package com.milcanx.fragmentlerarasiveri;

import android.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class FragmentBOSS extends AppCompatActivity implements Communicator {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fragment_boss);

    }

    @Override
    public void respond(String data) {

            FragmentManager manager = getFragmentManager();
            FragmentB fmB = (FragmentB) manager.findFragmentById(R.id.fragmentBinLayout);
            fmB.ChangeText(data);


    }
}

Burada   FragmentB fmB = (FragmentB) manager.findFragmentById(R.id.fragmentBinLayout); işleminde hata alıyorum

Hata şu 

06-17 08:52:18.044 10128-10128/com.milcanx.test E/AndroidRuntime: FATAL EXCEPTION: main
                                                                  Process: com.milcanx.test, PID: 10128
                                                                  java.lang.ClassCastException: com.milcanx.fragmentlerarasiveri.FragmentA cannot be cast to com.milcanx.fragmentlerarasiveri.FragmentB
                                                                      at com.milcanx.fragmentlerarasiveri.FragmentBOSS.respond(FragmentBOSS.java:20)
                                                                      at com.milcanx.fragmentlerarasiveri.FragmentA.onClick(FragmentA.java:32)
                                                                      at android.view.View.performClick(View.java:4438)
                                                                      at android.view.View$PerformClick.run(View.java:18422)
                                                                      at android.os.Handler.handleCallback(Handler.java:733)
                                                                      at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                      at android.os.Looper.loop(Looper.java:136)
                                                                      at android.app.ActivityThread.main(ActivityThread.java:5001)
                                                                      at java.lang.reflect.Method.invokeNative(Native Method)
                                                                      at java.lang.reflect.Method.invoke(Method.java:515)
                                                                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
                                                                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
                                                                      at dalvik.system.NativeStart.main(Native Method)

izlemiş olduğum bir derste anlatılanı yazdım 
ancak her isime tüm numaraların 2 katı kadar rehbere kişi ekleyip gösteriyor 
yani 100 kişi varsa a ismini 200 sefer gösteriyor. 
Bu sorunun ikinci while dan kaynaklandığını düşünüyorum 
ancak konuda yetersiz olduğumdan çözemedim. Bakabilir misiniz.




package com.milcanx.cont_provider;

import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.provider.ContactsContract;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class Content_Provider_Act extends AppCompatActivity {

    final List<Kisi> kisiler = new ArrayList<Kisi>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_content__provider_act);

        final ListView list = (ListView) findViewById(R.id.lvList);
        OzelAdapter adapter = new OzelAdapter(this, kisiler);
        list.setAdapter(adapter);

        final Uri content_uri = ContactsContract.Contacts.CONTENT_URI;
        final String ID = ContactsContract.Contacts._ID;
        final String Isim = ContactsContract.Contacts.DISPLAY_NAME;
        final String Tel_Durumu = ContactsContract.Contacts.HAS_PHONE_NUMBER;

        final Uri Phone_uri = ContactsContract.CommonDataKinds.Phone.CONTENT_URI;
        final String Phone_ID = ContactsContract.CommonDataKinds.Phone.CONTACT_ID;
        final String Phone_Number = ContactsContract.CommonDataKinds.Phone.NUMBER;

        ContentResolver contentresolver = getContentResolver();
        Cursor cursor = contentresolver.query(content_uri, null, null, null, null);

        assert cursor != null;
        while (cursor.moveToNext()) {
            String kisi_id = cursor.getString(cursor.getColumnIndex(ID));
            String kisi_isim = cursor.getString(cursor.getColumnIndex(Isim));
            String tel_durum = cursor.getString(cursor.getColumnIndex(Tel_Durumu));

            Bitmap photo = null;
            try {
                InputStream inputstream = ContactsContract.Contacts.openContactPhotoInputStream(getContentResolver(), ContentUris.withAppendedId(content_uri, Long.valueOf(kisi_id)));
                if (inputstream != null) photo = BitmapFactory.decodeStream(inputstream);
                if (inputstream != null) {
                    inputstream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }

            if (tel_durum.equals("1")) {
                Cursor phonecursor = contentresolver.query(Phone_uri, null, Phone_ID + " -?", new String[]{kisi_id}, null);
                assert phonecursor != null;
                while (phonecursor.moveToNext()) {
                    final String t = phonecursor.getString(phonecursor.getColumnIndex(Phone_Number));
                    Kisi k = new Kisi(kisi_isim, t);
                    k.photo = photo;
                    kisiler.add(k);
                    list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                        @Override
                        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                            Intent i = new Intent(Intent.ACTION_DIAL, Uri.parse("tel:" + kisiler.get(position).getTel_no()));
                            startActivity(i);
                        }
                    });

                }
                phonecursor.close();
            }

        }


    }
}

Material Design UI Android Template App , almış olduğum uygulamadır.

İçerisinde bulunan bu modülleri tek tek nasıl kullanabilirim. İlk açıldığında yani run denildiğinde NotBoringAction çalışıyor. Seçim yapamıyorum