从URL调整位图下载的大小以适合imageview空间：质量下降

Question

I know there are a lot of questions around this subject, but I cannot find something which perfectly fits my problem so I open this question in order to, at least, gather here EVERY aspect of the problem.

Let's start! I have my imageview and this imageview has to have fixed dimensions:

<ImageView
        android:id="@+id/my_image"
        android:layout_width="250dp"
        android:layout_height="170dp"
        android:layout_gravity="center_horizontal"
        android:layout_marginBottom="20dp"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="10dp"
        android:layout_marginTop="10dp"
        android:contentDescription="@string/cell_item_image"
        android:scaleType="fitXY" />

my bitmap comes from an url and is in the .jpg format, so my code is:

bitmap = BitmapFactory.decodeStream(conn.getInputStream());

its dimensions are 435x312 pixels, bigger than my screen density so scaling it should not lead to a loss of quality...how come I get an obfuscated image?

Is there a way to rescale bitmap and preseve quality?

Maybe it's that fitXY in the scale type? But what's the difference between scaling in code or in layout? I see many does that in code but, trying, I get exactly the same result

Answer 1

EDIT: read over the .jpg part

Try:

Options options = new BitmapFactory.Options();
options.inScaled = false;
Bitmap source = BitmapFactory.decodeResource(a.getResources(), path, options);

If this doesn't work, try displaying the image without scaling (this way you can see what causes the blur, the loading of the image or the displaying/scaling)