Picker List is Too Short

One of the Newton 2.x OS Q&As
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This document was exported on 7/23/97.

Picker List is Too Short (4/29/96)

Q: I have items in my picker list with different heights that I set using the fixedHeight slot. When I bring up the picker, it is not tall enough to display all the items. Worse, I cannot scroll to the extra items. What is going on?

A: The fixedHeight slot is used for two separate things. Any given pick item can use the fixedHeight slot to specify a different height. This works fine.

However, the code in Newton 2.0 OS that determines how big the list should be also uses the fixedHeight slot of the first pick item (in other words, pickItems[0]) if it exists. It is as if the following code executes:

local itemHeight := kDefaultItemHeight;
if pickItems[0].fixedHeight then
   itemHeight := pickItems[0].fixedHeight;
local totalHeight := itemHeight * Length(pickItems);

This total height is used to figure out if scrolling is required. As you can see, this can cause problems if your first item is not the tallest one. The solution is to make sure the first item in your pickItems array has a fixedHeight slot that is sufficiently large to make scrolling work correctly. This may be fixed in future revisions of the NewtonOS.

Note that there will be similar problems if your pick items contain icons. The system will use the default height unless you specify a fixedHeight slot in your first item. The default height is not tall enough for most icons. In other words, if you have icons in your pick items, you must have a fixedHeight slot in the first item that is set to the height of your icon.