package com.papagiannis.tuberun;
import java.util.ArrayList;
import java.util.Locale;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TabHost;
import android.widget.TabWidget;
import android.widget.TextView;
/**
* This is a helper class that implements the management of tabs and all details
* of connecting a ViewPager with associated TabHost. It relies on a trick.
* Normally a tab host has a simple API for supplying a View or Intent that each
* tab will show. This is not sufficient for switching between pages. So instead
* we make the content part of the tab host 0dp high (it is not shown) and the
* TabsAdapter supplies its own dummy view to show as the tab content. It
* listens to changes in tabs, and takes care of switch to the correct paged in
* the ViewPager whenever the selected tab changes.
*/
public class TabsAdapter extends FragmentPagerAdapter implements
TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener {
private final Context mContext;
private final TabHost mTabHost;
private final ViewPager mViewPager;
private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
private final ArrayList<Fragment> mPastFragments = new ArrayList<Fragment>();
static final class TabInfo {
private final Class<?> clss;
private final Bundle args;
TabInfo(Class<?> _class, Bundle _args) {
clss = _class;
args = _args;
}
}
static class DummyTabFactory implements TabHost.TabContentFactory {
private final Context mContext;
public DummyTabFactory(Context context) {
mContext = context;
}
@Override
public View createTabContent(String tag) {
View v = new TextView(mContext);
v.setMinimumWidth(0);
v.setMinimumHeight(0);
return v;
}
}
public TabsAdapter(FragmentActivity activity, TabHost tabHost,
ViewPager pager) {
super(activity.getSupportFragmentManager());
mContext = activity;
mTabHost = tabHost;
mViewPager = pager;
mTabHost.setOnTabChangedListener(this);
mViewPager.setAdapter(this);
mViewPager.setOnPageChangeListener(this);
}
public void addTab(TabHost.TabSpec tabSpec, Class<?> clss, Bundle args) {
String tag = tabSpec.getTag();
tabSpec.setContent(new DummyTabFactory(mContext));
tabSpec.setIndicator(createTabView(mContext, tag));
TabInfo info = new TabInfo(clss, args);
mTabs.add(info);
mTabHost.addTab(tabSpec);
notifyDataSetChanged();
}
@Override
public int getCount() {
return mTabs.size();
}
@Override
public Fragment getItem(int position) {
TabInfo info = mTabs.get(position);
Fragment res = null;
if (mPastFragments.size() > position)
res = mPastFragments.get(position);
else {
res = Fragment
.instantiate(mContext, info.clss.getName(), info.args);
mPastFragments.add(position, res);
}
return res;
}
@Override
public void onTabChanged(String tabId) {
int position = mTabHost.getCurrentTab();
mViewPager.setCurrentItem(position);
}
@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
// Unfortunately when TabHost changes the current tab, it kindly
// also takes care of putting focus on it when not in touch mode.
// The jerk.
// This hack tries to prevent this from pulling focus out of our
// ViewPager.
TabWidget widget = mTabHost.getTabWidget();
int oldFocusability = widget.getDescendantFocusability();
widget.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
mTabHost.setCurrentTab(position);
widget.setDescendantFocusability(oldFocusability);
}
@Override
public void onPageScrollStateChanged(int state) {
}
private TextView tabsTextView;
private ImageView tabsImageView;
public View createTabView(final Context context, final String text) {
View view = LayoutInflater.from(context)
.inflate(R.layout.tabs_background, null);
tabsTextView = (TextView) view.findViewById(R.id.tabs_textview);
tabsTextView.setText(text.toUpperCase(Locale.ENGLISH));
tabsImageView = (ImageView) view.findViewById(R.id.tabs_imageview);
return view;
}
public TextView getTabsTextView() {
return tabsTextView;
}
public ImageView getTabsImageView() {
return tabsImageView;
}
}