MainActivity.java

package com.tfltravelalerts;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.AccessibilityDelegateCompat;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewCompat;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.View;
import android.view.accessibility.AccessibilityEvent;

import com.actionbarsherlock.view.MenuItem;
import com.google.analytics.tracking.android.EasyTracker;
import com.tfltravelalerts.alerts.ViewAlertsFragment;
import com.tfltravelalerts.common.TflBaseActivity;
import com.tfltravelalerts.debug.ExceptionViewerActivity;
import com.tfltravelalerts.navigationdrawer.AppScreen;
import com.tfltravelalerts.navigationdrawer.AppScreen.Screen;
import com.tfltravelalerts.navigationdrawer.AppScreenUtil;
import com.tfltravelalerts.statusviewer.LineStatusViewerListFragment;
import com.tfltravelalerts.weekend.WeekendStatusViewerListFragment;
import com.viewpagerindicator.PageIndicator;

import org.holoeverywhere.app.Fragment;

public class MainActivity extends TflBaseActivity {

    private ViewPager mViewPager;
    private View mViewPagerIndicator;
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        analyticsCallback();
        setContentView(R.layout.main_activity);
        mViewPager = (ViewPager) findViewById(R.id.view_pager);
        mViewPagerIndicator = findViewById(R.id.view_pager_indicator);
        setupViewPager();
        initViewPager(savedInstanceState);
        ((PageIndicator) mViewPagerIndicator).setViewPager(mViewPager);

        getSupportActionBar().setHomeButtonEnabled(true);
    }

    private void analyticsCallback() {
        Uri uri = getIntent().getData();
        // Call setContext() here so that we can access EasyTracker
        // to update campaign information before activityStart() is called.
        EasyTracker.getInstance().setContext(this);

        if (uri != null) {
            if(uri.getQueryParameter("utm_source") != null) {    // Use campaign parameters if available.
                EasyTracker.getTracker().setCampaign(uri.getPath());
            } else if (uri.getQueryParameter("referrer") != null) {    // Otherwise, try to find a referrer parameter.
                EasyTracker.getTracker().setReferrer(uri.getQueryParameter("referrer"));
            }
        }
    }

    private void initViewPager(Bundle savedInstanceState) {
        Intent intent = getIntent();
        if (AppScreenUtil.hasScreenInfo(intent)) {
            Screen screenInfo = AppScreenUtil.getScreenInfo(intent);
            switchToFragment(screenInfo);
        } else if (savedInstanceState == null) {
            mViewPager.setCurrentItem(1);
        }
    }
    
    private void setupViewPager() {
        // TODO: fixup
        mViewPager.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) {

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

            @Override
            public Fragment getItem(int position) {
                switch (position) {
                    case 0:
                        return new WeekendStatusViewerListFragment();
                    case 1:
                        return new LineStatusViewerListFragment();
                    case 2:
                        return new ViewAlertsFragment();
                    default:
                        return null;
                }
            }
            
            @Override
            public CharSequence getPageTitle(int position) {
                switch (position) {
                    case 0:
                        return "Weekend";
                    case 1:
                        return "Line Status";
                    case 2:
                        return "Alerts";
                    default:
                        return super.getPageTitle(position);
                }
            }
        });

        mViewPager.setOnPageChangeListener(new OnPageChangeListener() {

            @Override
            public void onPageSelected(int arg0) {
                invalidateOptionsMenu();
            }

            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
            }

            @Override
            public void onPageScrollStateChanged(int arg0) {
            }
        });

        int margin = getResources().getDimensionPixelSize(R.dimen.view_pager_page_margin);
        mViewPager.setPageMargin(margin);
        
        ViewCompat.setAccessibilityDelegate((View)mViewPagerIndicator, new AccessibilityDelegateCompat() {
            @Override
            public boolean dispatchPopulateAccessibilityEvent(View host, AccessibilityEvent event) {
                boolean ret = super.dispatchPopulateAccessibilityEvent(host, event);
                event.getText().add(0, "View Pager:");
                int currentItem = mViewPager.getCurrentItem();
                PagerAdapter adapter = mViewPager.getAdapter();
                event.getText().add(adapter.getPageTitle(currentItem));
                event.setCurrentItemIndex(currentItem);
                event.setItemCount(adapter.getCount());
                
                if(currentItem > 0) {
                    event.getText().add("Page to the left: "+adapter.getPageTitle(currentItem-1));
                }
                if(currentItem < adapter.getCount()-1) {
                    event.getText().add("Page to the right: "+adapter.getPageTitle(currentItem+1));
                }
                return ret;
            }
            
        });
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == android.R.id.home && BuildConfig.DEBUG) {
            Intent intent = new Intent(this, ExceptionViewerActivity.class);
            startActivity(intent);
            return true;
        } else {
            return super.onOptionsItemSelected(item);
        }
    }

    @Override
    protected boolean useDrawerIndicator() {
        return false;
    }

    @Override
    protected void onNavigationDrawerItemSelected(AppScreen item) {
        boolean consumed = switchToFragment(item.screen);
        // only call super if we haven't handled it ourselves
        if (!consumed) {
            super.onNavigationDrawerItemSelected(item);
        }
    }

    @Override
    protected Screen getCurrentScreen() {
        switch (mViewPager.getCurrentItem()) {
            case 0:
                return Screen.WEEKEND_STATUS;
            case 1:
                return Screen.CURRENT_STATUS;
            case 2:
                return Screen.LIST_OF_ALERTS;
        }
        return null;
    }

    private boolean switchToFragment(Screen screen) {
        boolean consumed = true;
        switch (screen) {
            case WEEKEND_STATUS:
                mViewPager.setCurrentItem(0);
                break;
            case CURRENT_STATUS:
                mViewPager.setCurrentItem(1);
                break;
            case LIST_OF_ALERTS:
                mViewPager.setCurrentItem(2);
                break;
            default:
                consumed = false;
        }

        return consumed;
    }
}