LoginActivity.java

package com.betaseries.betaseries.ui.login;

import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.betaseries.betaseries.R;
import com.betaseries.betaseries.ui.AbstractActivity;
import com.betaseries.betaseries.ui.MainActivity;
import com.github.ksoichiro.android.observablescrollview.CacheFragmentStatePagerAdapter;
import com.viewpagerindicator.PageIndicator;

import butterknife.Bind;
import butterknife.ButterKnife;
import butterknife.OnClick;

/**
 * Created by florentchampigny on 24/08/15.
 */
public class LoginActivity extends AbstractActivity {

    public static final boolean FORCE_LOGIN = false;

    @Bind(R.id.viewPager)
    ViewPager viewPager;

    @Bind(R.id.indicator)
    PageIndicator pageIndicator;

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

    @Override
    protected void onPostCreate(@Nullable Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);

        if (FORCE_LOGIN || !userManager.hasUser()) {
            displayViewPager();
        } else {
            startActivity(new Intent(this, MainActivity.class));
            finish();
            overridePendingTransition(0, 0);
        }

    }

    protected void displayViewPager() {
        viewPager.setAdapter(new CacheFragmentStatePagerAdapter(getSupportFragmentManager()) {
            @Override
            protected Fragment createItem(int position) {
                switch (position) {
                    case 0:
                        return new Fragment() {
                            public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
                                return inflater.inflate(R.layout.fragment_login_1, container, false);
                            }
                        };
                    case 1:
                        return new Fragment() {
                            public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
                                return inflater.inflate(R.layout.fragment_login_2, container, false);
                            }
                        };
                    case 2:
                        return LoginFragment.newInstance();
                }
                return null;
            }

            @Override
            public int getCount() {
                return 3;
            }
        });

        pageIndicator.setViewPager(viewPager);
    }

    @OnClick(R.id.skip)
    public void onClickPrev() {
        if (viewPager.getCurrentItem() < viewPager.getAdapter().getCount())
            viewPager.setCurrentItem(viewPager.getAdapter().getCount() - 1, true);
    }

    @OnClick(R.id.next)
    public void onClickNext() {
        if (viewPager.getCurrentItem() < viewPager.getAdapter().getCount())
            viewPager.setCurrentItem(viewPager.getCurrentItem() + 1, true);
    }
}