博客

一、Drawable 转换成 Bitmap

方法一

通过 BitmapFactory 中的 decodeResource 方法，将资源文件中的 R.drawable.ic_drawable 转化成Bitmap

Resources res = getResources();
Bitmap    bmp = BitmapFactory.decodeResource(res, R.drawable.ic_drawable);

方法二

将 Drable 对象先转化成 BitmapDrawable ，然后调用 getBitmap 方法 获取

Resource res      = gerResource();
Drawable drawable = res.getDrawable(R.drawable.ic_drawable);//获取drawable
BitmapDrawable bd = (BitmapDrawable) drawable;
Bitmap bm         = bd.getBitmap();

方法三

根据已有的Drawable创建一个新的Bitmap

    public static Bitmap drawableToBitmap(Drawable drawable) {

        int w = drawable.getIntrinsicWidth();
        int h = drawable.getIntrinsicHeight();
        System.out.println("Drawable转Bitmap");
        Bitmap.Config config =
                drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
                        : Bitmap.Config.RGB_565;
        Bitmap bitmap = Bitmap.createBitmap(w, h, config);
        //注意，下面三行代码要用到，否则在View或者SurfaceView里的canvas.drawBitmap会看不到图
        Canvas canvas = new Canvas(bitmap);
        drawable.setBounds(0, 0, w, h);
        drawable.draw(canvas);

        return bitmap;
    }

二、Bitmap 转换成 Drawable

使用 BitmapDrawable 对 Bitmap 进行强制转换

Drawable drawable = new BitmapDrawable(bmp);

三、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();   

    }

四、byte[] 转化成 Bitmap

    public static Bitmap Bytes2Bimap(byte[] b) {

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

    }