ImageLoader.java

/*
 * Copyright (C) 2012 YIXIA.COM
 *
 * 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.yixia.zi.loader;

import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;

import android.app.Activity;
import android.graphics.Bitmap;
import android.widget.ImageView;

public abstract class ImageLoader<T> {
	private AtomicBoolean mStopped = new AtomicBoolean(Boolean.FALSE);
	private ThreadPoolExecutor mQueue;
	private MemoryCache<T> mCacheBitmap = new MemoryCache<T>();

	public ImageLoader() {
		mQueue = new ThreadPoolExecutor(10, 10, 60, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>(), sThreadFactory);
		mQueue.allowCoreThreadTimeOut(true);
	}

	public abstract Bitmap getBitmap(final T id);

	public void displayImage(final T id, final Activity activity, final ImageView imageView) {
		Bitmap bitmap = mCacheBitmap.get(id);
		if (bitmap != null) {
			imageView.setImageBitmap(bitmap);
		} else {
			imageView.setTag(id);
			mQueue.execute(new Runnable() {

				@Override
				public void run() {
					final Bitmap bitmap = getBitmap(id);
					if (bitmap != null && !bitmap.isRecycled()) {
						mCacheBitmap.put(id, bitmap);
						Object tag = imageView.getTag();
						if (tag.equals(id)) {
							if (activity != null) {
								activity.runOnUiThread(new Runnable() {
									@Override
									public void run() {
										imageView.setImageBitmap(bitmap);
									}
								});
							}
						}
					}
				}
			});
		}
	}

	public void stopThread() {
		if (!mStopped.get()) {
			mQueue.shutdownNow();
			mCacheBitmap.clear();
			mStopped.set(Boolean.TRUE);
		}
	}

	private static final ThreadFactory sThreadFactory = new ThreadFactory() {
		private final AtomicInteger mCount = new AtomicInteger(1);

		@Override
		public Thread newThread(Runnable r) {
			return new Thread(r, "ImageLoader #" + mCount.getAndIncrement());
		}
	};
}