ImageGetterAsync.java

// LICENSE: USE IT IF YOU NEED IT, BUT PLEASE MENTION AT LEAST MY NAME, THANKS!
// (Juraj Suchán, juraj.suchan@gmail.com)
//
package sk.virtualvoid.nyxdroid.utils;

import java.io.File;
import java.lang.ref.WeakReference;
import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.Executor;

import sk.virtualvoid.android.AsyncTask;
import sk.virtualvoid.android.Log;
import sk.virtualvoid.nyxdroid.R;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.text.Html;
import android.widget.TextView;

/**
 * 
 * @author Juraj
 * 
 */
public class ImageGetterAsync {
	private Context mContext;
	private Resources mResources;
	private Drawable mDefaultDrawable;
	private Executor mExecutor;

	private static final Map<String, WeakReference<Drawable>> mDrawableCache = Collections.synchronizedMap(new WeakHashMap<String, WeakReference<Drawable>>());

	private static final Html.ImageGetter mImageGetterCached = new Html.ImageGetter() {
		public Drawable getDrawable(String source) {
			if (!mDrawableCache.containsKey(source)) {
				return null;
			}
			return mDrawableCache.get(source).get();
		}
	};

	public ImageGetterAsync(Context context, Executor executor) {
		mContext = context;
		mResources = mContext.getResources();

		mDefaultDrawable = mResources.getDrawable(R.drawable.empty_photo);
		mDefaultDrawable.setBounds(0, 0, mDefaultDrawable.getIntrinsicWidth(), mDefaultDrawable.getIntrinsicHeight());

		mExecutor = executor;
	}

	public Html.ImageGetter spawn(String message, TextView textView) {
		final String _message = message;
		final TextView _textView = textView;
		return new Html.ImageGetter() {
			public Drawable getDrawable(String source) {
				if (mDrawableCache.containsKey(source) && mDrawableCache.get(source).get() != null) {
					return mDrawableCache.get(source).get();
				}

				ImageDownloadData imageDownloadData = new ImageDownloadData(_message, _textView, source);
				ImageDownloadAsyncTask imageDownloadTask = new ImageDownloadAsyncTask(imageDownloadData);
				imageDownloadTask.executeOnExecutor(mExecutor, null);
				return mDefaultDrawable;
			}
		};
	}
	
	public static void invalidate() {
		mDrawableCache.clear();
	}

	/**
	 * 
	 * @author Juraj
	 * 
	 */
	class ImageDownloadData {
		private String content;
		private TextView textView;
		private String source;

		public ImageDownloadData(String content, TextView textView, String source) {
			this.content = content;
			this.textView = textView;
			this.source = source;
		}

		public String getContent() {
			return this.content;
		}

		public TextView getTextView() {
			return this.textView;
		}

		public String getSource() {
			return this.source;
		}
	}

	/**
	 * 
	 * @author Juraj
	 * 
	 */
	class ImageDownloadAsyncTask extends AsyncTask<Void, Void, Drawable> {
		private ImageDownloadData imageDownloadData;

		public ImageDownloadAsyncTask(ImageDownloadData imageDownloadData) {
			this.imageDownloadData = imageDownloadData;
		}

		@Override
		protected Drawable doInBackground(Void... params) {
			try {
				File file = U.downloadFileCache(imageDownloadData.getSource());
				if (file == null) {
					file = U.downloadFileWeb(imageDownloadData.getSource());
				}

				if (file == null) {
					return null;
				}

				Bitmap bitmap = U.getBitmapFromFile(file);
				if (bitmap == null) {
					return null;
				}

				Drawable drawable = new BitmapDrawable(mResources, bitmap);
				drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
				return drawable;

			} catch (Throwable t) {
				Log.e("ImageDownloadAsyncTask: " + t.getMessage());
			}
			return null;
		}

		@Override
		protected void onPostExecute(Drawable drawable) {
			if (!mDrawableCache.containsKey(imageDownloadData.getSource())) {
				mDrawableCache.put(imageDownloadData.getSource(), new WeakReference<Drawable>(drawable));
			}
			TextView textView = imageDownloadData.getTextView();
			String content = imageDownloadData.getContent();
			textView.setText(MyHtml.fromHtml(content, mImageGetterCached, null));
		}
	}
}

snip

	private ImageGetterAsync mImageGetter;

	mImageGetter = new ImageGetterAsync(mContext, Executors.newSingleThreadExecutor());

	textView.setText(Html.fromHtml(htmlString, mImageGetter.spawn(htmlString, textView), null));