How to set DialogFragment's width and height?

If you convert directly from resources values:

int width = getResources().getDimensionPixelSize(R.dimen.popup_width);
int height = getResources().getDimensionPixelSize(R.dimen.popup_height);        
getDialog().getWindow().setLayout(width, height);

Then specify match_parent in your layout for the dialog:

android:layout_width="match_parent"
android:layout_height="match_parent"

You only have to worry about one place (place it in your DialogFragment#onResume). Its not perfect, but at least it works for having a RelativeLayout as the root of your dialog's layout file.

I ended up overriding Fragment.onResume() and grabbing the attributes from the underlying dialog, then setting width/height params there. I set the outermost layout height/width to match_parent. Note that this code seems to respect the margins I defined in the xml layout as well.

@Override
public void onResume() {
    super.onResume();
    ViewGroup.LayoutParams params = getDialog().getWindow().getAttributes();
    params.width = LayoutParams.MATCH_PARENT;
    params.height = LayoutParams.MATCH_PARENT;
    getDialog().getWindow().setAttributes((android.view.WindowManager.LayoutParams) params);
}

I got a fixed size DialogFragment defining the following in the XML main layout (LinearLayout in my case):

android:layout_width="match_parent"
android:layout_height="match_parent"
android:minWidth="1000dp"
android:minHeight="450dp"