Java tutorial
package org.wikipedia.gallery; import android.app.Activity; import android.app.DownloadManager; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.graphics.Bitmap; import android.net.Uri; import android.os.Bundle; import android.support.annotation.ColorInt; import android.support.annotation.ColorRes; import android.support.annotation.NonNull; import android.support.annotation.Nullable; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentPagerAdapter; import android.support.v4.app.FragmentTransaction; import android.support.v4.content.ContextCompat; import android.support.v4.view.ViewPager; import android.support.v7.app.AppCompatActivity; import android.support.v7.widget.Toolbar; import android.text.TextUtils; import android.util.SparseArray; import android.view.Gravity; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; import android.widget.ProgressBar; import android.widget.TextView; import org.wikipedia.R; import org.wikipedia.WikipediaApp; import org.wikipedia.activity.BaseActivity; import org.wikipedia.analytics.GalleryFunnel; import org.wikipedia.concurrency.CallbackTask; import org.wikipedia.dataclient.WikiSite; import org.wikipedia.feed.image.FeaturedImage; import org.wikipedia.history.HistoryEntry; import org.wikipedia.json.GsonMarshaller; import org.wikipedia.json.GsonUnmarshaller; import org.wikipedia.page.ExclusiveBottomSheetPresenter; import org.wikipedia.page.LinkMovementMethodExt; import org.wikipedia.page.PageActivity; import org.wikipedia.page.PageTitle; import org.wikipedia.page.linkpreview.LinkPreviewDialog; import org.wikipedia.readinglist.AddToReadingListDialog; import org.wikipedia.theme.Theme; import org.wikipedia.util.ClipboardUtil; import org.wikipedia.util.FeedbackUtil; import org.wikipedia.util.GradientUtil; import org.wikipedia.util.ShareUtil; import org.wikipedia.util.StringUtil; import org.wikipedia.util.log.L; import org.wikipedia.views.ViewAnimations; import org.wikipedia.views.WikiErrorView; import java.io.File; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import static org.wikipedia.util.StringUtil.addUnderscores; import static org.wikipedia.util.StringUtil.strip; import static org.wikipedia.util.UriUtil.handleExternalLink; import static org.wikipedia.util.UriUtil.resolveProtocolRelativeUrl; public class GalleryActivity extends BaseActivity implements LinkPreviewDialog.Callback, GalleryItemFragment.Callback { public static final int ACTIVITY_RESULT_PAGE_SELECTED = 1; public static final String EXTRA_PAGETITLE = "pageTitle"; public static final String EXTRA_FILENAME = "filename"; public static final String EXTRA_WIKI = "wiki"; public static final String EXTRA_SOURCE = "source"; public static final String EXTRA_FEATURED_IMAGE = "featuredImage"; public static final String EXTRA_FEATURED_IMAGE_AGE = "featuredImageAge"; @NonNull private WikipediaApp app = WikipediaApp.getInstance(); @NonNull private ExclusiveBottomSheetPresenter bottomSheetPresenter = new ExclusiveBottomSheetPresenter(); @Nullable private PageTitle pageTitle; @Nullable private WikiSite wiki; @NonNull private GalleryCollectionClient client = new GalleryCollectionClient(); private ViewGroup toolbarContainer; private ViewGroup infoContainer; private ProgressBar progressBar; private TextView descriptionText; private ImageView licenseIcon; private TextView creditText; private WikiErrorView errorView; private boolean controlsShowing = true; @Nullable private ViewPager.OnPageChangeListener pageChangeListener; @Nullable private GalleryFunnel funnel; /** * If we have an intent that tells us a specific image to jump to within the gallery, * then this will be non-null. */ private String initialFilename; /** * If we come back from savedInstanceState, then this will be the previous pager position. */ private int initialImageIndex = -1; private ViewPager galleryPager; private GalleryItemAdapter galleryAdapter; private MediaDownloadReceiver downloadReceiver = new MediaDownloadReceiver(); private MediaDownloadReceiverCallback downloadReceiverCallback = new MediaDownloadReceiverCallback(); /** * Cache that stores GalleryItem information for each corresponding media item in * our gallery collection. */ @Nullable private Map<PageTitle, GalleryItem> galleryCache; @Nullable public Map<PageTitle, GalleryItem> getGalleryCache() { return galleryCache; } private View.OnClickListener licenseShortClickListener = new View.OnClickListener() { @Override public void onClick(View v) { if (v.getContentDescription() == null) { return; } FeedbackUtil.showMessageAsPlainText((Activity) v.getContext(), v.getContentDescription()); } }; private View.OnLongClickListener licenseLongClickListener = new View.OnLongClickListener() { @Override public boolean onLongClick(View v) { String licenseUrl = (String) v.getTag(); if (!TextUtils.isEmpty(licenseUrl)) { handleExternalLink(GalleryActivity.this, Uri.parse(resolveProtocolRelativeUrl(licenseUrl))); } return true; } }; @NonNull public static Intent newIntent(@NonNull Context context, int age, @NonNull String filename, @NonNull FeaturedImage image, @NonNull WikiSite wiki, int source) { return newIntent(context, null, filename, wiki, source) .putExtra(EXTRA_FEATURED_IMAGE, GsonMarshaller.marshal(image)) .putExtra(EXTRA_FEATURED_IMAGE_AGE, age); } @NonNull public static Intent newIntent(@NonNull Context context, @Nullable PageTitle pageTitle, @NonNull String filename, @NonNull WikiSite wiki, int source) { Intent intent = new Intent().setClass(context, GalleryActivity.class).putExtra(EXTRA_FILENAME, filename) .putExtra(EXTRA_WIKI, wiki).putExtra(EXTRA_SOURCE, source); if (pageTitle != null) { intent.putExtra(EXTRA_PAGETITLE, pageTitle); } return intent; } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_gallery); initToolbar(); toolbarContainer = findViewById(R.id.gallery_toolbar_container); infoContainer = findViewById(R.id.gallery_info_container); setBackgroundGradient(infoContainer, Gravity.BOTTOM); progressBar = findViewById(R.id.gallery_progressbar); descriptionText = findViewById(R.id.gallery_description_text); descriptionText.setShadowLayer(2, 1, 1, color(R.color.black54)); descriptionText.setMovementMethod(linkMovementMethod); licenseIcon = findViewById(R.id.gallery_license_icon); licenseIcon.setOnClickListener(licenseShortClickListener); licenseIcon.setOnLongClickListener(licenseLongClickListener); creditText = findViewById(R.id.gallery_credit_text); creditText.setShadowLayer(2, 1, 1, color(R.color.black54)); errorView = findViewById(R.id.view_gallery_error); ((ImageView) errorView.findViewById(R.id.view_wiki_error_icon)).setColorFilter(color(R.color.base70)); ((TextView) errorView.findViewById(R.id.view_wiki_error_text)).setTextColor(color(R.color.base70)); errorView.setBackClickListener(new View.OnClickListener() { @Override public void onClick(View v) { onBackPressed(); } }); errorView.setRetryClickListener(new View.OnClickListener() { @Override public void onClick(View v) { errorView.setVisibility(View.GONE); loadGalleryContent(); } }); if (getIntent().hasExtra(EXTRA_PAGETITLE)) { pageTitle = getIntent().getParcelableExtra(EXTRA_PAGETITLE); } initialFilename = getIntent().getStringExtra(EXTRA_FILENAME); wiki = getIntent().getParcelableExtra(EXTRA_WIKI); galleryCache = new HashMap<>(); galleryAdapter = new GalleryItemAdapter(this); galleryPager = findViewById(R.id.gallery_item_pager); galleryPager.setAdapter(galleryAdapter); pageChangeListener = new GalleryPageChangeListener(); galleryPager.addOnPageChangeListener(pageChangeListener); funnel = new GalleryFunnel(app, wiki, getIntent().getIntExtra(EXTRA_SOURCE, 0)); if (savedInstanceState == null) { if (initialFilename != null) { funnel.logGalleryOpen(pageTitle, initialFilename); } } else { controlsShowing = savedInstanceState.getBoolean("controlsShowing"); initialImageIndex = savedInstanceState.getInt("pagerIndex"); // if we have a savedInstanceState, then the initial index overrides // the initial Title from our intent. initialFilename = null; FragmentManager fm = getSupportFragmentManager(); if (getSupportFragmentManager().getBackStackEntryCount() > 0) { FragmentTransaction ft = getSupportFragmentManager().beginTransaction(); for (int i = 0; i < fm.getBackStackEntryCount(); i++) { Fragment fragment = fm.findFragmentById(fm.getBackStackEntryAt(i).getId()); if (fragment instanceof GalleryItemFragment) { ft.remove(fragment); } } ft.commitAllowingStateLoss(); } } toolbarContainer.post(new Runnable() { @Override public void run() { setControlsShowing(controlsShowing); } }); loadGalleryContent(); } @Override public void onDestroy() { galleryPager.removeOnPageChangeListener(pageChangeListener); pageChangeListener = null; super.onDestroy(); } private void loadGalleryItemFor(@NonNull FeaturedImage image, int age) { List<GalleryItem> list = new ArrayList<>(); list.add(new FeaturedImageGalleryItem(image, age)); applyGalleryCollection(new GalleryCollection(list)); } @Override public void onResume() { super.onResume(); registerReceiver(downloadReceiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE)); downloadReceiver.setCallback(downloadReceiverCallback); } @Override public void onPause() { super.onPause(); downloadReceiver.setCallback(null); unregisterReceiver(downloadReceiver); } @Override public void onDownload(@NonNull GalleryItem item) { funnel.logGallerySave(pageTitle, item.getName()); downloadReceiver.download(this, item); FeedbackUtil.showMessage(this, R.string.gallery_save_progress); } @Override public void onShare(@NonNull GalleryItem item, @Nullable Bitmap bitmap, @NonNull String subject, @NonNull PageTitle title) { funnel.logGalleryShare(pageTitle, item.getName()); if (bitmap != null) { ShareUtil.shareImage(this, bitmap, new File(item.getUrl()).getName(), subject, title.getCanonicalUri()); } else { ShareUtil.shareText(this, title); } } @Override protected void setTheme() { setTheme(Theme.DARK.getResourceId()); } private class GalleryPageChangeListener extends ViewPager.SimpleOnPageChangeListener { private int currentPosition = -1; @Override public void onPageSelected(int position) { // the pager has settled on a new position layOutGalleryDescription(); galleryAdapter.notifyFragments(position); if (currentPosition != -1 && getCurrentItem() != null) { if (position < currentPosition) { funnel.logGallerySwipeLeft(pageTitle, getCurrentItem().getName()); } else if (position > currentPosition) { funnel.logGallerySwipeRight(pageTitle, getCurrentItem().getName()); } } currentPosition = position; } @Override public void onPageScrollStateChanged(int state) { if (state == ViewPager.SCROLL_STATE_IDLE) { galleryAdapter.purgeFragments(false); } } } @Override protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putBoolean("controlsShowing", controlsShowing); outState.putInt("pagerIndex", galleryPager.getCurrentItem()); } private void updateProgressBar(boolean visible, boolean indeterminate, int value) { progressBar.setIndeterminate(indeterminate); if (!indeterminate) { progressBar.setProgress(value); } progressBar.setVisibility(visible ? View.VISIBLE : View.GONE); } @Override public void onBackPressed() { // log the "gallery close" event only upon explicit closing of the activity // (back button, or home-as-up button in the toolbar) if (getCurrentItem() != null) { funnel.logGalleryClose(pageTitle, getCurrentItem().getName()); } super.onBackPressed(); } /** * Show or hide all the UI controls in this activity (slide them out or in). * @param showing Whether to show or hide the controls. */ private void setControlsShowing(boolean showing) { controlsShowing = showing; if (controlsShowing) { ViewAnimations.ensureTranslationY(toolbarContainer, 0); ViewAnimations.ensureTranslationY(infoContainer, 0); } else { ViewAnimations.ensureTranslationY(toolbarContainer, -toolbarContainer.getHeight()); ViewAnimations.ensureTranslationY(infoContainer, infoContainer.getHeight()); } } /** * Toggle showing or hiding of all the UI controls. */ public void toggleControls() { setControlsShowing(!controlsShowing); } public void showLinkPreview(@NonNull PageTitle title) { bottomSheetPresenter.show(getSupportFragmentManager(), LinkPreviewDialog.newInstance(title, HistoryEntry.SOURCE_GALLERY, null)); } /** * LinkMovementMethod for handling clicking of links in the description or metadata * text fields. For internal links, this activity will close, and pass the page title as * the result. For external links, they will be bounced out to the Browser. */ private LinkMovementMethodExt linkMovementMethod = new LinkMovementMethodExt( new LinkMovementMethodExt.UrlHandler() { @Override public void onUrlClick(@NonNull String url, @Nullable String notUsed) { L.v("Link clicked was " + url); url = resolveProtocolRelativeUrl(url); if (url.startsWith("/wiki/")) { PageTitle title = app.getWikiSite().titleForInternalLink(url); showLinkPreview(title); } else { Uri uri = Uri.parse(url); String authority = uri.getAuthority(); if (authority != null && WikiSite.supportedAuthority(authority) && uri.getPath().startsWith("/wiki/")) { PageTitle title = new WikiSite(uri).titleForUri(uri); showLinkPreview(title); } else { // if it's a /w/ URI, turn it into a full URI and go external if (url.startsWith("/w/")) { url = String.format("%1$s://%2$s", app.getWikiSite().scheme(), app.getWikiSite().authority()) + url; } handleExternalLink(GalleryActivity.this, Uri.parse(url)); } } } }); /** * Close this activity, with the specified PageTitle as the activity result, to be picked up * by the activity that originally launched us. * @param resultTitle PageTitle to pass as the activity result. */ public void finishWithPageResult(@NonNull PageTitle resultTitle) { finishWithPageResult(resultTitle, new HistoryEntry(resultTitle, HistoryEntry.SOURCE_GALLERY)); } public void finishWithPageResult(@NonNull PageTitle resultTitle, @NonNull HistoryEntry historyEntry) { Intent intent = PageActivity.newIntentForCurrentTab(GalleryActivity.this, historyEntry, resultTitle); setResult(ACTIVITY_RESULT_PAGE_SELECTED, intent); finish(); } @Override public void onLinkPreviewLoadPage(@NonNull PageTitle title, @NonNull HistoryEntry entry, boolean inNewTab) { finishWithPageResult(title, entry); } @Override public void onLinkPreviewCopyLink(@NonNull PageTitle title) { ClipboardUtil.setPlainText(this, null, title.getCanonicalUri()); FeedbackUtil.showMessage(this, R.string.address_copied); } @Override public void onLinkPreviewAddToList(@NonNull PageTitle title) { bottomSheetPresenter.showAddToListDialog(getSupportFragmentManager(), title, AddToReadingListDialog.InvokeSource.LINK_PREVIEW_MENU); } @Override public void onLinkPreviewShareLink(@NonNull PageTitle title) { ShareUtil.shareText(this, title); } void showError(@Nullable Throwable caught, boolean backOnError) { // Force going back on button press if coming from a single-item featured-image gallery, // because re-setting the collection and calling notifyDataSetChanged() fails to compel the // GalleryItemFragment to attempt to reload its image. // TODO: Find a way to remove this workaround if (backOnError) { errorView.setRetryClickListener(new View.OnClickListener() { @Override public void onClick(View v) { onBackPressed(); } }); } errorView.setError(caught); errorView.setVisibility(View.VISIBLE); } /** * Kicks off the activity after the views are initialized in onCreate. */ private void loadGalleryContent() { updateProgressBar(false, true, 0); if (getIntent().hasExtra(EXTRA_FEATURED_IMAGE)) { FeaturedImage featuredImage = GsonUnmarshaller.unmarshal(FeaturedImage.class, getIntent().getStringExtra(EXTRA_FEATURED_IMAGE)); int age = getIntent().getIntExtra(EXTRA_FEATURED_IMAGE_AGE, 0); loadGalleryItemFor(featuredImage, age); } else { fetchGalleryCollection(); } } /** * Retrieve the complete list of media items for the current page. * When retrieved, the list will be passed to the ViewPager, and will become a * scrollable gallery of media. */ private void fetchGalleryCollection() { if (pageTitle == null) { return; } updateProgressBar(true, true, 0); CallbackTask.execute(new CallbackTask.Task<Map<String, ImageInfo>>() { @Override public Map<String, ImageInfo> execute() throws Throwable { return client.request(pageTitle.getWikiSite(), pageTitle, false); } }, new CallbackTask.Callback<Map<String, ImageInfo>>() { @Override public void success(Map<String, ImageInfo> result) { updateProgressBar(false, true, 0); applyGalleryCollection(buildCollection(result)); } @Override public void failure(Throwable caught) { updateProgressBar(false, true, 0); showError(caught, false); } }); } @NonNull private GalleryCollection buildCollection(Map<String, ImageInfo> result) { List<GalleryItem> list = new ArrayList<>(); for (Map.Entry<String, ImageInfo> entry : result.entrySet()) { if (GalleryCollection.shouldIncludeImage(entry.getValue())) { list.add(new GalleryItem(entry.getKey(), entry.getValue())); } } return new GalleryCollection(list); } /** * Apply a complete collection of media to our scrollable gallery. * @param collection GalleryCollection to apply to the ViewPager. */ private void applyGalleryCollection(@NonNull GalleryCollection collection) { // remove the page transformer while we operate on the pager... galleryPager.setPageTransformer(false, null); // first, verify that the collection contains the item that the user // initially requested, if we have one... int initialImagePos = -1; if (initialFilename != null) { for (GalleryItem item : collection.getItemList()) { if (addUnderscores(item.getName()).equals(addUnderscores(initialFilename))) { initialImagePos = collection.getItemList().indexOf(item); break; } } if (initialImagePos == -1) { // the requested image is not present in the gallery collection, so // add it manually. // (this can happen if the user clicked on an SVG file, since we hide SVGs // by default in the gallery) initialImagePos = 0; collection.getItemList().add(initialImagePos, new GalleryItem(initialFilename)); } } // pass the collection to the adapter! galleryAdapter.setCollection(collection); if (initialImagePos != -1) { // if we have a target image to jump to, then do it! galleryPager.setCurrentItem(initialImagePos, false); } else if (initialImageIndex >= 0 && initialImageIndex < galleryAdapter.getCount()) { // if we have a target image index to jump to, then do it! galleryPager.setCurrentItem(initialImageIndex, false); } galleryPager.setPageTransformer(false, new GalleryPagerTransformer()); } private GalleryItem getCurrentItem() { if (galleryAdapter.getItem(galleryPager.getCurrentItem()) == null) { return null; } return ((GalleryItemFragment) galleryAdapter.getItem(galleryPager.getCurrentItem())).getGalleryItem(); } /** * Populate the description and license text fields with data from the current gallery item. */ public void layOutGalleryDescription() { GalleryItem item = getCurrentItem(); if (item == null) { infoContainer.setVisibility(View.GONE); return; } galleryAdapter.notifyFragments(galleryPager.getCurrentItem()); CharSequence descriptionStr = ""; if (item.getMetadata() != null && item.getMetadata().imageDescription() != null) { descriptionStr = StringUtil.fromHtml(item.getMetadata().imageDescription().value()); } else if (item.getMetadata() != null && item.getMetadata().objectName() != null) { descriptionStr = StringUtil.fromHtml(item.getMetadata().objectName().value()); } if (descriptionStr.length() > 0) { descriptionText.setText(strip(descriptionStr)); descriptionText.setVisibility(View.VISIBLE); } else { descriptionText.setVisibility(View.GONE); } // determine which icon to display... licenseIcon.setImageResource(getLicenseIcon(item)); // Set the icon's content description to the UsageTerms property. // (if UsageTerms is not present, then default to Fair Use) String usageTerms = (item.getMetadata() == null || item.getMetadata().usageTerms() == null) ? null : item.getMetadata().usageTerms().value(); if (TextUtils.isEmpty(usageTerms)) { usageTerms = getString(R.string.gallery_fair_use_license); } licenseIcon.setContentDescription(usageTerms); // Give the license URL to the icon, to be received by the click handler (may be null). licenseIcon.setTag(item.getLicenseUrl()); String creditStr = ""; if (item.getMetadata() != null && item.getMetadata().artist() != null) { // todo: is it intentional to convert to a String? creditStr = StringUtil.fromHtml(item.getMetadata().artist().value()).toString().trim(); } // if we couldn't find a attribution string, then default to unknown if (TextUtils.isEmpty(creditStr)) { creditStr = getString(R.string.gallery_uploader_unknown); } creditText.setText(creditStr); infoContainer.setVisibility(View.VISIBLE); } /** * Return an icon (drawable resource id) that corresponds to the type of license * under which the specified Gallery item is provided. * @param item Gallery item for which to give a license icon. * @return Resource ID of the icon to display, or 0 if no license is available. */ private static int getLicenseIcon(GalleryItem item) { return item.getLicense().getLicenseIcon(); } private void setBackgroundGradient(View view, int gravity) { view.setBackground(GradientUtil.getPowerGradient(R.color.black54, gravity)); } private void initToolbar() { final Toolbar toolbar = findViewById(R.id.gallery_toolbar); setBackgroundGradient(toolbar, Gravity.TOP); setSupportActionBar(toolbar); getSupportActionBar().setDisplayHomeAsUpEnabled(true); getSupportActionBar().setTitle(""); } /** * Adapter that will provide the contents for the ViewPager. * Each media item will be represented by a GalleryItemFragment, which will be instantiated * lazily, and then cached for future use. */ private class GalleryItemAdapter extends FragmentPagerAdapter { private GalleryCollection galleryCollection; private SparseArray<GalleryItemFragment> fragmentArray; GalleryItemAdapter(AppCompatActivity activity) { super(activity.getSupportFragmentManager()); fragmentArray = new SparseArray<>(); } public void setCollection(@NonNull GalleryCollection collection) { galleryCollection = collection; notifyDataSetChanged(); } public void notifyFragments(int currentPosition) { for (int i = 0; i < getCount(); i++) { if (fragmentArray.get(i) != null) { fragmentArray.get(i).onUpdatePosition(i, currentPosition); } } } /** * Remove any active fragments to the left+1 and right+1 of the current * fragment, to reduce memory usage. */ public void purgeFragments(boolean removeAll) { int position = galleryPager.getCurrentItem(); FragmentTransaction trans = getSupportFragmentManager().beginTransaction(); for (int i = 0; i < getCount(); i++) { if (!removeAll && Math.abs(position - i) < 2) { continue; } if (fragmentArray.get(i) != null) { trans.remove(fragmentArray.get(i)); fragmentArray.remove(i); fragmentArray.put(i, null); } } trans.commitAllowingStateLoss(); } @Override public int getCount() { return galleryCollection == null ? 0 : galleryCollection.getItemList().size(); } @Override public Fragment getItem(int position) { if (galleryCollection == null || galleryCollection.getItemList().size() <= position) { return null; } // instantiate a new fragment if it doesn't exist if (fragmentArray.get(position) == null) { fragmentArray.put(position, GalleryItemFragment.newInstance(pageTitle, wiki, galleryCollection.getItemList().get(position))); } return fragmentArray.get(position); } } private class MediaDownloadReceiverCallback implements MediaDownloadReceiver.Callback { @Override public void onSuccess() { FeedbackUtil.showMessage(GalleryActivity.this, R.string.gallery_save_success); } } @ColorInt private int color(@ColorRes int id) { return ContextCompat.getColor(this, id); } }