PagerTabHost.java

package com.kedzie.vbox.app;

import com.kedzie.vbox.SettingsActivity;

import android.content.Context;
import android.content.res.TypedArray;
import android.os.Parcel;
import android.os.Parcelable;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTabHost;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import android.widget.TabHost;
import android.widget.TabWidget;

/**
 *  Special {@link FragmentTabHost} which allows side-swiping.  
 *  When placing this in a view hierarchy, after inflating
 * the hierarchy you must call {@link #setup(Context, FragmentManager, int)}
 * to complete the initialization of the tab host.
 */
public class PagerTabHost extends TabHost implements TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener, TabSupport  {
    
    private FragPagerAdapter mAdapter;
    private ViewPager mRealTabContent;
    private int mContainerId;
    private DummyTabFactory mDummy;
    
    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 View(mContext);
            v.setMinimumWidth(0);
            v.setMinimumHeight(0);
            return v;
        }
    }

    static class SavedState extends BaseSavedState {
        String curTab;

        SavedState(Parcelable superState) {
            super(superState);
        }

        private SavedState(Parcel in) {
            super(in);
            curTab = in.readString();
        }

        @Override
        public void writeToParcel(Parcel out, int flags) {
            super.writeToParcel(out, flags);
            out.writeString(curTab);
        }

        @Override
        public String toString() {
            return "FragmentTabHost.SavedState{"
                    + Integer.toHexString(System.identityHashCode(this))
                    + " curTab=" + curTab + "}";
        }

        public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {
            public SavedState createFromParcel(Parcel in) {
                return new SavedState(in);
            }

            public SavedState[] newArray(int size) {
                return new SavedState[size];
            }
        };
    }

    public PagerTabHost(Context context) {
        // Note that we call through to the version that takes an AttributeSet,
        // because the simple Context construct can result in a broken object!
        super(context, null);
        initFragmentTabHost(context, null);
    }

    public PagerTabHost(Context context, AttributeSet attrs) {
        super(context, attrs);
        initFragmentTabHost(context, attrs);
    }

    private void initFragmentTabHost(Context context, AttributeSet attrs) {
        TypedArray a = context.obtainStyledAttributes(attrs,
                new int[] { android.R.attr.inflatedId }, 0, 0);
        mContainerId = a.getResourceId(0, 0);
        a.recycle();

        super.setOnTabChangedListener(this);
        mDummy = new DummyTabFactory(context);

        mAdapter = new FragPagerAdapter();
        
        // If owner hasn't made its own view hierarchy, then as a convenience
        // we will construct a standard one here.
        if (findViewById(android.R.id.tabs) == null) {
            LinearLayout ll = new LinearLayout(context);
            ll.setOrientation(LinearLayout.VERTICAL);
            addView(ll, new FrameLayout.LayoutParams(
                    ViewGroup.LayoutParams.MATCH_PARENT,
                    ViewGroup.LayoutParams.MATCH_PARENT));

            TabWidget tw = new TabWidget(context);
            tw.setId(android.R.id.tabs);
            tw.setOrientation(TabWidget.HORIZONTAL);
            ll.addView(tw, new LinearLayout.LayoutParams(
                    ViewGroup.LayoutParams.MATCH_PARENT,
                    ViewGroup.LayoutParams.WRAP_CONTENT, 0));

            FrameLayout fl = new FrameLayout(context);
            fl.setId(android.R.id.tabcontent);
            ll.addView(fl, new LinearLayout.LayoutParams(0, 0, 0));

            mRealTabContent = new ViewPager(context);
            mRealTabContent.setId(mContainerId);
            mRealTabContent.setOffscreenPageLimit(4);
            String transition = Utils.getStringPreference(getContext(), SettingsActivity.PREF_TAB_TRANSITION);
            if(transition.equals("Flip"))
                mRealTabContent.setPageTransformer(false, new FlipPageTransformer());
            else if(transition.equals("Slide"))
                mRealTabContent.setPageTransformer(false, new ZoomOutPageTransformer());
            
            ll.addView(mRealTabContent, new LinearLayout.LayoutParams(
                    LinearLayout.LayoutParams.MATCH_PARENT, 0, 1));
        }
    }
    
    /**
     * @deprecated Don't call the original TabHost setup, you must instead
     * call {@link #setup(Context, FragmentManager)} or
     * {@link #setup(Context, FragmentManager, int)}.
     */
    @Override @Deprecated
    public void setup() {
        throw new IllegalStateException("Must call setup() that takes a Context and FragmentManager");
    }

    public void setup(Context context, FragmentManager manager) {
        super.setup();
        ensureContent();
        mAdapter.setup(context, manager);
        mRealTabContent.setAdapter(mAdapter);
        mRealTabContent.setOnPageChangeListener(this);
    }

    public void setup(Context context, FragmentManager manager, int containerId) {
        super.setup();
        mContainerId = containerId;
        ensureContent();
        mRealTabContent.setId(containerId);
        mAdapter.setup(context, manager);
        mRealTabContent.setAdapter(mAdapter);
        mRealTabContent.setOnPageChangeListener(this);
        // We must have an ID to be able to save/restore our state.  If
        // the owner hasn't set one at this point, we will set it ourself.
        if (getId() == View.NO_ID) {
            setId(android.R.id.tabhost);
        }
    }

    private void ensureContent() {
        if (mRealTabContent == null) {
            mRealTabContent = (ViewPager)findViewById(mContainerId);
            if (mRealTabContent == null) {
                throw new IllegalStateException("No tab content FrameLayout found for id " + mContainerId);
            }
        }
    }
    
    @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 = getTabWidget();
        int oldFocusability = widget.getDescendantFocusability();
        widget.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
        setCurrentTab(position);
        widget.setDescendantFocusability(oldFocusability);
    }

    @Override
    public void onTabChanged(String tabId) {
        mRealTabContent.setCurrentItem(getCurrentTab());
    }
    
    @Override
    protected Parcelable onSaveInstanceState() {
        Parcelable superState = super.onSaveInstanceState();
        SavedState ss = new SavedState(superState);
        ss.curTab = getCurrentTabTag();
        return ss;
    }

    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        SavedState ss = (SavedState)state;
        super.onRestoreInstanceState(ss.getSuperState());
        setCurrentTabByTag(ss.curTab);
    }
    
    @Override
    public void addTab(FragmentElement tab) {
        TabSpec spec = newTabSpec(tab.name).setContent(mDummy);
        if(tab.icon!=-1)
            spec.setIndicator("", getResources().getDrawable(tab.icon));
        else
            spec.setIndicator(tab.name);
        addTab(spec);
        mAdapter.add(tab);
    }

    @Override
    public void removeTab(String name) {
        removeTab(name);
    }

    @Override
    public void removeAllTabs() {
        mAdapter.clear();
        clearAllTabs();
    }
    
    @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}
    @Override public void onPageScrollStateChanged(int state) {}
}