Android Bitmap用法大全，以後再也不擔心了

1、Drawable → Bitmap

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public static Bitmap drawableToBitmap(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;   }

2、從資源中獲取Bitmap

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Resources res=getResources();   Bitmap bmp=BitmapFactory.decodeResource(res, R.drawable.pic);

3、Bitmap → byte[]

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private byte[] Bitmap2Bytes(Bitmap bm){   ByteArrayOutputStream baos = new ByteArrayOutputStream();   bm.compress(Bitmap.CompressFormat.PNG, 100, baos);   return baos.toByteArray();   }

4、byte[] → Bitmap

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private Bitmap Bytes2Bimap(byte[] b){   if(b.length!=0){   return BitmapFactory.decodeByteArray(b, 0, b.length);   }   else {   return null;   }   }

5、保存bitmap

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static boolean saveBitmap2file(Bitmap bmp,String filename){   CompressFormat format= Bitmap.CompressFormat.JPEG;   int quality = 100;   OutputStream stream = null;   try {   stream = new FileOutputStream("/sdcard/" + filename);   } catch (FileNotFoundException e) {   // TODO Auto-generated catch block   Generated by Foxit PDF Creator © Foxit Software   http://www.foxitsoftware.com For evaluation only.   e.printStackTrace();   }   return bmp.compress(format, quality, stream);   }

6、將圖片按自己的要求縮放

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// 圖片源   Bitmap bm = BitmapFactory.decodeStream(getResources()   .openRawResource(R.drawable.dog));   // 獲得圖片的寬高   int width = bm.getWidth();   int height = bm.getHeight();   // 設置想要的大小   int newWidth = 320;   int newHeight = 480;   // 計算縮放比例   float scaleWidth = ((float) newWidth) / width;   float scaleHeight = ((float) newHeight) / height;   // 取得想要縮放的matrix參數   Matrix matrix = new Matrix();   matrix.postScale(scaleWidth, scaleHeight);   // 得到新的圖片   Bitmap newbm = Bitmap.createBitmap(bm, 0, 0, width, height, matrix,   true);   // 放在畫布上   canvas.drawBitmap(newbm, 0, 0, paint);

7：File圖片轉Bitmap

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1	Bitmap bt = BitmapFactory.decodeFile("/sdcard/myImage/" + "head.jpg");//圖片地址

8：//圖片轉Bitmap

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public Bitmap drawableToBitamp(int drawableResource) {<span style="white-space:pre">    </span>//可以取raw裏面的資源         BitmapFactory.Options opt = new BitmapFactory.Options();         opt.inPreferredConfig = Bitmap.Config.RGB_565;         opt.inPurgeable = true;         opt.inInputShareable = true;         InputStream is = this.getResources().openRawResource(drawableResource);         BitmapFactory.decodeStream(is, null, opt);         return BitmapFactory.decodeStream(is, null, opt);     }