You call measureChildren() which in turns call measureChild() which looks
at the LayoutParams of each child.
On Mar 1, 2013 10:12 PM, "momo" <[email protected]> wrote:
> I have a custom ViewGroup that's only ever managing the size and position
> of one child. I've override onMeasure and onLayout so that LayoutParams
> are never examined, yet it fails unless I do provide LayoutParams. Here
> are abbreviated summaries of the relevant portions of the class:
>
>
> public class SomeSpecialLayoutManager extends ViewGroup {
>
> @Override
> protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
> measureChildren(widthMeasureSpec, heightMeasureSpec);
> int w = mChild.getMeasuredWidth();
> int h = mChild.getMeasuredHeight();
> w = Math.max(w, getSuggestedMinimumWidth());
> h = Math.max(h, getSuggestedMinimumHeight());
> w = resolveSize(w, widthMeasureSpec);
> h = resolveSize(h, heightMeasureSpec);
> setMeasuredDimension(w, h);
> }
>
> @Override
> protected void onLayout(boolean changed, int l, int t, int r, int b) {
> mChild.layout( 0, 0, mWidth, mHeight );
> }
> }
>
>
> Using the above, the following *does* work:
>
> LayoutParams lp = mChild.getLayoutParams();
> lp.width = mWidth;
> lp.height = mHeight;
> mChild.setLayoutParams( lp );
>
> But since neither `onMeasure` nor `onLayout` even makes reference to
> `LayoutParams`, I wonder why it's required, or even how it's referenced at
> all. I would assume that since the layout pass grabs `mWidth` and
> `mHeight` directly, there'd be no need for the `LayoutParams` at all - and
> that a call to requestLayout would update it appropriately.
>
> However, when I isolate the above in a small program outside of a
> complicated View tree with scrolling layers that exceed "normal" container
> sizes, it *does* work as expected, so I have to assume the issue is in the
> measure pass.
>
> I've read as much documentation as I can find about what's going on during
> the measure and layout passes, and examined the source, but I believe I
> must be missing something.
>
> TYIA.
>
> --
> --
> You received this message because you are subscribed to the Google
> Groups "Android Developers" group.
> To post to this group, send email to [email protected]
> To unsubscribe from this group, send email to
> [email protected]
> For more options, visit this group at
> http://groups.google.com/group/android-developers?hl=en
> ---
> You received this message because you are subscribed to the Google Groups
> "Android Developers" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to [email protected].
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>
--
--
You received this message because you are subscribed to the Google
Groups "Android Developers" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/android-developers?hl=en
---
You received this message because you are subscribed to the Google Groups
"Android Developers" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/groups/opt_out.
