//進(jìn)行大小縮放來達(dá)到壓縮的目的 BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeFile(srcImagePath, options); //根據(jù)原始圖片的寬高比和期望的輸出圖片的寬高比計(jì)算最終輸出的圖片的寬和高 float srcWidth = options.outWidth; float srcHeight = options.outHeight; float maxWidth = outWidth; float maxHeight = outHeight; float srcRatio = srcWidth / srcHeight; //原始圖片寬高比 float outRatio = maxWidth / maxHeight; //目標(biāo)圖片寬高比 float actualOutWidth = srcWidth; float actualOutHeight = srcHeight;  if (srcWidth > maxWidth || srcHeight > maxHeight) {   if(srcRatio>outRatio){ //原始寬高比大于目標(biāo)寬高比     actualOutWidth = maxWidth;     actualOutHeight = actualOutWidth / srcRatio;   }else if(srcRatio<outRatio){ //原始寬高比小于目標(biāo)寬高比     actualOutHeight = maxHeight;     actualOutWidth = actualOutHeight * srcRatio;   } }else{   actualOutWidth = maxWidth;   actualOutHeight = maxHeight; } options.inSampleSize = computSampleSize(options, actualOutWidth, actualOutHeight); options.inJustDecodeBounds = false; Bitmap scaledBitmap = null; try {   scaledBitmap = BitmapFactory.decodeFile(srcImagePath, options); } catch (OutOfMemoryError e) {   e.printStackTrace(); } if (scaledBitmap == null) {   return null; }  //生成最終輸出的bitmap Bitmap actualOutBitmap = Bitmap.createScaledBitmap(scaledBitmap, (int) actualOutWidth, (int) actualOutHeight, true); //釋放原始位圖資源 if(scaledBitmap!=actualOutBitmap){ //判斷目標(biāo)位圖是否和原始位圖指向棧目標(biāo)相同   scaledBitmap.recycle();   scaledBitmap = null; }  //處理圖片旋轉(zhuǎn)問題 ExifInterface exif = null; try {   exif = new ExifInterface(srcImagePath);   int orientation = exif.getAttributeInt(       ExifInterface.TAG_ORIENTATION, 0);   Matrix matrix = new Matrix();   if (orientation == ExifInterface.ORIENTATION_ROTATE_90) {     matrix.postRotate(90);   } else if (orientation == ExifInterface.ORIENTATION_ROTATE_180) {     matrix.postRotate(180);   } else if (orientation == ExifInterface.ORIENTATION_ROTATE_270) {     matrix.postRotate(270);   }   actualOutBitmap = Bitmap.createBitmap(actualOutBitmap, 0, 0,       actualOutBitmap.getWidth(), actualOutBitmap.getHeight(), matrix, true); } catch (IOException e) {   e.printStackTrace();   return null; }  //進(jìn)行有損壓縮 ByteArrayOutputStream baos = new ByteArrayOutputStream(); int options_ = 100; actualOutBitmap.compress(Bitmap.CompressFormat.JPEG, options_, baos);//質(zhì)量壓縮方法，把壓縮后的數(shù)據(jù)存放到baos中 (100表示不壓縮，0表示壓縮到最小) int baosLength = baos.toByteArray().length; while (baosLength / 1024 > maxFileSize) {//循環(huán)判斷如果壓縮后圖片是否大于maxMemmorrySize,大于繼續(xù)壓縮   baos.reset();//重置baos即讓下一次的寫入覆蓋之前的內(nèi)容   options_ = Math.max(0, options_ - 10);//圖片質(zhì)量每次減少10   actualOutBitmap.compress(Bitmap.CompressFormat.JPEG, options_, baos);//將壓縮后的圖片保存到baos中   baosLength = baos.toByteArray().length;   if (options_ == 0)//如果圖片的質(zhì)量已降到最低則，不再進(jìn)行壓縮     break; } actualOutBitmap.recycle(); //將bitmap保存到指定路徑 FileOutputStream fos = null; String filePath = getOutputFileName(srcImagePath); try {   fos = new FileOutputStream(filePath);   //包裝緩沖流,提高寫入速度   BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(fos);   bufferedOutputStream.write(baos.toByteArray());   bufferedOutputStream.flush(); } catch (FileNotFoundException e) {   return null; } catch (IOException e) {   return null; } finally {   if (baos != null) {     try {       baos.close();     } catch (IOException e) {       e.printStackTrace();     }   }   if (fos != null) {     try {       fos.close();     } catch (IOException e) {       e.printStackTrace();     }   } } //獲取位圖縮放比例 private int computSampleSize(BitmapFactory.Options options, float reqWidth, float reqHeight) {   float srcWidth = options.outWidth;//20   float srcHeight = options.outHeight;//10   int sampleSize = 1;   if (srcWidth > reqWidth || srcHeight > reqHeight) {     int withRatio = Math.round(srcWidth / reqWidth);     int heightRatio = Math.round(srcHeight / reqHeight);     sampleSize = Math.min(withRatio, heightRatio);   }   return sampleSize; }

float srcWidth = options.outWidth;float srcHeight = options.outHeight;float widthScale = outWidth / srcWidth;//目標(biāo)/原始 寬比例float heightScale = outHeight / srcHeight; //目標(biāo)原始 高比//對(duì)比寬高比選擇較大的一種比例float scale = widthScale > heightScale ? widthScale : heightScale;float actualOutWidth = srcWidth;float actualOutHeight = srcHeight;if (scale < 1) {  actualOutWidth = srcWidth * scale;  actualOutHeight = srcHeight * scale;}

  Matrix matrix1 = new Matrix();  matrix1.postScale(scale, scale);// 放大縮小比例  //生成最終輸出的bitmap  Bitmap actualOutBitmap = Bitmap.createBitmap(scaledBitmap, 0, 0, scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix1, true);  if (actualOutBitmap != scaledBitmap) {    scaledBitmap.recycle();    scaledBitmap = null;    System.gc();  }