com.vandalsoftware.filter.PhotoPagerActivity.java Source code

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Here is the source code for com.vandalsoftware.filter.PhotoPagerActivity.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 com.vandalsoftware.filter;

import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentTransaction;
import android.content.Context;
import android.os.Bundle;
import android.support.v13.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;

import java.util.ArrayList;

/**
 * An Activity that displays a set of photos that can be paged or tabbed.
 */
public class PhotoPagerActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        final ViewPager viewPager = new ViewPager(this);
        viewPager.setId(R.id.pager);
        viewPager.setPageMargin((int) (getResources().getDisplayMetrics().density * 10));
        setContentView(viewPager);
        setTitle(R.string.app_name);

        final ActionBar bar = getActionBar();
        bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        bar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE);

        final TabsAdapter tabsAdapter = new TabsAdapter(this, viewPager);
        Bundle bundle;

        bundle = Bundle.EMPTY;
        tabsAdapter.addTab(bar.newTab().setText(R.string.no_filter), PhotoFragment.class, bundle);

        bundle = new Bundle();
        bundle.putInt(PhotoFragment.ARG_FILTER, PhotoFragment.FILTER_BW);
        tabsAdapter.addTab(bar.newTab().setText(R.string.bw_filter), PhotoFragment.class, bundle);

        bundle = new Bundle();
        bundle.putInt(PhotoFragment.ARG_FILTER, PhotoFragment.FILTER_CHILL);
        tabsAdapter.addTab(bar.newTab().setText(R.string.chill_filter), PhotoFragment.class, bundle);

        bundle = new Bundle();
        bundle.putInt(PhotoFragment.ARG_FILTER, PhotoFragment.FILTER_ROSE);
        tabsAdapter.addTab(bar.newTab().setText(R.string.rose_filter), PhotoFragment.class, bundle);

        bundle = new Bundle();
        bundle.putInt(PhotoFragment.ARG_FILTER, PhotoFragment.FILTER_INVERT);
        tabsAdapter.addTab(bar.newTab().setText(R.string.invert_filter), PhotoFragment.class, bundle);

        if (savedInstanceState != null) {
            bar.setSelectedNavigationItem(savedInstanceState.getInt("tab", 0));
        }
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("tab", getActionBar().getSelectedNavigationIndex());
    }

    /**
     * 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 static class TabsAdapter extends FragmentPagerAdapter
            implements ActionBar.TabListener, ViewPager.OnPageChangeListener {
        private final Context mContext;
        private final ActionBar mActionBar;
        private final ViewPager mViewPager;
        private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();

        public TabsAdapter(Activity activity, ViewPager pager) {
            super(activity.getFragmentManager());
            mContext = activity;
            mActionBar = activity.getActionBar();
            mViewPager = pager;
            mViewPager.setAdapter(this);
            mViewPager.setOnPageChangeListener(this);
        }

        public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) {
            TabInfo info = new TabInfo(clss, args);
            tab.setTag(info);
            tab.setTabListener(this);
            mTabs.add(info);
            mActionBar.addTab(tab);
            notifyDataSetChanged();
        }

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

        @Override
        public Fragment getItem(int position) {
            TabInfo info = mTabs.get(position);
            return Fragment.instantiate(mContext, info.clss.getName(), info.args);
        }

        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
        }

        @Override
        public void onPageSelected(int position) {
            mActionBar.setSelectedNavigationItem(position);
        }

        @Override
        public void onPageScrollStateChanged(int state) {
        }

        @Override
        public void onTabSelected(Tab tab, FragmentTransaction ft) {
            Object tag = tab.getTag();
            for (int i = 0; i < mTabs.size(); i++) {
                if (mTabs.get(i) == tag) {
                    mViewPager.setCurrentItem(i);
                }
            }
        }

        @Override
        public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        }

        @Override
        public void onTabReselected(Tab tab, FragmentTransaction ft) {
        }

        public static final class TabInfo {
            private final Class<?> clss;
            private final Bundle args;

            public TabInfo(Class<?> _class, Bundle _args) {
                clss = _class;
                args = _args;
            }
        }
    }
}