundle;

import android.support.v4.app.Fragment;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.TextView;

public class LastSMSFragment extends Fragment {

  private TextView tv;

   public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

      //Inflate the layout for this fragment

      View view = inflater.inflate(R.layout.fragmentlayout, container, false);      

      tv=(TextView)view.findViewById(R.id.txtlastsms);

      return view;

   }

   public static LastSMSFragment newInstance() {

      return (new LastSMSFragment());

   }

   public void showLastSMS(String mess){

      tv.setText(mess);

   }

}

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.content.IntentFilter;

import android.os.Bundle;

import android.support.v4.app.FragmentTransaction;

import android.support.v7.app.ActionBarActivity;

import android.telephony.SmsManager;

import android.telephony.SmsMessage;

import android.view.View;

import android.widget.Toast;



public class MainActivity extends ActionBarActivity {



   private SMSReceiver smsReceiver;

   protected void onCreate(Bundle savedInstanceState) {

      super.onCreate(savedInstanceState);

      setContentView(R.layout.activity_main);

      smsReceiver = new SMSReceiver();

      // Register receiver to receive the last sms

      IntentFilter intentFilter = new IntentFilter("android.provider.Telephony.SMS_RECEIVED");

      intentFilter.setPriority(999);

      registerReceiver(smsReceiver, intentFilter);

      // Display fragment

      showFragment();

      // Sending sms for testing

      sendSms("089256724", "This is the last sms.");

   }



   private class SMSReceiver extends BroadcastReceiver {

      @Override

      public void onReceive(Context context, Intent intent) {



        Bundle bundle = intent.getExtras();

        SmsMessage[] smsm = null;

        String sms_str = "";

        if (bundle != null) {

           // Get the SMS message

           Object[] pdus = (Object[]) bundle.get("pdus");

           smsm = new SmsMessage[pdus.length];

           for (int i = 0; i < smsm.length; i++) {

              smsm[i] = SmsMessage.createFromPdu((byte[]) pdus[i]);

              sms_str += "Sent From: " + smsm[i].getOriginatingAddress();

              sms_str += "\r\nMessage: ";

              String message=smsm[i].getMessageBody().toString();

              sms_str +=smsm[i].getMessageBody().toString();

              sms_str += "\r\n";



           }

           LastSMSFragment lastSMSFragment = (LastSMSFragment)getSupportFragmentManager().findFragmentByTag("lastSMSFragment");

           if(lastSMSFragment==null) // if the fragment  is not showing, show it

              showFragment();

           // Call fragment method to display sms in the textview

           lastSMSFragment.showLastSMS(sms_str);



        }



      }

   }



   public void showFragment(){

      LastSMSFragment lastSMSFragment=LastSMSFragment.newInstance();

      FragmentTransaction transact=getSupportFragmentManager().beginTransaction();

      transact.add(R.id.fragment_container, lastSMSFragment, "lastSMSFragment");

      transact.commit();

   }



   public void sendSms(String phoneNo, String sms){

      SmsManager smsMgt= SmsManager.getDefault();

      smsMgt.sendTextMessage(phoneNo, null, sms, null, null);

      Toast.makeText(this,"The message was sent.", Toast.LENGTH_SHORT).show();



   }



   public void onPause(){

      super.onPause();

      try {

        // Unregister the receiver

        unregisterReceiver(this.smsReceiver);

      }catch(Exception e){}

   }

}

<uses-permission android:name= "android.permission.SEND_SMS" />

<uses-permission android:name= "android.permission.RECEIVE_SMS" />

Posted by: Dara | post date: 03-28-2015 | Subject: Android Apps Development