Measuring a ViewPager

Question

I have a custom ViewGroup that has a child ViewPager. The ViewPager is fed by a PagerAdapter that provides a LinearLayout to the

Answer 1

Looking at the internals of the ViewPager class in the compatibility jar:

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
    // For simple implementation, or internal size is always 0.
    // We depend on the container to specify the layout size of
    // our view. We can't really know what it is since we will be
    // adding and removing different arbitrary views and do not
    // want the layout to change as this happens.
    setMeasuredDimension(getDefaultSize(0, widthMeasureSpec), getDefaultSize(0, heightMeasureSpec));

   ...
}

It would appear that the ViewPager implementation does not measure the children views but just sets the ViewPager to be one standard view based on what the parent is passing in. When you pass wrap_content, since the view pager doesn't actually measure its content it takes up the full available area.

My recommendation would be to set a static size on your ViewPager based on the size of your child views. If this is impossible (for instance, the child views can vary) you'll either need to pick a maximum size and deal with the extra space in some views OR extend ViewPager and provide a onMeasure that measure the children. One issue you will run into is that the view pager was designed not to vary in width as different views are shown, so you'll probably be forced to pick a size and stay with it