Java tutorial
/* * Firetweet - Twitter client for Android * * Copyright (C) 2012-2015 Mariotaku Lee <mariotaku.lee@gmail.com> * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package org.getlantern.firetweet.loader.support; import android.content.ContentResolver; import android.content.Context; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.BitmapFactory.Options; import android.net.Uri; import android.os.Handler; import android.support.v4.content.AsyncTaskLoader; import android.util.DisplayMetrics; import com.nostra13.universalimageloader.cache.disc.DiskCache; import com.nostra13.universalimageloader.core.download.ImageDownloader; import com.nostra13.universalimageloader.utils.IoUtils; import org.getlantern.firetweet.app.FiretweetApplication; import org.getlantern.firetweet.util.BitmapUtils; import org.getlantern.firetweet.util.Exif; import org.getlantern.firetweet.util.ImageValidator; import org.getlantern.firetweet.util.imageloader.AccountExtra; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; public class TileImageLoader extends AsyncTaskLoader<TileImageLoader.Result> { private final Uri mUri; private final Handler mHandler; private final DownloadListener mListener; private final ImageDownloader mDownloader; private final DiskCache mDiskCache; private final float mFallbackSize; private final long mAccountId; public TileImageLoader(final Context context, final DownloadListener listener, final long accountId, final Uri uri) { super(context); mHandler = new Handler(); mAccountId = accountId; mUri = uri; mListener = listener; final FiretweetApplication app = FiretweetApplication.getInstance(context); mDownloader = app.getFullImageDownloader(); mDiskCache = app.getFullDiskCache(); final Resources res = context.getResources(); final DisplayMetrics dm = res.getDisplayMetrics(); mFallbackSize = Math.max(dm.heightPixels, dm.widthPixels); } @Override public TileImageLoader.Result loadInBackground() { if (mUri == null) { return Result.nullInstance(); } final String scheme = mUri.getScheme(); if ("http".equals(scheme) || "https".equals(scheme)) { final String url = mUri.toString(); if (url == null) return Result.nullInstance(); final File cacheFile = mDiskCache.get(url); if (cacheFile != null) { final File cacheDir = cacheFile.getParentFile(); if (cacheDir != null && !cacheDir.exists()) { cacheDir.mkdirs(); } } else return Result.nullInstance(); try { // from SD cache final int cachedValidity = ImageValidator.checkImageValidity(cacheFile); if (ImageValidator.isValid(cachedValidity)) { // The file is corrupted, so we remove it from // cache. return decodeBitmapOnly(cacheFile, ImageValidator.isValidForRegionDecoder(cachedValidity)); } final InputStream is = mDownloader.getStream(url, new AccountExtra(mAccountId)); if (is == null) return Result.nullInstance(); final long length = is.available(); mHandler.post(new DownloadStartRunnable(this, mListener, length)); final OutputStream os = new FileOutputStream(cacheFile); try { dump(is, os); mHandler.post(new DownloadFinishRunnable(this, mListener)); } finally { IoUtils.closeSilently(is); IoUtils.closeSilently(os); } final int downloadedValidity = ImageValidator.checkImageValidity(cacheFile); if (ImageValidator.isValid(downloadedValidity)) { // The file is corrupted, so we remove it from // cache. return decodeBitmapOnly(cacheFile, ImageValidator.isValidForRegionDecoder(downloadedValidity)); } else { cacheFile.delete(); throw new IOException(); } } catch (final Exception e) { mHandler.post(new DownloadErrorRunnable(this, mListener, e)); return Result.getInstance(cacheFile, e); } } else if (ContentResolver.SCHEME_FILE.equals(scheme)) { final File file = new File(mUri.getPath()); try { return decodeBitmapOnly(file, ImageValidator.isValidForRegionDecoder(ImageValidator.checkImageValidity(file))); } catch (final Exception e) { return Result.getInstance(file, e); } } return Result.nullInstance(); } protected Result decodeBitmapOnly(final File file, boolean useDecoder) { final String path = file.getAbsolutePath(); final BitmapFactory.Options o = new BitmapFactory.Options(); o.inJustDecodeBounds = true; BitmapFactory.decodeFile(path, o); final int width = o.outWidth, height = o.outHeight; if (width <= 0 || height <= 0) return Result.getInstance(file, null); o.inJustDecodeBounds = false; o.inSampleSize = BitmapUtils.computeSampleSize(mFallbackSize / Math.max(width, height)); final Bitmap bitmap = BitmapFactory.decodeFile(path, o); return Result.getInstance(useDecoder, bitmap, o, Exif.getOrientation(file), file); } @Override protected void onStartLoading() { forceLoad(); } private void dump(final InputStream is, final OutputStream os) throws IOException { final byte buffer[] = new byte[1024]; int rc = is.read(buffer, 0, buffer.length); long downloaded = 0; while (rc > 0) { downloaded += rc; mHandler.post(new ProgressUpdateRunnable(mListener, downloaded)); os.write(buffer, 0, rc); rc = is.read(buffer, 0, buffer.length); } } public static interface DownloadListener { void onDownloadError(Throwable t); void onDownloadFinished(); void onDownloadStart(long total); void onProgressUpdate(long downloaded); } public static class Result { public final Bitmap bitmap; public final Options options; public final File file; public final Exception exception; public final boolean useDecoder; public final int orientation; public Result(final boolean useDecoder, final Bitmap bitmap, final Options options, final int orientation, final File file, final Exception exception) { this.bitmap = bitmap; this.options = options; this.file = file; this.useDecoder = useDecoder; this.orientation = orientation; this.exception = exception; } public boolean hasData() { return bitmap != null || useDecoder; } public static Result getInstance(final Bitmap bitmap, final Options options, final int orientation, final File file) { return new Result(false, bitmap, options, orientation, file, null); } public static Result getInstance(final boolean useDecoder, final Bitmap bitmap, final Options options, final int orientation, final File file) { return new Result(useDecoder, bitmap, options, orientation, file, null); } public static Result getInstance(final File file, final Exception e) { return new Result(false, null, null, 0, file, e); } public static Result nullInstance() { return new Result(false, null, null, 0, null, null); } } private final static class DownloadErrorRunnable implements Runnable { private final TileImageLoader loader; private final DownloadListener listener; private final Throwable t; DownloadErrorRunnable(final TileImageLoader loader, final DownloadListener listener, final Throwable t) { this.loader = loader; this.listener = listener; this.t = t; } @Override public void run() { if (listener == null || loader.isAbandoned() || loader.isReset()) return; listener.onDownloadError(t); } } private final static class DownloadFinishRunnable implements Runnable { private final TileImageLoader loader; private final DownloadListener listener; DownloadFinishRunnable(final TileImageLoader loader, final DownloadListener listener) { this.loader = loader; this.listener = listener; } @Override public void run() { if (listener == null || loader.isAbandoned() || loader.isReset()) return; listener.onDownloadFinished(); } } private final static class DownloadStartRunnable implements Runnable { private final TileImageLoader loader; private final DownloadListener listener; private final long total; DownloadStartRunnable(final TileImageLoader loader, final DownloadListener listener, final long total) { this.loader = loader; this.listener = listener; this.total = total; } @Override public void run() { if (listener == null || loader.isAbandoned() || loader.isReset()) return; listener.onDownloadStart(total); } } private final static class ProgressUpdateRunnable implements Runnable { private final DownloadListener listener; private final long current; ProgressUpdateRunnable(final DownloadListener listener, final long current) { this.listener = listener; this.current = current; } @Override public void run() { if (listener == null) return; listener.onProgressUpdate(current); } } }