Login facebook opening alone in android application

I'm creating an android application that signs in with facebook. This is already working, but something is happening that I can not solve.

According to the examples of the facebook documentation itself, the code that makes the calls to facebook api is inside the onCreate() method, and this causes me to open the login page (which has the login button with facebook) it already automatically opens facebook to ask for the permissions even without I have clicked the login button with facebook.

What do I do so that it will only open the login screen when I click the "Log in with Facebook" button?

Here are the codes:

LoginActivity.java

public class LoginActivity extends Activity {

CallbackManager callbackManager;
LoginButton loginButton;
LoginManager loginManager;

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

    Log.d("Teste", "onCreate inicio");

    FacebookSdk.sdkInitialize(getApplicationContext());
    callbackManager = CallbackManager.Factory.create();

    loginManager.getInstance().logInWithReadPermissions(this, Arrays.asList("public_profile", "user_friends"));
    LoginManager.getInstance().registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
        @Override
        public void onSuccess(LoginResult loginResult) {
            // App code
            Log.d("Teste", "onSuccess inicio [Token = " + loginResult.getAccessToken() + "], [Permissões = " + loginResult.getRecentlyGrantedPermissions() +
                    "], [Negações = " + loginResult.getRecentlyDeniedPermissions() + "] Json: "+ loginResult.toString());
        }

        @Override
        public void onCancel() {
            // App code
            Log.d("Teste", "onCancel inicio");
        }

        @Override
        public void onError(FacebookException exception) {
            // App code
            Log.d("Teste", "onError( " + exception.toString() + ")");
        }
    });


}

activity_login.xml

<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#F76B03"
android:scrollbars="none"
android:gravity="center">

<com.facebook.login.widget.LoginButton
    android:id="@+id/login_button"
    android:layout_width="match_parent"
    android:layout_height="35dp"
    android:layout_gravity="center_horizontal"
    android:layout_marginLeft="25dp"
    android:layout_marginRight="25dp"/>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginBottom="10dp"
    android:layout_marginTop="5dp"
    android:layout_gravity="center_horizontal"
    android:text="ou"
    android:textColor="#000000" />


<EditText style="@style/tvFullParent"
    android:id="@+id/etLogin"
    android:background="@drawable/shapeedittext"
    android:inputType="textEmailAddress"
    android:drawableLeft="@drawable/ic_action_user"
    android:hint="E-mail"/>

<EditText style="@style/tvFullParent"
    android:id="@+id/etPassword"
    android:background="@drawable/shapeedittext"
    android:inputType="textPassword"
    android:drawableLeft="@drawable/ic_action_lock_closed"
    android:hint="Senha"/>

<Button
    android:id="@+id/btnLogin"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginLeft="22dp"
    android:layout_marginRight="22dp"
    android:text="@string/btnLogin"/>

androidmanifest.xml

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

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >

    <meta-data
        android:name="com.facebook.sdk.ApplicationId"
        android:value="@string/facebook_app_id" />

    <activity
        android:name=".SplashActivity"
        android:label="@string/app_name"
        android:screenOrientation="portrait">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".LoginActivity"
        android:label="@string/title_activity_login"
        android:screenOrientation="portrait">
    </activity>
    <activity android:name="com.facebook.FacebookActivity"
        android:configChanges=
            "keyboard|keyboardHidden|screenLayout|screenSize|orientation"
        android:theme="@android:style/Theme.Translucent.NoTitleBar"
        android:label="@string/app_name" />
    </application>