au.com.connectedteam.adapter.CustomFragmentPagerAdapter.java Source code

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Here is the source code for au.com.connectedteam.adapter.CustomFragmentPagerAdapter.java

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/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * 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 au.com.connectedteam.adapter;

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.util.Log;
import android.view.View;
import android.view.ViewGroup;

/**
 * Custom implementation of android.support.v4.view.PagerAdapter, with new method 
 * getExistingFragment
 */
public abstract class CustomFragmentPagerAdapter extends PagerAdapter implements MultiPagerAdapter {
    private static final String TAG = "CFragmentPagerAdapter";
    private static final boolean DEBUG = false;

    private final FragmentManager mFragmentManager;
    private FragmentTransaction mCurTransaction = null;
    private Fragment mCurrentPrimaryItem = null;

    public int mContainerId;

    public CustomFragmentPagerAdapter(FragmentManager fm) {
        mFragmentManager = fm;
    }

    /**
     * Create the Fragment associated with a specified position.
     */
    public abstract Fragment makeFragment(int position);

    /**
     * Get a fragment that has already been created, if it exists. Else null.
     * @param position
     * @return
     */
    public Fragment getExistingFragment(int position) {
        final long itemId = getItemId(position);

        // Do we already have this fragment?
        String name = makeFragmentName(mContainerId, itemId);
        return mFragmentManager.findFragmentByTag(name);

    }

    @Override
    public int getViewsPerPage() {

        return 1;
    }

    @Override
    public float getPageWidth(int position) {

        //Margins are 1% wide,         
        int numMargins = getViewsPerPage() - 1;
        if (numMargins == 0)
            return 1;
        return (1f / getViewsPerPage()) * (1f - (numMargins / 100f));
    }

    @Override
    public void startUpdate(ViewGroup container) {
    }

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

        final long itemId = getItemId(position);

        // Do we already have this fragment?
        String name = makeFragmentName(container.getId(), itemId);
        Fragment fragment = mFragmentManager.findFragmentByTag(name);
        if (fragment != null) {
            if (DEBUG)
                Log.v(TAG, "Attaching item #" + itemId + ": f=" + fragment);
            mCurTransaction.attach(fragment);
        } else {
            fragment = makeFragment(position);
            if (DEBUG)
                Log.v(TAG, "Adding item #" + itemId + ": f=" + fragment);
            mCurTransaction.add(container.getId(), fragment, makeFragmentName(container.getId(), itemId));
        }
        if (fragment != mCurrentPrimaryItem) {
            fragment.setMenuVisibility(false);
            fragment.setUserVisibleHint(false);
        }

        return fragment;
    }

    public void duck(boolean hide) {

        if (mCurrentPrimaryItem != null) {

            mCurrentPrimaryItem.setMenuVisibility(!hide);
            mCurrentPrimaryItem.setUserVisibleHint(!hide);
        }
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        if (mCurTransaction == null) {
            mCurTransaction = mFragmentManager.beginTransaction();
        }
        if (DEBUG)
            Log.v(TAG, "Detaching item #" + getItemId(position) + ": f=" + object + " v="
                    + ((Fragment) object).getView());
        mCurTransaction.detach((Fragment) object);
    }

    /**
     * DestroyItem only detatches the fragment, it stays in the fragment manager. This fully removes any fragments it has previously added.
     */
    public void removeAllFragments() {
        boolean needToFinish = mCurTransaction == null;
        if (mCurTransaction == null) {
            mCurTransaction = mFragmentManager.beginTransaction();
        }
        for (int i = 0; i < getCount(); i++) {
            Fragment fragment = getExistingFragment(i);
            if (fragment != null) {
                mCurTransaction.remove(fragment);
            }
        }

        if (needToFinish) {
            mCurTransaction.commitAllowingStateLoss();
            //mCurTransaction=null;
        }

    }

    @Override
    public void setPrimaryItem(ViewGroup container, int position, Object object) {
        Fragment fragment = (Fragment) object;
        if (fragment != mCurrentPrimaryItem) {
            if (mCurrentPrimaryItem != null) {
                mCurrentPrimaryItem.setMenuVisibility(false);
                mCurrentPrimaryItem.setUserVisibleHint(false);
            }
            if (fragment != null) {
                fragment.setMenuVisibility(true);
                fragment.setUserVisibleHint(true);
            }
            mCurrentPrimaryItem = fragment;
        }
    }

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

    public int getItemPosition(Object object) {
        return POSITION_UNCHANGED;
    }

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

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

    @Override
    public void restoreState(Parcelable state, ClassLoader loader) {
    }

    /**
     * Return a unique identifier for the item at the given position.
     *
     * <p>The default implementation returns the given position.
     * Subclasses should override this method if the positions of items can change.</p>
     *
     * @param position Position within this adapter
     * @return Unique identifier for the item at position
     */
    public long getItemId(int position) {
        return position;
    }

    protected String makeFragmentName(int viewId, long id) {
        return "android:switcher:" + this.getClass().getSimpleName() + viewId + ":" + id;
    }
}