SharedPrefenceres Uygulama Çökmesi

package deneme.myapplication;

import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Color;
import android.preference.PreferenceManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.RelativeLayout;

public class MainActivity extends AppCompatActivity implements SharedPreferences.OnSharedPreferenceChangeListener {
int sayma;
Button buton;
    SharedPreferences hafiza, ayarhafizasi;
    RelativeLayout anasayfa_arkaplan;
    Boolean sesdurumu, titresimdurumu;

    @Override
    protected void onPause() {
        SharedPreferences.Editor editor= hafiza.edit();
        editor.putInt("sayma_anahtarı", sayma);
        editor.commit();
        super.onPause();
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
         buton= (Button) findViewById(R.id.button);
         hafiza= PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
         ayarhafizasi= PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        ayaryukle();
        anasayfa_arkaplan= (RelativeLayout) findViewById(R.id.anasayfa_arkaplan);
        sayma=hafiza.getInt("sayma_anahtarı", 0);
         buton.setText(""+sayma);
         buton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                sayma++;
                buton.setText(""+sayma);
            }
        });
    }

    private void ayaryukle() {
        String pozisyon=ayarhafizasi.getString("renk","3");
        switch (Integer.valueOf(pozisyon)){
            case 0: anasayfa_arkaplan.setBackgroundColor(Color.RED);
                break;
            case 1: anasayfa_arkaplan.setBackgroundColor(Color.GREEN);
                break;
            case 2: anasayfa_arkaplan.setBackgroundColor(Color.BLUE);
                break;
            case 3: anasayfa_arkaplan.setBackgroundColor(Color.DKGRAY);
                break;
            case 4: anasayfa_arkaplan.setBackgroundColor(Color.LTGRAY);
                break;

        }
        sesdurumu=ayarhafizasi.getBoolean("ses", false);
        titresimdurumu=ayarhafizasi.getBoolean("titresim", false);
        ayarhafizasi.registerOnSharedPreferenceChangeListener(MainActivity.this);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu){
        getMenuInflater().inflate(R.menu.menu_main,menu);
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item){
        int id=item.getItemId();
        if (id==R.id.sifirla){
            sayma=0;
buton.setText(""+sayma);
            return true;
        }
        if (id==R.id.ayarlar){
            Intent ıntent=new Intent(getApplicationContext(), ayarlar.class);
            startActivity(ıntent);
            return true;
        }

        return  super.onOptionsItemSelected(item);
    }

    @Override
    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String s) {
        ayaryukle();
    }
}