com.flc.app3.utils.FragmentPagerItemAdapter.java Source code

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Here is the source code for com.flc.app3.utils.FragmentPagerItemAdapter.java

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/**
 * Copyright (C) 2015 ogaclejapan
 *
 * 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.flc.app3.utils;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.util.SparseArrayCompat;
import android.view.ViewGroup;

import java.lang.ref.WeakReference;

public class FragmentPagerItemAdapter extends FragmentPagerAdapter {

    private final FragmentPagerItems pages;
    private final SparseArrayCompat<WeakReference<Fragment>> holder;

    public FragmentPagerItemAdapter(FragmentManager fm, FragmentPagerItems pages) {
        super(fm);
        this.pages = pages;
        this.holder = new SparseArrayCompat<>(pages.size());
    }

    @Override
    public int getCount() {
        return pages.size();
    }

    @Override
    public Fragment getItem(int position) {
        return getPagerItem(position).instantiate(pages.getContext(), position);
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        Object item = super.instantiateItem(container, position);
        if (item instanceof Fragment) {
            holder.put(position, new WeakReference<Fragment>((Fragment) item));
        }
        return item;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        holder.remove(position);
        super.destroyItem(container, position, object);
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return getPagerItem(position).getTitle();
    }

    @Override
    public float getPageWidth(int position) {
        return super.getPageWidth(position);
    }

    public Fragment getPage(int position) {
        final WeakReference<Fragment> weakRefItem = holder.get(position);
        return (weakRefItem != null) ? weakRefItem.get() : null;
    }

    protected FragmentPagerItem getPagerItem(int position) {
        return pages.get(position);
    }

}