利用android开源库android-gif-drawable加载gif格式图片

在android项目中，最学用的是png格式的图片，或者用jpeg的图片。那我们要用动画类型图片gif格式图片应该怎么办呢？我们可以使用android-gif-drawable框架来实现gif图片加载，下面直接贴下我在项目中用到的工具类：

public class GifLoader {

/**保存图片引用的Map*/

public static Map<ImageView, String> mImageViewMap = Collections.synchronizedMap(new HashMap<ImageView, String>());

private ExecutorService executorService;

/**缓存大小10MiB*/

private static int mMemCacheMaxSize = 10 * 1024 * 1024;

/**LruCache缓存图片*/

private static LruCache<String, byte[]> mMemLruCache;

/**版本号*/

private static int mAppVersion = 1;

/**硬盘缓存50M*/

private static int mDiskCacheMaxSize = 50 * 1024 * 1024;

/**硬盘缓存对象*/

private static DiskLruCache mDiskLruCache;

/**是否要初始化*/

private static boolean mCacheInit = false;

private static final int DISK_CACHE_COUNT = 1;

/**GifLoader对象*/

private static GifLoader loader;

/**默认一张图片的id*/

final int default_image_id = R.drawable.icon_app_normal;

/**构造对象*/

private GifLoader(Context context) {

executorService = Executors.newFixedThreadPool(2);

initCaches(context);

}

/**单例模式*/

public synchronized static GifLoader getInstance(Context context) {

if (loader == null) {

loader = new GifLoader(context);

}

return loader;

}

/**在控件上展示图片*/

public void displayImage(String url, GifImageView imageView, boolean isGif) {

try {

if (new File(url).exists()) {

imageView.setImageDrawable(new GifDrawable(url));

return;

}

}

catch (Exception e) {

}

mImageViewMap.put(imageView, url);

byte[] data = mMemLruCache.get(url);

if (data != null) {

try {

imageView.setImageDrawable(new GifDrawable(data));

}

catch (Exception e) {

e.printStackTrace();

imageView.setImageResource(default_image_id);

}

}

else {

queuePhoto(url, imageView);

imageView.setImageResource(default_image_id);

}

}

private void queuePhoto(String url, GifImageView imageView) {

PhotoToLoad photoToLoad = new PhotoToLoad(url, imageView);

executorService.submit(new PhotosLoader(photoToLoad));

}

/**此方法待优化以防止内存溢出 先从文件里面读取，没有的话再到网上下载*/

private byte[] getBitmap(String url) {

Snapshot cacheEntry = null;

try {

cacheEntry = mDiskLruCache.get(CacheHelper.UriToDiskLruCacheString(url));

}

catch (Exception e) {

e.printStackTrace();

}

byte[] image = null;

if (cacheEntry != null) {

image = inputStreamToByteArray(cacheEntry.getInputStream(0), (int) cacheEntry.getLength(0));

mMemLruCache.put(url, image);

}

try {

if (image != null) {

return image;

}

else {

URL imageUrl = new URL(url);

HttpURLConnection con = (HttpURLConnection) imageUrl.openConnection();

con.setConnectTimeout(30000);

con.setReadTimeout(30000);

con.setInstanceFollowRedirects(true);

InputStream is = con.getInputStream();

image = inputStreamToByteArray(is, 8096);

if (image != null) {

try {

Editor editor = mDiskLruCache.edit(CacheHelper.UriToDiskLruCacheString(url));

if (editor != null) {

if (CacheHelper.writeByteArrayToEditor(image, editor)) {

mDiskLruCache.flush();

editor.commit();

}

else {

editor.abort();

}

}

}

catch (Exception e) {

e.printStackTrace();

}

mMemLruCache.put(url, image);

}

}

}

catch (FileNotFoundException e) {

e.printStackTrace();

}

catch (MalformedURLException e) {

e.printStackTrace();

}

catch (IOException e) {

e.printStackTrace();

}

return image;

}

private class PhotosLoader implements Runnable {

private PhotoToLoad photoToLoad;

public PhotosLoader(PhotoToLoad photoToLoad) {

super();

this.photoToLoad = photoToLoad;

}

@Override

public void run() {

/**下载前检查imageview是否被复用*/

if (imageViewReused(photoToLoad)) { return; }

byte[] bm = getBitmap(photoToLoad.url);

/**下载完毕后再次检查imageview是否被复用*/

if (imageViewReused(photoToLoad)) { return; }

DisplayImageRunnable displayImageRunnable = new DisplayImageRunnable(bm, photoToLoad);

Activity a = (Activity) photoToLoad.imageView.getContext();

a.runOnUiThread(displayImageRunnable);

}

}

boolean imageViewReused(PhotoToLoad photoToLoad) {

String tag = mImageViewMap.get(photoToLoad.imageView);

/**代表imageviews map中存放的imageview对应的value值已经被覆盖掉，也就是重用了*/

if (tag == null || !tag.equals(photoToLoad.url)) {

return true;

}

else {

return false;

}

}

private class DisplayImageRunnable implements Runnable {

private byte[] data;

private PhotoToLoad photoToLoad;

public DisplayImageRunnable(byte[] data, PhotoToLoad photoToLoad) {

super();

this.data = data;

this.photoToLoad = photoToLoad;

}

@Override

public void run() {

if (imageViewReused(photoToLoad)) { return; }

if (data != null) {

try {

photoToLoad.imageView.setImageDrawable(new GifDrawable(data));

}

catch (Exception e) {

e.printStackTrace();

photoToLoad.imageView.setImageResource(default_image_id);

}

}

else {

photoToLoad.imageView.setImageResource(default_image_id);

}

}

}

private class PhotoToLoad {

public String url;

public GifImageView imageView;

public PhotoToLoad(String url, GifImageView imageView) {

super();

this.url = url;

this.imageView = imageView;

}

}

private void initCaches(Context context) {

if (!mCacheInit) {

mMemLruCache = new LruCache<String, byte[]>(mMemCacheMaxSize) {

protected int sizeOf(String key, byte[] value) {

return value.length;

}

};

File diskCacheDir = CacheHelper.getDiskCacheDir(context, "imagecache");

try {

mDiskLruCache = DiskLruCache.open(diskCacheDir, mAppVersion, DISK_CACHE_COUNT, mDiskCacheMaxSize);

}

catch (IOException ignored) {

}

mCacheInit = true;

}

}

private byte[] inputStreamToByteArray(InputStream is, int size) {

ByteArrayOutputStream byteBuffer = new ByteArrayOutputStream();

byte[] buffer = new byte[size];

int len = 0;

try {

while ((len = is.read(buffer)) != -1) {

byteBuffer.write(buffer, 0, len);

}

}

catch (IOException e) {

e.printStackTrace();

}

buffer = byteBuffer.toByteArray();

return buffer;

}

}