ImageUrlManager.java

public class ImageUrlManager {

    private static final String HTTP = "http";
    private static final String GIF = ".gif";

    private static final String KEY_IMAGEMOGR2 = "?imageMogr2";

    /**
     * Refer to: https://portal.qiniu.com/myTickets/ticketDetail?id=36037
     * There is one bug in qiniu.com, they may fail to convert gif to
     * animated webp.
     * So they suggested for now, add '/ignore-error/1' flag, if converting
     * failed,
     * The original image will be returned instead of one error msg.
     */
    private static final String ONLY_WEBP = "?imageMogr2/format/webp/ignore-error/1";

    private static int[] sSize = new int[]{1080, 960, 640, 480, 320, 180, 
            160, 80, 60};

    private static SEImageUrlManager sInstance;
    private Map<Integer, String> mCache;

    private SEImageUrlManager() {
        mCache = new HashMap<Integer, String>();
    }

    public synchronized static SEImageUrlManager getInstance() {
        if (sInstance == null) {
            sInstance = new SEImageUrlManager();
        }
        return sInstance;
    }

    public synchronized String getRemoteUrl(String url, int size) {
        if (TextUtils.isEmpty(url)) {
            return url;
        }
        if (!url.startsWith(HTTP)) {
            return url;
        }
        if (url.startsWith(KEY_IMAGEMOGR2)) {
            return url;
        }
        if (url.endsWith(GIF)) {
            return url + ONLY_WEBP;
        }
        if (!mCache.containsKey(size)) {
            String postFix = "";
            for (int i = sSize.length - 1; i >= 0; i--) {
                if (sSize[i] >= size) {
                    // postFix = String.format
                    // ("?imageMogr2/format/webp/thumbnail/%s>", sSize[i]);
                    //
                    // Refer to: https://portal.qiniu
                    // .com/myTickets/ticketDetail?id=36037
                    //
                    // There is one bug in qiniu.com, they may fail to 
                    // convert gif to animated webp.
                    // So they suggested for now, add '/ignore-error/1' flag,
                    // if converting failed,
                    // The original image will be returned instead of one 
                    // error msg.
                    postFix = String.format
                            ("?imageMogr2/format/webp/thumbnail/%s>/ignore" +
                                    "-error/1", sSize[i]);
                    break;
                }
            }
            mCache.put(size, postFix);
        }
        return url + mCache.get(size);
    }
}