Question

Hi I am trying to draw a complex view, defined by an xml layout to a Bitmap (which is afterwards drawn to a canvas). That view is then updated regularly, when something changed in the data model.
Changing statically defined TextView works perfect, but adding new Views to a linearLayout is somehow not working. Where is my mistake?

This is how I am adding new Views:

           linearLayoutContainer.removeAllViewsInLayout();

            for (int i = 0 ; i < 5; i ++) {

                TextView child = new TextView(getContext());
                child.setText("example" + i);
                child.setVisibility(View.VISIBLE);
                linearLayoutContainer.addView(child, i , new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.FILL_PARENT));
                i++;
            }

this is how I am crating the bitmap:

    sideBarView.refresh();
    sideBarView.invalidate();
    sideBarBitmap = sideBarView.getDrawingCache();

which works perfectly for updating the already in xml defined TextViews, but the new added views are not visible.

My xml layout looks like that:

<?xml version="1.0" encoding="utf-8"?>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="some"
    android:textSize="20dp" />

<LinearLayout
    android:id="@+id/linearLayoutContainer"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_weight="0.33"
    android:gravity="center_horizontal" >

<!-- THE CONTAINER -->

</LinearLayout>

<LinearLayout
    android:id="@+id/linearLayout1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_gravity="center"
    android:layout_weight="0.66"
    android:gravity="center"
    android:orientation="horizontal" >

<TextView
    android:id="@+id/TextView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_margin="2dp"
    android:text="20%"
    android:textSize="30dp" />

<TextView
    android:id="@+id/TextView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_margin="3dp"
    android:text="35%"
    android:textSize="30dp" />

</LinearLayout>

Answer 1

I solved my problem. After refreshing my view by adding new views I should have called measure on the root view again. This is what I did wrong (in pseudo code):

init code:
created rootView
measure 
getDrawingCache
draw

update code:
update rootView
invalidate rootView
getDrawingCache
draw

So the problem was in the update code, which did not called measure again, so that the child views have not been remeasured , which of course does not happen when adding a view inside an activity, so thats what is needed:

update code:
update rootView
measure
invalidate rootView
getDrawingCache
draw

and in real code:

private void refreshViews() {

    sideBarView.refresh();

    sideBarView.measure(
            MeasureSpec.getSize(sideBarView.getMeasuredWidth()),
            MeasureSpec.getSize(sideBarView.getMeasuredHeight()));
    sideBarView.layout(0, 0,
            MeasureSpec.getSize(sideBarView.getMeasuredWidth()),
            MeasureSpec.getSize(sideBarView.getMeasuredHeight()));

    sideBarView.invalidate();
    sideBarView.buildDrawingCache();
    sideBarBitmap = sideBarView.getDrawingCache();
}