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Android圖片實(shí)現(xiàn)壓縮處理的實(shí)例代碼

更新時(shí)間：2017年07月27日 09:02:31 作者：MrZang

本篇文章主要介紹了Android圖片實(shí)現(xiàn)壓縮處理的實(shí)例代碼，小編覺(jué)得挺不錯(cuò)的，現(xiàn)在分享給大家，也給大家做個(gè)參考。一起跟隨小編過(guò)來(lái)看看吧

整理文檔，搜刮出一個(gè)Android圖片實(shí)現(xiàn)壓縮處理的實(shí)例代碼，稍微整理精簡(jiǎn)一下做下分享。

詳解:

1.獲取本地圖片F(xiàn)ile文件獲取BitmapFactory.Options對(duì)象計(jì)算原始圖片目標(biāo)圖片寬高比計(jì)算輸出的圖片寬高

2.根據(jù)寬高比計(jì)算options.inSampleSize值（縮放比例 If set to a value > 1, requests the decoder to subsample the original image, returning a smaller image to save memory.）得到bitmap位圖根據(jù)位圖對(duì)象獲取新的輸出位圖對(duì)象 Bitmap.createScaledBitmap(Bitmap src, int dstWidth, int dstHeight, boolean filter)Creates a new bitmap, scaled from an existing bitmap, whenpossible.

3.獲取圖片方向調(diào)整、失量壓縮圖片保持在1024kb以下

 //進(jìn)行大小縮放來(lái)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(wèn)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(xiě)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(xiě)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;
 }

壓縮比例換算：

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;
}

設(shè)置縮放比例--生成新的位圖

  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();
  }

參考：https://github.com/guizhigang/LGImageCompressor

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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