Bitmap + Drawable 使用與轉換

建立Drawable

Drawable d = getResources().getDrawable(R.drawable.ic_launcher);

建立Bitmap

➀ 型態為int的Drawable → Bitmap

    Bitmap bm = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);

➁ Drawable → Bitmap

    Bitmap drawableToBitmap(Drawable drawable)
    {         
        Bitmap.Config c =drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565;
        Bitmap bitmap = Bitmap.createBitmap( drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(),  c);
        Canvas canvas = new Canvas(bitmap);
        drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
        drawable.draw(canvas);
        return bitmap;
    }

➂ File → Bitmap

    String filePic = "/mnt/sdcard/dcim/sample.png";
    File f = new File(filePic);
    if(f.exists())
    {
        Bitmap bm = BitmapFactory.decodeFile(f);
    }

➃ FileDescriptor → Bitmap

    Bitmap bm = BitmapFactory.decodeFileDescriptor(FileDescriptor fd);

➄ Stream → Bitmap

    try
    {
        URL url = new URL(imageUrl);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.connect();
        InputStream is = conn.getInputStream();
        Bitmap bm = BitmapFactory.decodeStream(is);
        is.close();
    }
    catch (IOException e)
    {
        e.printStackTrace();
    }

⑥ byte[] → Bitmap

    byte[] b;
    if(b.length!=0)
    {
        Bitmap bm = BitmapFactory.decodeByteArray(b, 0, b.length);
    }

建立BitmapDrawable

BitmapDrawable bmd = new BitmapDrawable (bm);

=====================其它轉換=====================

Drawable → BitmapDrawabl → Bitmap
    BitmapDrawable  bd = (BitmapDrawable)d;
    Bitmap bitmap = bd.getBitmap();

Bitmap → Drawable
    Drawable drawable = new BitmapDrawable(bm);

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

=====================顯示=====================

ImageView iv = (ImageView) findViewById (R.id.iv_pic); iv.setImageBitmap(Bitmap bm);
iv.setImageResource(int resId);
iv.setImageDrawable(Drawable drawable);
iv.setImageDrawable(BitmapDrawable bmd);
iv.setImageBitmap(Bitmap bm);

=====================附錄=====================

➀	BitmapFactory.decodeByteArray(byte[] data, int offset, int length)
➁	BitmapFactory.decodeByteArray(byte[] data, int offset, int length, BitmapFactory.Option opts)
➂	BitmapFactory.decodeFile(String pathName)
➃	BitmapFactory.decodeFile(String pathName, BitmapFactory.Option opts)
➄	BitmapFactory.decodeFileDescriptor(FileDescriptor fd)
➅	BitmapFactory.decodeFileDescriptor(FileDescriptor fd, Rect outPadding, BitmapFactory.Option opts)
➆	BitmapFactory.decodeResource(Resources res, int id)
➇	BitmapFactory.decodeResource(Resources res, int id, BitmapFactory.Option opts)
➈	BitmapFactory.decodeStream(InputStream Is)
➉	BitmapFactory.decodeStream(InputStream Is, Rect outPadding, BitmapFactory.Option opts)