com.gandulf.guilib.view.adapter.MultiFragmentPagerAdapter.java Source code

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Here is the source code for com.gandulf.guilib.view.adapter.MultiFragmentPagerAdapter.java

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/*
 * Copyright (C) 2010 Gandulf Kohlweiss
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.gandulf.guilib.view.adapter;

import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.os.Parcelable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import android.widget.LinearLayout.LayoutParams;

import com.gandulf.guilib.util.Debug;

/**
 * @author Ganymede
 * 
 */
public abstract class MultiFragmentPagerAdapter extends PagerAdapter {

    protected List<Fragment> mCurrentPrimaryItems = new ArrayList<Fragment>();

    protected FragmentManager mFragmentManager;
    protected FragmentTransaction mCurTransaction;

    protected Context mContext;

    public MultiFragmentPagerAdapter(Context context, FragmentManager fm) {
        super();
        this.mContext = context;
        this.mFragmentManager = fm;
    }

    public abstract Fragment getItem(int position, int tab);

    public abstract int getCount();

    public abstract int getCount(int position);

    @Override
    public Object instantiateItem(View container, int position) {
        if (mCurTransaction == null) {
            mCurTransaction = mFragmentManager.beginTransaction();
        }

        LinearLayout v = new LinearLayout(mContext);
        v.setOrientation(LinearLayout.HORIZONTAL);
        v.setWeightSum(getCount(position));

        int startIndex = getStartIndex(position);

        int containerId = 0;
        final int size = getCount(position);
        for (int i = 0; i < size; i++) {

            containerId = startIndex + i;

            String name = makeFragmentName(container.getId(), containerId);
            Fragment fragment = mFragmentManager.findFragmentByTag(name);

            FrameLayout fragmentView = new FrameLayout(mContext);
            LayoutParams layoutParams = new LayoutParams(0, LayoutParams.MATCH_PARENT, 1);
            fragmentView.setLayoutParams(layoutParams);
            fragmentView.setId(containerId);
            v.addView(fragmentView, i);

            if (fragment != null) {
                Debug.verbose("Attaching item #" + position + ": f=" + fragment + " id:" + containerId);
                mCurTransaction.attach(fragment);
            } else {
                // index is 1 based remove 1 to get a 0-based
                fragment = getItem(position, i);
                if (fragment != null) {
                    Debug.verbose("Adding item #" + position + ": f=" + fragment + " id:" + containerId);
                    mCurTransaction.add(containerId, fragment, name);
                }
            }
            if (fragment != null && !mCurrentPrimaryItems.contains(fragment)) {
                fragment.setMenuVisibility(false);
                fragment.setUserVisibleHint(false);
            }
        }

        mCurTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);

        ((ViewPager) container).addView(v, 0);

        return v;
    }

    @Override
    public void destroyItem(View container, int position, Object object) {
        if (mCurTransaction == null) {
            mCurTransaction = mFragmentManager.beginTransaction();
        }
        int containerId = 0;
        final int startIndex = getStartIndex(position);
        final int size = getCount(position);
        for (int i = 0; i < size; i++) {
            containerId = startIndex + i;
            String name = makeFragmentName(container.getId(), containerId);
            Fragment fragment = mFragmentManager.findFragmentByTag(name);
            if (fragment != null) {
                Debug.verbose("Detaching item #" + position + ": f=" + object + " v=" + fragment.getView());
                mCurTransaction.detach(fragment);
            }
        }

        ((ViewPager) container).removeView((LinearLayout) object);
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == ((LinearLayout) object);
    }

    @Override
    public void setPrimaryItem(View container, int position, Object object) {

        List<Fragment> newPrimaryItems = new ArrayList<Fragment>(getCount(position));
        int containerId = 0;
        final int startIndex = getStartIndex(position);
        final int size = getCount(position);
        for (int i = 0; i < size; i++) {

            containerId = startIndex + i;
            String name = makeFragmentName(container.getId(), containerId);
            Fragment fragment = mFragmentManager.findFragmentByTag(name);
            if (fragment != null) {
                newPrimaryItems.add(fragment);
            }

        }

        mCurrentPrimaryItems.removeAll(newPrimaryItems);
        for (Fragment frag : mCurrentPrimaryItems) {
            frag.setMenuVisibility(false);
            frag.setUserVisibleHint(false);
        }

        for (Fragment frag : newPrimaryItems) {
            frag.setMenuVisibility(true);
            frag.setUserVisibleHint(true);
        }

        mCurrentPrimaryItems = newPrimaryItems;

    }

    @Override
    public void finishUpdate(View container) {
        if (mCurTransaction != null) {
            mCurTransaction.commitAllowingStateLoss();
            mCurTransaction = null;
            mFragmentManager.executePendingTransactions();
        }
    }

    @Override
    public Parcelable saveState() {
        return null;
    }

    @Override
    public void startUpdate(View arg0) {
    }

    @Override
    public void restoreState(Parcelable arg0, ClassLoader arg1) {
    }

    protected String makeFragmentName(int viewId, int position) {
        return "android:switcher:" + viewId + ":" + position;
    }

    protected int getStartIndex(int position) {
        int index = 1;
        for (int i = 0; i < position; i++) {
            index += getCount(i);
        }
        return index;

    }

}