Java tutorial
/* * Copyright (C) 2012 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.dhl.android.bitmapfun.ui; import android.app.ActionBar; import android.content.Intent; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentActivity; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentStatePagerAdapter; import android.support.v4.view.ViewPager; import android.util.DisplayMetrics; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.view.View.OnClickListener; import android.view.ViewGroup; import android.view.WindowManager.LayoutParams; import android.widget.Toast; import com.dhl.android.bitmapfun.provider.Images; import com.dhl.android.bitmapfun.util.DiskLruCache; import com.dhl.android.bitmapfun.util.ImageCache; import com.dhl.android.bitmapfun.util.ImageFetcher; import com.dhl.android.bitmapfun.util.ImageResizer; import com.dhl.android.bitmapfun.util.ImageWorker; import com.dhl.android.bitmapfun.util.Utils; import com.dhl.template.R; public class ImageDetailActivity extends FragmentActivity implements OnClickListener { private static final String IMAGE_CACHE_DIR = "images"; public static final String EXTRA_IMAGE = "extra_image"; private ImagePagerAdapter mAdapter; private ImageResizer mImageWorker; private ViewPager mPager; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.image_detail_pager); // Fetch screen height and width, to use as our max size when loading images as this // activity runs full screen final DisplayMetrics displaymetrics = new DisplayMetrics(); getWindowManager().getDefaultDisplay().getMetrics(displaymetrics); final int height = displaymetrics.heightPixels; final int width = displaymetrics.widthPixels; final int longest = height > width ? height : width; // The ImageWorker takes care of loading images into our ImageView children asynchronously mImageWorker = new ImageFetcher(this, longest); mImageWorker.setAdapter(Images.imageWorkerUrlsAdapter); mImageWorker.setImageCache(ImageCache.findOrCreateCache(this, IMAGE_CACHE_DIR)); mImageWorker.setImageFadeIn(false); // Set up ViewPager and backing adapter mAdapter = new ImagePagerAdapter(getSupportFragmentManager(), mImageWorker.getAdapter().getSize()); mPager = (ViewPager) findViewById(R.id.pager); mPager.setAdapter(mAdapter); mPager.setPageMargin((int) getResources().getDimension(R.dimen.image_detail_pager_margin)); // Set up activity to go full screen getWindow().addFlags(LayoutParams.FLAG_FULLSCREEN); // Enable some additional newer visibility and ActionBar features to create a more immersive // photo viewing experience if (Utils.hasActionBar()) { final ActionBar actionBar = getActionBar(); // Enable "up" navigation on ActionBar icon and hide title text actionBar.setDisplayHomeAsUpEnabled(true); actionBar.setDisplayShowTitleEnabled(false); // Start low profile mode and hide ActionBar mPager.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE); actionBar.hide(); // Hide and show the ActionBar as the visibility changes mPager.setOnSystemUiVisibilityChangeListener(new View.OnSystemUiVisibilityChangeListener() { @Override public void onSystemUiVisibilityChange(int vis) { if ((vis & View.SYSTEM_UI_FLAG_LOW_PROFILE) != 0) { actionBar.hide(); } else { actionBar.show(); } } }); } // Set the current item based on the extra passed in to this activity final int extraCurrentItem = getIntent().getIntExtra(EXTRA_IMAGE, -1); if (extraCurrentItem != -1) { mPager.setCurrentItem(extraCurrentItem); } } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case android.R.id.home: // Home or "up" navigation final Intent intent = new Intent(this, ImageGridActivity.class); intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); startActivity(intent); return true; case R.id.clear_cache: final ImageCache cache = mImageWorker.getImageCache(); if (cache != null) { mImageWorker.getImageCache().clearCaches(); DiskLruCache.clearCache(this, ImageFetcher.HTTP_CACHE_DIR); Toast.makeText(this, R.string.clear_cache_complete, Toast.LENGTH_SHORT).show(); } return true; } return super.onOptionsItemSelected(item); } @Override public boolean onCreateOptionsMenu(Menu menu) { MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.main_menu, menu); return true; } /** * Called by the ViewPager child fragments to load images via the one ImageWorker * * @return */ public ImageWorker getImageWorker() { return mImageWorker; } /** * The main adapter that backs the ViewPager. A subclass of FragmentStatePagerAdapter as there * could be a large number of items in the ViewPager and we don't want to retain them all in * memory at once but create/destroy them on the fly. */ private class ImagePagerAdapter extends FragmentStatePagerAdapter { private final int mSize; public ImagePagerAdapter(FragmentManager fm, int size) { super(fm); mSize = size; } @Override public int getCount() { return mSize; } @Override public Fragment getItem(int position) { return ImageDetailFragment.newInstance(position); } @Override public void destroyItem(ViewGroup container, int position, Object object) { final ImageDetailFragment fragment = (ImageDetailFragment) object; // As the item gets destroyed we try and cancel any existing work. fragment.cancelWork(); super.destroyItem(container, position, object); } } /** * Set on the ImageView in the ViewPager children fragments, to enable/disable low profile mode * when the ImageView is touched. */ @Override public void onClick(View v) { final int vis = mPager.getSystemUiVisibility(); if ((vis & View.SYSTEM_UI_FLAG_LOW_PROFILE) != 0) { mPager.setSystemUiVisibility(View.SYSTEM_UI_FLAG_VISIBLE); } else { mPager.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE); } } }