Drawable、Bitmap、byte[]之间的转换问题

分类： Android Development technology 2011-07-14 11:17 97人阅读 评论(0) 收藏 举报

Android在处理一些图片资源的时候，会进行一些类型的转换，整理如下：

1、Drawable → Bitmap 的简单方法
((BitmapDrawable)res.getDrawable(R.drawable.youricon)).getBitmap();

2、Drawable → Bitmap

Java代码
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;
}

Bitmap→Drawable 
BitmapDrawable bitmapDrawable = (BitmapDrawable)bitmap;
Drawable drawable = (Drawable)bitmapDrawable;
Bitmap bitmap = new Bitmap (...);
Drawable drawable = new BitmapDrawable(bitmap);

3、从资源中获取Bitmap
Java代码
Resources res=getResources();

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

4、Bitmap → byte[]
Java代码
private byte[] Bitmap2Bytes(Bitmap bm){
    ByteArrayOutputStream baos = newByteArrayOutputStream(); 
    bm.compress(Bitmap.CompressFormat.PNG, 100,baos); 
    return baos.toByteArray();
   }

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