Android中Bitmap与Drawable、byte[ ]之间的转换

一、Drawable转换成Bitmap
方法一：Drawable drawable = getResources().getDrawable(R.drawable.ic);
BitmapDrawable bd = (BitmapDrawable) drawable;
Bitmap bm= bd.getBitmap();方法二：Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.ic_drawable);方法三：public static Bitmap drawableToBitmap(Drawable drawable) {
// 取 drawable 的长宽
int w = drawable.getIntrinsicWidth();
int h = drawable.getIntrinsicHeight();

// 取 drawable 的颜色格式
Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
: Bitmap.Config.RGB_565;
// 建立对应 bitmap
Bitmap bitmap = Bitmap.createBitmap(w, h, config);
// 建立对应 bitmap 的画布
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, w, h);
// 把 drawable 内容画到画布中
drawable.draw(canvas);
return bitmap;
} 二、Bitmap转换成Drawable
方法一：Drawable drawable = new BitmapDrawable(bitmap); 方法二：BitmapDrawable bd= new BitmapDrawable(getResource(), bm);BitmapDrawable是Drawable的子类，可以直接使用。
三、byte[ ]转换成Bitmappublic static Bitmap Bytes2Bimap(byte[] b) {

if (b.length != 0) {
return BitmapFactory.decodeByteArray(b, 0, b.length);
} else {
return null;
}

}四、Bitmap转换成byte[ ]public static byte[] getBytes(Bitmap bitmap){

ByteArrayOutputStream baos = new ByteArrayOutputStream();

bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);

return baos.toByteArray();

}