计算图片的scale：

public final static int MAX_HEIGHT = 1920;
　　public final static int MAX_WIDTH = 1080;
     * 根据图片的宽高,以定义的MAX_WIDTH和MAX_HEIGHT做参照，计算图片需要缩放的倍数
    private static int calculateInSampleSize(BitmapFactory.Options options) {
        final int imageHeight = options.outHeight;
        final int imageWidth = options.outWidth;
        if(Constant.DEBUG) {
            Log.i(TAG, "==图片的原始width*height: " + imageWidth + " * " + imageHeight);
        if (imageWidth <= MAX_WIDTH && imageHeight <= MAX_HEIGHT) {
            return 1;
        } else {
            double scale = imageWidth >= imageHeight ? imageWidth / MAX_WIDTH : imageHeight / MAX_HEIGHT;
            double log = Math.log(scale) / Math.log(2);
            double logCeil = Math.ceil(log);// 向上舍入
            return (int) Math.pow(2, logCeil);// 2的x数倍，因为图片的缩放处理是以2的整数倍进行的
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图片的裁剪：
private static ByteArrayOutputStream compressJpegImg(Bitmap bmp, String sourceImgPath, int maxSize){
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        bmp = BitmapFactory.decodeFile(sourceImgPath, options);
        int inSampleSize = 1;
        boolean bLongBigBitmap = isLongImg(options.outWidth, options.outHeight);
        if (!bLongBigBitmap) {
            //普通图片
            inSampleSize = calculateInSampleSize(options);
        int quality = 95; // 默认值95，即对所有图片都默认压缩一次，不管原始图片大小，先压缩一次之后再对应处理
        if (inSampleSize > 1) {
             * 对于普通图片压缩比大于2的，第一次的默认质量压缩做大些，防止OOM
             * 经测试10MB的图片inSampleSize= 1， 即仅仅被80%的质量压缩后大概在1.x Mb
            quality = 81;
        BitmapFactory.Options newOptions = new BitmapFactory.Options();
        newOptions.inSampleSize = inSampleSize;
        newOptions.inPreferredConfig = Bitmap.Config.RGB_565;
        bmp = BitmapFactory.decodeFile(sourceImgPath, newOptions);
        try {
            bmp = rotaingImageView(readPictureDegree(sourceImgPath), bmp);
        } catch (Throwable e) {
            System.gc();
            if (Constant.DEBUG) {
                e.printStackTrace();
            try {
                bmp = rotaingImageView(readPictureDegree(sourceImgPath), bmp);
            } catch (Throwable e2) {
                if (Constant.DEBUG) {
                    e2.printStackTrace();
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        bmp.compress(Bitmap.CompressFormat.JPEG, quality, os);
        if(Constant.DEBUG) {
            Log.i(TAG, "==缩放并压缩质量一次后图片大小: " + (os.toByteArray().length / 1024) + "KB, 压缩质量:" + quality + "%, 缩放倍数: " + inSampleSize);
        if (bLongBigBitmap) {
            /** 长图压缩在1MB以内 */
            bmp = compressLongImg(bmp, os, quality);
        } else {
            /** 普通图片压缩在200Kb以内 */
            bmp = compressNormalImg(bmp, os, quality, maxSize);
        return os;
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旋转矫正图片的角度：
public static Bitmap rotaingImageView(int angle, Bitmap bitmap) {
        if(angle == 0){
            return bitmap;
        // 旋转图片 动作
        Matrix matrix = new Matrix();
        matrix.postRotate(angle);
        if(Constant.DEBUG) {
            System.out.println("angle2=" + angle);
        // 创建新的图片
        Bitmap resizedBitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
        return resizedBitmap;
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获取当前图片旋转的角度：
     * 读取图片属性：旋转的角度
     * @param path
     *            图片绝对路径
     * @return degree旋转的角度
    public static int readPictureDegree(String path) {
        int degree = 0;
        try {
            ExifInterface exifInterface = new ExifInterface(path);
            int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
            //Log.i("PhotoView", "=========orientation: " + orientation);
            switch (orientation) {
            case ExifInterface.ORIENTATION_ROTATE_90:
                degree = 90;
                break;
            case ExifInterface.ORIENTATION_ROTATE_180:
                degree = 180;
                break;
            case ExifInterface.ORIENTATION_ROTATE_270:
                degree = 270;
                break;
            default:
                break;
        } catch (IOException e) {
            e.printStackTrace();
        return degree;
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长图片的质量压缩：
/** 长图压缩在1MB以内 */
    private static Bitmap compressLongImg(Bitmap bmp, ByteArrayOutputStream os, int quality){
        if (os.toByteArray().length / 1024 > 5 * 1024) {
            quality = 60;
        int i = 0;
        while (os.toByteArray().length > IMAGE_MAX_SIZE_1MB && i < 20) {
            i++;
            try {
                os.reset();
                quality = quality * 90 / 100;
                if (quality <= 0) {
                    quality = 5;
                // Log.i(TAG, "==长图压缩质量quality: " + quality + "%， 压缩次数： " + (i + 1));
                bmp.compress(Bitmap.CompressFormat.JPEG, quality, os);
            } catch (Exception e) {
        if(Constant.DEBUG) {
            Log.i(TAG, "长图：" + os.toByteArray().length / 1024 + "Kb");    
        return bmp;
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普通静态图片的质量压缩：
/** 普通图片压缩在200Kb以内 */
    private static Bitmap compressNormalImg(Bitmap bmp, ByteArrayOutputStream os, int quality, int maxSize){
        int length = os.toByteArray().length / 1024;
        if (length >= 1000) {
            quality = 20;
        } else if (length >= 300) {
            quality -= (length - 200) / 20 * 0.8;
        if (quality <= 0) {
            quality = 50;
        int i = 0;
        while (os.toByteArray().length > maxSize && i < 20) {
            i++;
            try {
                os.reset();
                quality = quality * 91 / 100;
                if (quality <= 0) {
                    quality = 5;
                if(Constant.DEBUG) {
                    Log.i(TAG, "==普通图片压缩质量quality: " + quality + "%，  压缩次数： " + (i + 1));
                bmp.compress(Bitmap.CompressFormat.JPEG, quality, os);
            } catch (Exception e) {
        if(Constant.DEBUG) {
            Log.i(TAG, "普通：" + os.toByteArray().length / 1024 + "Kb");
        return bmp;
View Code
GIF图片的压缩，其中用到的GifImageDecoder网上找的解析GIF的代码，也可以用Glide自带的GifDecoder，只是需要一个BitmapProvider对象来满足其代理模式。AnimatedGifEncoder来自Glide库：




    

     * 抽帧的方式
     * **/
    private static boolean compressGifImg(String sourceImgPath, File desFile) {
        File sourceFile = new File(sourceImgPath);
        if (sourceFile == null || !sourceFile.exists()) {
            return false;
        if (sourceFile.length() < IMAGE_MAX_SIZE_1MB) {
            return FileUtils.copyFile(sourceImgPath, desFile.getAbsolutePath());
        } else {
            //Toast.makeText(BusOnlineApp.mApp.getApplicationContext(),"Gif图片太大需要压缩",Toast.LENGTH_SHORT).show();
        GifImageDecoder gifImageDecoder = new GifImageDecoder();
        InputStream is = null;
        try {
            is = new FileInputStream(sourceFile);
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        try {
            if(gifImageDecoder.read(is) != GifImageDecoder.STATUS_OK){
                LogUtil.i(TAG, "Gif图片解析失败");
                return false;
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        int step = 1;
        boolean status = false;
        int iCount = gifImageDecoder.getFrameCount();
        ArrayList<GifFrame> listFrams = new ArrayList<GifImageDecoder.GifFrame>();
            listFrams.clear();
            step++;
            for (int i = 0; i < iCount; i += step) {
                listFrams.add(gifImageDecoder.getGifFrames().get(i));
            status = makeGif(desFile, listFrams, step);
            if (status) {
                if(Constant.DEBUG)
                    Log.i(TAG, "Gif图片压缩完成后: " + desFile.length() / 1024 + "KB");
            } else {
                Log.i(TAG, "Gif图片合成失败");
                break;
        } while (desFile.length() > IMAGE_MAX_SIZE_1MB);
        gifImageDecoder.recycle();
        return status;
View Code
GIF抽帧后拼凑：
private static boolean makeGif(File saveFile, ArrayList<GifFrame> gifFrames, int step) {
        AnimatedGifEncoder gifEncoder = new AnimatedGifEncoder();
        if (!saveFile.exists())
            try {
                saveFile.createNewFile();
            } catch (IOException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
　　　　　//为了矫正时间做出的调整
        if (step > 3) {
            step--;
        OutputStream os;
        try {
            os = new FileOutputStream(saveFile);
            gifEncoder.start(os); 
            for (int i = 0; i < gifFrames.size(); i++) {
                gifEncoder.addFrame(gifFrames.get(i).image);
                gifEncoder.setDelay(gifFrames.get(i).delay * step);
                gifEncoder.setRepeat(0);
            return gifEncoder.finish();
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        return false;
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图片压缩处理完成。
二.PhotoView长图预览大图的时候显示效果优化
　　最终效果：类似新浪微博或微信朋友圈。宽度填充整个屏幕，高度可滑动；或宽度滑动，高度占据屏幕的2/3（手机全景图），具体根据显示的View来，我们需要的是填充整个屏幕，所以View是match_parent的。
　　因为用的是PhotoView库，所以在PhotoViewAttacher.class中修改的源码函数private void updateBaseMatrix(Drawable d) ，思路：计算缩放比例，按照当前显示的View尺寸来计算的，代码如下：
     * Calculate Matrix for FIT_CENTER
     * @param d- Drawable being displayed
    private void updateBaseMatrix(Drawable d) {
        ImageView imageView = getImageView();
        if (null == imageView || null == d) {
            return;
        final float viewWidth = getImageViewWidth(imageView);
        final float viewHeight = getImageViewHeight(imageView);
        final int drawableWidth = d.getIntrinsicWidth();
        final int drawableHeight = d.getIntrinsicHeight();
        mBaseMatrix.reset();
        if (isLongImg(drawableWidth, drawableHeight)) {
            final float widthScale = viewWidth / drawableWidth;
            float heightScale = 1f;
            if (drawableWidth > drawableHeight) {
                // 长图类似全景图，高度只占photoview的1/2
                heightScale = viewHeight / (drawableHeight * 2);
            } else {
                heightScale = viewHeight / drawableHeight;
            float scale = Math.max(widthScale, heightScale);
            mBaseMatrix.postScale(scale, scale);
            mBaseMatrix.postTranslate(0f, 0f);
        } else {
            if (mScaleType == ScaleType.CENTER) {
                mBaseMatrix.postTranslate((viewWidth - drawableWidth) / 2F, (viewHeight - drawableHeight) / 2F);
            } else if (mScaleType == ScaleType.CENTER_CROP) {
                final float widthScale = viewWidth / drawableWidth;
                final float heightScale = viewHeight / drawableHeight;
                float scale = Math.max(widthScale, heightScale);
                mBaseMatrix.postScale(scale, scale);
                mBaseMatrix.postTranslate((viewWidth - drawableWidth * scale) / 2F, (viewHeight - drawableHeight * scale) / 2F);
            } else if (mScaleType == ScaleType.CENTER_INSIDE) {
                final float widthScale = viewWidth / drawableWidth;
                final float heightScale = viewHeight / drawableHeight;
                float scale = Math.min(1.0f, Math.min(widthScale, heightScale));
                mBaseMatrix.postScale(scale, scale);
                mBaseMatrix.postTranslate((viewWidth - drawableWidth * scale) / 2F, (viewHeight - drawableHeight * scale) / 2F);
            } else {
                RectF mTempSrc = new RectF(0, 0, drawableWidth, drawableHeight);
                RectF mTempDst = new RectF(0, 0, viewWidth, viewHeight);
                if ((int) mBaseRotation % 180 != 0) {
                    mTempSrc = new RectF(0, 0, drawableHeight, drawableWidth);
                switch (mScaleType) {
                case FIT_CENTER:
                    mBaseMatrix.setRectToRect(mTempSrc, mTempDst, ScaleToFit.CENTER);
                    break;
                case FIT_START:
                    mBaseMatrix.setRectToRect(mTempSrc, mTempDst, ScaleToFit.START);
                    break;
                case FIT_END:
                    mBaseMatrix.setRectToRect(mTempSrc, mTempDst, ScaleToFit.END);
                    break;
                case FIT_XY:
                    mBaseMatrix.setRectToRect(mTempSrc, mTempDst, ScaleToFit.FILL);
                    break;
                default:
                    break;
        resetMatrix();
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三.Glide的一些问题
　　1.从缓存中获取图片作为占位图问题
　　需求：在列表里面显示缩略的小图，当点击小图后显示大图，因为小图已经下载来了，那么在下载大图的时候用小图去占位显示，用户体验效果会好很多。
　　但是Glide是每个size的都是单独缓存的，所以就存在这样的问题，无法用已经下载的小图去占位显示。因为Glide缓存id即存储在内存或本地文件中的文件名是根据图片信息：name（网络图片的url），decoder，encoder，transformation，size等等去用散列算法生成的一个key，所以据我了解就算有了网络图片的url，不知道图片的size等信息是无法拼凑出这个key，从缓存中单独拿出数据的，从而无法实现前面说的先显示缩略图来占位的效果。so，加以改造Glide的源码，在生成小图的缓存key的时候去掉一些信息，只留下name信息（对于要求不管缩略图还是原图的GIF都要动的，此方法不行，我们的效果：列表中显示小缩略图的时候不动就如jpeg，效果参加：新浪微博）。为什么不能全部去掉呢？因为全部去掉对于GIF图片就可能存在不动的情况，因为去掉后，缓存的数据中没有decoder，encoder，transformation等信息，导致可能无法识别成GIF的问题。所以区别对待：缓存小图的时候只用name，缓存原图的时候加上全部信息。具体代码在Glide的EngineKey.class中的函数public void updateDiskCacheKey(MessageDigest messageDigest)，代码如下：
　@Override
    public void updateDiskCacheKey(MessageDigest messageDigest) throws UnsupportedEncodingException {
         * 注释掉其他信息，为了方便获取文件名字，只依照url去生成
        if(bSimple){
            signature.updateDiskCacheKey(messageDigest);
            messageDigest.update(id.getBytes(STRING_CHARSET_NAME));
        }else {
            byte[] dimensions = ByteBuffer.allocate(8)
                    .putInt(width)
                    .putInt(height)
                    .array();
            signature.updateDiskCacheKey(messageDigest);
            messageDigest.update(id.getBytes(STRING_CHARSET_NAME));
            messageDigest.update(dimensions);
            messageDigest.update((cacheDecoder   != null ? cacheDecoder  .getId() : "").getBytes(STRING_CHARSET_NAME));
            messageDigest.update((decoder        != null ? decoder       .getId() : "").getBytes(STRING_CHARSET_NAME));
            messageDigest.update((transformation != null ? transformation.getId() : "").getBytes(STRING_CHARSET_NAME));
            messageDigest.update((encoder        != null ? encoder       .getId() : "").getBytes(STRING_CHARSET_NAME));
            // The Transcoder is not included in the disk cache key because its result is not cached.
            messageDigest.update((sourceEncoder  != null ? sourceEncoder .getId() : "").getBytes(STRING_CHARSET_NAME));
    private static boolean bSimple = true;
    public static void setCacheKeySimple(boolean b){
        bSimple = b;
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2.Glide加载长图问题
因为显示图片的ImageView尺寸在绘制的时候只能是手机屏幕的尺寸，但是Glide的图片在加载或下载图片的时候的尺寸是从传进去的imageView来获取的！Glide.with(mContext).load(path).error(color).into(imageView)
就算利用Glide.with(mContext).load(path).override(Target.SIZE_ORIGINAL, Target.SIZE_ORIGINAL).into(imageView)也无法在源码中会判断imageView的尺寸做矫正的。源码如下：
private int getViewHeightOrParam() {
            final LayoutParams layoutParams = view.getLayoutParams();
            if (isSizeValid(view.getHeight())) {
                return view.getHeight();
            } else if (layoutParams != null) {
                return getSizeForParam(layoutParams.height, true /*isHeight*/);
            } else {
                return PENDING_SIZE;
        private int getViewWidthOrParam() {
            final LayoutParams layoutParams = view.getLayoutParams();
            if (isSizeValid(view.getWidth())) {
                return view.getWidth();
            } else if (layoutParams != null) {
                return getSizeForParam(layoutParams.width, false /*isHeight*/);
            } else {
                return PENDING_SIZE;
所以我们就需要改造下，目前比较笨的方法也如同处理缓存的方式一样，加入个flag判断，如下：
private int getViewHeightOrParam() {
            if(USE_ORIGINAL_SIZE){
                return Target.SIZE_ORIGINAL;
            final LayoutParams layoutParams = view.getLayoutParams();
            if (isSizeValid(view.getHeight())) {
                return view.getHeight();
            } else if (layoutParams != null) {
                return getSizeForParam(layoutParams.height, true /*isHeight*/);
            } else {
                return PENDING_SIZE;
        private int getViewWidthOrParam() {
            if(USE_ORIGINAL_SIZE){
                return Target.SIZE_ORIGINAL;
            final LayoutParams layoutParams = view.getLayoutParams();
            if (isSizeValid(view.getWidth())) {
                return view.getWidth();
            } else if (layoutParams != null) {
                return getSizeForParam(layoutParams.width, false /*isHeight*/);
            } else {
                return PENDING_SIZE;
public static boolean USE_ORIGINAL_SIZE = false;
public static void useOriginalSize(boolean bOriginal){
        USE_ORIGINAL_SIZE = bOriginal;
3.Glide在使用BaseAdapter时候setTag（）问题
　　因为在Glide中调用View的setTag(Object tag)会导致冲突，貌似是Glide中有使用此法，所以我们就调用另外一个imageView.setTag(int key, Object tag); ---对应getTag(int key)， 但是要注意这个key，不能自定义int值，不然会报错：The key must be an application-specific resource id.  我们可以用view的id，比如：
convertView.setTag(R.layout.comm_act_detail_layout, viewHolder);
......
viewHolder = (ViewHolder) convertView.getTag(R.layout.comm_act_detail_layout);
4.GLide图片下载
在子线程中调用下载
public static Bitmap downloadPicByUrl(Context context, String picUrl){
        Bitmap bitmap=null;
        try {
            FutureTarget<Bitmap> futureTarget = Glide.with(context).load(picUrl).asBitmap().into(Target.SIZE_ORIGINAL, Target.SIZE_ORIGINAL);
            bitmap = futureTarget.get();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        return bitmap;
或者用下面的方法得到File
File file = Glide.with(context).load(path).downloadOnly(Target.SIZE_ORIGINAL, Target.SIZE_ORIGINAL).get();