android Bitmap、Drawable、byte[]相互转换

<wbr><wbr><wbr><wbr>Drawable -作为Android平下通用的图形对象，它可以装载常用格式的图像，比如GIF、PNG、JPG，当然也支持BMP，当然还提供一些高级的可视化对象，比如渐变、图形等。 <p><wbr><wbr><wbr><wbr>Bitmap -称作位图，一般位图的文件格式后缀为bmp，当然编码器也有很多如RGB565、RGB888。作为一种像素的显示对象执行效率高，但是缺点也很明显存储效率低。我们理解为一种存储对象比较好。</wbr></wbr></wbr></wbr></p> <p><wbr>android在处理一写图片资源的时候，会进行一些类型的转换，现在有空整理一下：<br><br> 1、Drawable → Bitmap 的简单方法<wbr></wbr></wbr></p> <p><strong>Drawable d = XXX;</strong></p> <p><strong>BitmapDrawable<wbr> bd =(BitmapDrawable)d;</wbr></strong></p> <p><strong>Bitmap<wbr> b =bd.getBitmap();</wbr></strong></p> <p>可简化为：((BitmapDrawable)res.getDrawable(R.drawable.youricon)).getBitmap();<br></p> <wbr><br> Java代码<br> public static Bitmap drawableToBitmap(Drawable drawable){<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr>Bitmap bitmap= Bitmap<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>.createBitmap(<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>drawable.getIntrinsicWidth(),<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>drawable.getIntrinsicHeight(),<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>drawable.getOpacity() != PixelFormat.OPAQUE ?Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565);<wbr>//按指定参数创建一个空的Bitmap对象<br><wbr><wbr><wbr><wbr><wbr><wbr>Canvas canvas= new Canvas(bitmap);<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr>//canvas.setBitmap(bitmap);<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr>drawable.setBounds(0,0, drawable.getIntrinsicWidth(),drawable.getIntrinsicHeight());<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr>drawable.draw(canvas);<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr>returnbitmap;<wbr><wbr><br> }<wbr><wbr><br><br><br> 3.Bitmap→Drawable<wbr><wbr>的简单方法<br><strong style="font-weight:normal">BitmapDrawable bitmapDrawable= (BitmapDrawable)bitmap;<wbr><wbr><wbr><wbr><br> Drawable drawable = (Drawable)bitmapDrawable;<wbr><wbr></wbr></wbr></wbr></wbr></wbr></wbr></strong><wbr><wbr><br><wbr><wbr><wbr><br><strong><span style="font-weight:normal">Bitmap bitmap = newBitmap (...);<wbr><wbr><wbr><wbr></wbr></wbr></wbr></wbr></span><br style="font-weight:normal"> Drawable drawable = new BitmapDrawable(bitmap);<wbr><wbr><br></wbr></wbr></strong><br><br> 3、从资源中获取Bitmap<br> Java代码<br> Bitmap bmp=BitmapFactory.decodeResource(getResources(),R.drawable.pic);<wbr><wbr><br><br> 4、Bitmap → Byte[]<br> Java代码<br> private byte[] Bitmap2Bytes(Bitmapbm){<wbr><wbr><br><wbr><wbr> ByteArrayOutputStream baos =new ByteArrayOutputStream();<wbr><br><wbr><wbr>bm.compress(Bitmap.CompressFormat.PNG, 100, baos);<br><wbr><wbr> returnbaos.toByteArray();<wbr><wbr><br> }<wbr><wbr><br><br> 5、 byte[] → Bitmap<br> Java代码<br> private Bitmap Bytes2Bimap(byte[]b){<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>if(b.length!=0){<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr> returnBitmapFactory.decodeByteArray(b, 0,b.length);<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>}<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>else{<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr> returnnull;<wbr><wbr><br><wbr><wbr><wbr><wbr><wbr><wbr><wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>