android 图片转换

1. Bitmap 转化为 byte

ByteArrayOutputStream out = new ByteArrayOutputStream();

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

byte[] array= out.toByteArray();

2. byte转化为bitmap

Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);

3. bitmap转化为Drawable

Drawable drawable = new FastBitmapDrawable(bitmap);

4. Drawable转化为bitmap

a. BitmapDrawable, FastBitmapDrawable直接用getBitmap

b. 其他类型的Drawable用Canvas画到一个bitmap上

Canvas canvas = new Canvas(bitmap)

drawable.draw(canvas)

5.id转化graphic.drawable

Drawable drawable = getResources().getDrawable(R.drawable.icon);

6.id转化成Bitmap

Bitmap bitmap = BitmapFactory. decodeResource (Resources res, int id)