Aplikacja nie działa po wstawieniu map Android.

Witajcie. Mam problem, nad którym siedzę już sporo czasu. Mianowicie mam trzy activity i jedno okno z mapą. Przed wstawieniem mapy apka działa, a po wstawieniu jej zaraz przy włączeniu apka przestaje działać. Kompletnie nie mam pojęcia co tu nie gra. Daję tutaj kod wszystkich activities. (nie wstawiam ostatniego activity, bo jest jeszcze puste)

MainActivity:

package com.example.luq92.mp;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends ActionBarActivity {
//przelaczanie nowego activity

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);

        Button zaloguj = (Button) findViewById(R.id.zaloguj);



        //Listening to button event
        zaloguj.setOnClickListener(new View.OnClickListener() {

            public void onClick(View arg0) {
                //Starting a new Intent
                Intent nextScreen = new Intent(getApplicationContext(), MapsActivity.class);




                startActivity(nextScreen);

            }
        });
    }
}
 

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity"
    android:background="#ff000000">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/zaloguj"
        android:id="@+id/zaloguj"
        android:layout_alignParentBottom="true"
        android:layout_alignParentEnd="true" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/Login"
        android:layout_alignParentTop="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="99dp"
        android:background="#ffffffff"
        android:layout_alignParentEnd="true"
        android:autoText="true"
        android:text="@string/login" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPassword"
        android:ems="10"
        android:id="@+id/Haslo"
        android:layout_centerVertical="true"
        android:layout_toStartOf="@+id/zaloguj"
        android:layout_alignParentStart="true"
        android:layout_alignEnd="@+id/Login"
        android:background="#ffffffff"
        android:text="@string/haslo" />
</RelativeLayout>
 

MapsActivity

package com.example.luq92.mp;

import android.support.v4.app.FragmentActivity;
import android.os.Bundle;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

public class MapsActivity extends FragmentActivity {

    private GoogleMap mMap; // Might be null if Google Play services APK is not available.

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

    @Override
    protected void onResume() {
        super.onResume();
        setUpMapIfNeeded();
    }

    
    private void setUpMapIfNeeded() {
        // Do a null check to confirm that we have not already instantiated the map.
        if (mMap == null) {
            // Try to obtain the map from the SupportMapFragment.
            mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                    .getMap();
            // Check if we were successful in obtaining the map.
            if (mMap != null) {
                setUpMap();
            }
        }
    }

    
    private void setUpMap() {
        mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
    }
} 

google_maps_api.xml

<resources>
  
    <string name="google_maps_key" translatable="false" templateMergeStrategy="preserve">
        AIzaSyBuALWUMRq351fkM0tKdHqY3lCqDw96-Do
    </string>
</resources> 

MainActivity3:

 package com.example.luq92.mp;

import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;


public class MainActivity3 extends Activity {


    @Override

    //powracanie do mapy przez guzik anuluj
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_activity3);

        Button next = (Button) findViewById(R.id.anuluj);
        next.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                Intent myIntent = new Intent(view.getContext(), MapsActivity.class);
                startActivityForResult(myIntent, 0);
            }
        });
    }
}

activity_main3.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context="com.example.luq92.mp.MainActivity3">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/dodaj_znacznik"
        android:id="@+id/dodaj_znacznik"
        android:layout_alignParentBottom="true"
        android:layout_alignParentStart="true" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/anuluj"
        android:id="@+id/anuluj"
        android:layout_alignTop="@+id/dodaj_znacznik"
        android:layout_alignParentEnd="true" />

</RelativeLayout>