/**
 * 圖片加載及轉(zhuǎn)化工具 ----------------------------------------------------------------------- 延伸：一個(gè)Bitmap到底占用多大內(nèi)存？系統(tǒng)給每個(gè)應(yīng)用程序分配多大內(nèi)存？ Bitmap占用的內(nèi)存為：像素總數(shù)
 * * 每個(gè)像素占用的內(nèi)存。在Android中， Bitmap有四種像素類型：ARGB_8888、ARGB_4444、ARGB_565、ALPHA_8， 他們每個(gè)像素占用的字節(jié)數(shù)分別為4、2、2、1。因此，一個(gè)2000*1000的ARGB_8888
 * 類型的Bitmap占用的內(nèi)存為2000*1000*4=8000000B=8MB。
 * 
 * @author chen.lin
 *
 */
public class BitmapUtil {
 /**
  * 1)軟引用 ,已經(jīng)不適合緩存圖片信息,加載圖片時(shí)會(huì)出現(xiàn)重疊的現(xiàn)象
  * 2)Android 3.0 (API Level 11)中，圖片的數(shù)據(jù)會(huì)存儲(chǔ)在本地的內(nèi)存當(dāng)中
  * 因而無法用一種可預(yù)見的方式將其釋放，這就有潛在的風(fēng)險(xiǎn)造成應(yīng)用程序的內(nèi)存溢出并崩潰，
  * 3)因?yàn)閺?Android 2.3 (API Level 9)開始，垃圾回收器會(huì)更傾向于回收持有軟引用或弱引用的對(duì)象，
   這讓軟引用和弱引用變得不再可靠。
  * 
  */
 private static Map<String, SoftReference<Bitmap>> imageCache = new HashMap<String, SoftReference<Bitmap>>();
 /**
  * 初始化lrucache,最少使用最先移除,LruCache來緩存圖片，
  * 當(dāng)存儲(chǔ)Image的大小大于LruCache設(shè)定的值，系統(tǒng)自動(dòng)釋放內(nèi)存，
  */
 private static LruCache<String, Bitmap> mMemoryCache;
 static {
  final int memory = (int) (Runtime.getRuntime().maxMemory() / 1024);
  final int cacheSize = memory / 8;
  mMemoryCache = new LruCache<String, Bitmap>(cacheSize) {
   protected int sizeOf(String key, Bitmap value) {
    // return value.getByteCount() / 1024;
    return value.getHeight() * value.getRowBytes();
   }
  };
 }
 // ---lrucache----------------------------------------------------
 /**
  * 添加圖片到lrucache
  * 
  * @param key
  * @param bitmap
  */
 public synchronized void addBitmapToMemCache(String key, Bitmap bitmap) {
  if (getBitmapFromMemCache(key) == null) {
   if (key != null & bitmap != null) {
    mMemoryCache.put(key, bitmap);
   }
  }
 }
 /**
  * 清除緩存
  */
 public void clearMemCache() {
  if (mMemoryCache != null) {
   if (mMemoryCache.size() > 0) {
    mMemoryCache.evictAll();
   }
   mMemoryCache = null;
  }
 }
 /**
  * 移除緩存
  */
 public synchronized void removeMemCache(String key) {
  if (key != null) {
   if (mMemoryCache != null) {
    Bitmap bm = mMemoryCache.remove(key);
    if (bm != null)
     bm.recycle();
   }
  }
 }
 /**
  * 從lrucache里讀取圖片
  * 
  * @param key
  * @return
  */
 public Bitmap getBitmapFromMemCache(String key) {
  if (key != null) {
   return mMemoryCache.get(key);
  }
  return null;
 }
 /**
  * 加載圖片
  * 
  * @param context
  * @param resId
  * @param imageView
  */
 public void loadBitmap(Context context, int resId, ImageView imageView) {
  final String imageKey = String.valueOf(resId);
  final Bitmap bitmap = getBitmapFromMemCache(imageKey);
  if (bitmap != null) {
   imageView.setImageBitmap(bitmap);
  } else {
   imageView.setImageResource(resId);
   BitmapWorkerTask task = new BitmapWorkerTask(context);
   task.execute(resId);
  }
 }
 /**
  * 任務(wù)類
  * 
  * @Project App_View
  * @Package com.android.view.tool
  * @author chenlin
  * @version 1.0
  * @Date 2014年5月10日
  */
 class BitmapWorkerTask extends AsyncTask<Integer, Void, Bitmap> {
  private Context mContext;
  public BitmapWorkerTask(Context context) {
   mContext = context;
  }
  // 在后臺(tái)加載圖片。
  @Override
  protected Bitmap doInBackground(Integer... params) {
   final Bitmap bitmap = decodeSampledBitmapFromResource(mContext.getResources(), params[0], 100, 100);
   addBitmapToMemCache(String.valueOf(params[0]), bitmap);
   return bitmap;
  }
 }
 // --軟引用---------------------------------------------------------
 public static void addBitmapToCache(String path) {
  // 強(qiáng)引用的Bitmap對(duì)象
  Bitmap bitmap = BitmapFactory.decodeFile(path);
  // 軟引用的Bitmap對(duì)象
  SoftReference<Bitmap> softBitmap = new SoftReference<Bitmap>(bitmap);
  // 添加該對(duì)象到Map中使其緩存
  imageCache.put(path, softBitmap);
 }
 public static Bitmap getBitmapByPath(String path) {
  // 從緩存中取軟引用的Bitmap對(duì)象
  SoftReference<Bitmap> softBitmap = imageCache.get(path);
  // 判斷是否存在軟引用
  if (softBitmap == null) {
   return null;
  }
  // 取出Bitmap對(duì)象，如果由于內(nèi)存不足Bitmap被回收，將取得空
  Bitmap bitmap = softBitmap.get();
  return bitmap;
 }
 public Bitmap loadBitmap(final String imageUrl, final ImageCallBack imageCallBack) {
  SoftReference<Bitmap> reference = imageCache.get(imageUrl);
  if (reference != null) {
   if (reference.get() != null) {
    return reference.get();
   }
  }
  final Handler handler = new Handler() {
   public void handleMessage(final android.os.Message msg) {
    // 加入到緩存中
    Bitmap bitmap = (Bitmap) msg.obj;
    imageCache.put(imageUrl, new SoftReference<Bitmap>(bitmap));
    if (imageCallBack != null) {
     imageCallBack.getBitmap(bitmap);
    }
   }
  };
  new Thread() {
   public void run() {
    Message message = handler.obtainMessage();
    message.obj = downloadBitmap(imageUrl);
    handler.sendMessage(message);
   }
  }.start();
  return null;
 }
 public interface ImageCallBack {
  void getBitmap(Bitmap bitmap);
 }
 // ----其它工具----------------------------------------------------------------------------------
 /**
  * 從網(wǎng)上下載圖片
  * 
  * @param imageUrl
  * @return
  */
 private Bitmap downloadBitmap(String imageUrl) {
  Bitmap bitmap = null;
  try {
   bitmap = BitmapFactory.decodeStream(new URL(imageUrl).openStream());
   return bitmap;
  } catch (Exception e) {
   e.printStackTrace();
   return null;
  }
 }
 /**
  * drawable 轉(zhuǎn)bitmap
  * 
  * @param drawable
  * @return
  */
 public static Bitmap drawable2Bitmap(Drawable drawable) {
  Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(),
    drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565);
  Canvas canvas = new Canvas(bitmap);
  // canvas.setBitmap(bitmap);
  drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
  drawable.draw(canvas);
  return bitmap;
 }
 /**
  * bitmap 轉(zhuǎn) drawable
  * 
  * @param bm
  * @return
  */
 public static Drawable bitmap2Drable(Bitmap bm) {
  return new BitmapDrawable(bm);
 }
 /**
  * 把字節(jié)數(shù)組通過BASE64Encoder轉(zhuǎn)換成字符串
  * 
  * @param image
  * @return
  */
 public static String getBase64(byte[] image) {
  String string = "";
  try {
   BASE64Encoder encoder = new BASE64Encoder();
   string = encoder.encodeBuffer(image).trim();
  } catch (Exception e) {
   e.printStackTrace();
  }
  return string;
 }
 /**
  * 把字節(jié)數(shù)據(jù)轉(zhuǎn)換成Drawable
  * 
  * @param imgByte
  *   字節(jié)數(shù)據(jù)
  * @return
  */
 @SuppressWarnings("deprecation")
 public static Drawable byte2Drawable(byte[] imgByte) {
  Bitmap bitmap;
  if (imgByte != null) {
   bitmap = BitmapFactory.decodeByteArray(imgByte, 0, imgByte.length);
   Drawable drawable = new BitmapDrawable(bitmap);
   return drawable;
  }
  return null;
 }
 /**
  * 把圖片轉(zhuǎn)換成字節(jié)數(shù)組
  * 
  * @param bmp
  * @return
  */
 public static byte[] bitmap2Byte(Bitmap bm) {
  Bitmap outBitmap = Bitmap.createScaledBitmap(bm, 150, bm.getHeight() * 150 / bm.getWidth(), true);
  if (bm != outBitmap) {
   bm.recycle();
   bm = null;
  }
  byte[] compressData = null;
  ByteArrayOutputStream baos = new ByteArrayOutputStream();
  try {
   try {
    outBitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
   } catch (Exception e) {
    e.printStackTrace();
   }
   compressData = baos.toByteArray();
   baos.close();
  } catch (IOException e) {
   e.printStackTrace();
  }
  return compressData;
 }
 /**
  * 縮放圖片
  * 
  * @param bitmap
  *   原圖片
  * @param newWidth
  * @param newHeight
  * @return
  */
 public static Bitmap setBitmapSize(Bitmap bitmap, int newWidth, int newHeight) {
  int width = bitmap.getWidth();
  int height = bitmap.getHeight();
  float scaleWidth = (newWidth * 1.0f) / width;
  float scaleHeight = (newHeight * 1.0f) / height;
  Matrix matrix = new Matrix();
  matrix.postScale(scaleWidth, scaleHeight);
  return Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
 }
 /**
  * 縮放圖片
  * 
  * @param bitmapPath
  *   圖片路徑
  * @return
  */
 public static Bitmap setBitmapSize(String bitmapPath, float newWidth, float newHeight) {
  Bitmap bitmap = BitmapFactory.decodeFile(bitmapPath);
  if (bitmap == null) {
   Logger.i("bitmap", "bitmap------------>發(fā)生未知異常！");
   return null;
  }
  int width = bitmap.getWidth();
  int height = bitmap.getHeight();
  float scaleWidth = newWidth / width;
  float scaleHeight = newHeight / height;
  Matrix matrix = new Matrix();
  matrix.postScale(scaleWidth, scaleHeight);
  return Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
 }
 /**
  * 計(jì)算圖片的縮放大小 如果==1，表示沒變化，==2，表示寬高都縮小一倍 ----------------------------------------------------------------------------
  * inSampleSize是BitmapFactory.Options類的一個(gè)參數(shù)，該參數(shù)為int型， 他的值指示了在解析圖片為Bitmap時(shí)在長(zhǎng)寬兩個(gè)方向上像素縮小的倍數(shù)。inSampleSize的默認(rèn)值和最小值為1（當(dāng)小于1時(shí)，解碼器將該值當(dāng)做1來處理），
  * 且在大于1時(shí)，該值只能為2的冪（當(dāng)不為2的冪時(shí)，解碼器會(huì)取與該值最接近的2的冪）。 例如，當(dāng)inSampleSize為2時(shí)，一個(gè)2000*1000的圖片，將被縮小為1000*500，相應(yīng)地， 它的像素?cái)?shù)和內(nèi)存占用都被縮小為了原來的1/4：
  * 
  * @param options
  * @param reqWidth
  * @param reqHeight
  * @return
  */
 public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
  // 原始圖片的寬高
  final int height = options.outHeight;
  final int width = options.outWidth;
  int inSampleSize = 1;
  if (height > reqHeight || width > reqWidth) {
   final int halfHeight = height / 2;
   final int halfWidth = width / 2;
   // 在保證解析出的bitmap寬高分別大于目標(biāo)尺寸寬高的前提下，取可能的inSampleSize的最大值
   while ((halfHeight / inSampleSize) > reqHeight && (halfWidth / inSampleSize) > reqWidth) {
    inSampleSize *= 2;
   }
  }
  return inSampleSize;
 }
 /**
  * 根據(jù)計(jì)算出的inSampleSize生成Bitmap(此時(shí)的bitmap是經(jīng)過縮放的圖片)
  * 
  * @param res
  * @param resId
  * @param reqWidth
  * @param reqHeight
  * @return
  */
 public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId, int reqWidth, int reqHeight) {
  // 首先設(shè)置 inJustDecodeBounds=true 來獲取圖片尺寸
  final BitmapFactory.Options options = new BitmapFactory.Options();
  /**
   * inJustDecodeBounds屬性設(shè)置為true，decodeResource()方法就不會(huì)生成Bitmap對(duì)象，而僅僅是讀取該圖片的尺寸和類型信息：
   */
  options.inJustDecodeBounds = true;
  BitmapFactory.decodeResource(res, resId, options);
  // 計(jì)算 inSampleSize 的值
  options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
  // 根據(jù)計(jì)算出的 inSampleSize 來解碼圖片生成Bitmap
  options.inJustDecodeBounds = false;
  return BitmapFactory.decodeResource(res, resId, options);
 }
 /**
  * 將圖片保存到本地時(shí)進(jìn)行壓縮, 即將圖片從Bitmap形式變?yōu)镕ile形式時(shí)進(jìn)行壓縮, 
  * 特點(diǎn)是: File形式的圖片確實(shí)被壓縮了, 但是當(dāng)你重新讀取壓縮后的file為 Bitmap是,它占用的內(nèi)存并沒有改變
  * 
  * @param bmp
  * @param file
  */
 public static void compressBmpToFile(Bitmap bmp, File file) {
  ByteArrayOutputStream baos = new ByteArrayOutputStream();
  int options = 80;// 個(gè)人喜歡從80開始,
  bmp.compress(Bitmap.CompressFormat.JPEG, options, baos);
  while (baos.toByteArray().length / 1024 > 100) {
   baos.reset();
   options -= 10;
   bmp.compress(Bitmap.CompressFormat.JPEG, options, baos);
  }
  try {
   FileOutputStream fos = new FileOutputStream(file);
   fos.write(baos.toByteArray());
   fos.flush();
   fos.close();
  } catch (Exception e) {
   e.printStackTrace();
  }
 }
 /**
  * 將圖片從本地讀到內(nèi)存時(shí),進(jìn)行壓縮 ,即圖片從File形式變?yōu)锽itmap形式
  * 特點(diǎn): 通過設(shè)置采樣率, 減少圖片的像素, 達(dá)到對(duì)內(nèi)存中的Bitmap進(jìn)行壓縮
  * @param srcPath
  * @return
  */
 public static Bitmap compressImageFromFile(String srcPath, float pixWidth, float pixHeight) {
  BitmapFactory.Options options = new BitmapFactory.Options();
  options.inJustDecodeBounds = true;// 只讀邊,不讀內(nèi)容
  Bitmap bitmap = BitmapFactory.decodeFile(srcPath, options);
  options.inJustDecodeBounds = false;
  int w = options.outWidth;
  int h = options.outHeight;
  int scale = 1;
  if (w > h && w > pixWidth) {
   scale = (int) (options.outWidth / pixWidth);
  } else if (w < h && h > pixHeight) {
   scale = (int) (options.outHeight / pixHeight);
  }
  if (scale <= 0)
   scale = 1;
  options.inSampleSize = scale;// 設(shè)置采樣率
  options.inPreferredConfig = Config.ARGB_8888;// 該模式是默認(rèn)的,可不設(shè)
  options.inPurgeable = true;// 同時(shí)設(shè)置才會(huì)有效
  options.inInputShareable = true;// 。當(dāng)系統(tǒng)內(nèi)存不夠時(shí)候圖片自動(dòng)被回收
  bitmap = BitmapFactory.decodeFile(srcPath, options);
  // return compressBmpFromBmp(bitmap);//原來的方法調(diào)用了這個(gè)方法企圖進(jìn)行二次壓縮
  // 其實(shí)是無效的,大家盡管嘗試
  return bitmap;
 }
 /**
  * 判斷照片的角度
  * @param path
  * @return
  */
 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); 
   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; 
   } 
  } catch (IOException e) { 
   e.printStackTrace(); 
  } 
  return degree; 
 } 
 /**
  * Android根據(jù)設(shè)備屏幕尺寸和dpi的不同，給系統(tǒng)分配的單應(yīng)用程序內(nèi)存大小也不同，具體如下表
  * 
  * 屏幕尺寸 DPI 應(yīng)用內(nèi)存 
  * small / normal / large ldpi / mdpi 16MB 
  * small / normal / large tvdpi / hdpi 32MB 
  * small / normal / large xhdpi 64MB
  * small / normal / large 400dpi 96MB 
  * small / normal / large xxhdpi 128MB 
  * ------------------------------------------------------- 
  * xlarge mdpi 32MB 
  * xlarge tvdpi / hdpi 64MB 
  * xlarge xhdpi 128MB 
  * xlarge 400dpi 192MB 
  * xlarge xxhdpi 256MB
  */
}