A minimalistic guide to Facebook loginsignup implementation

<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" />

<com.facebook.login.widget.LoginButton
    android:id="@+id/login_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
    @Override
    public void onSuccess(LoginResult loginResult) {
        // Completed without error. You might want to use the retrieved data here.
    }

    @Override
    public void onCancel() {
        // The user either cancelled the Facebook login process or didn't authorize the app.
    }

    @Override
    public void onError(FacebookException exception) {
        // The dialog was closed with an error. The exception will help you recognize what exactly went wrong.
    }
});