Android Question Infinite listview up and down

[demasi]

Hello,
I'm working on an APP for astronômical study, and would be very useful if I could have a list or other kind of view, that show a list where the user can select from a list, up and down, infinitely. The itens would be generated on the fly.
Do Someone know or have an idea on how I can implement this? I'm wondering to use something like pager view, but up and down, and I need to choose one item of this list, by clicking or touching.

 

[Erel]

See this thread: https://www.b4x.com/android/forum/posts/210230/

 

[demasi]

Thank you, Erel. I saw this, but i think this works for the end of the list. And how can I do the same for the top, when the list is moving down? I need to move two way.

 

[eurojam]

Hi,
that is an interesting question, infinite items would need also infinite RAM, may be that will be a problem....?

 

[demasi]

Its not really infinite. Maybe the best term should be "unknown" itens up or down. I will show years starting from current with some more data, and the user can go to the past or to the future in the list, a number of years, depending on his patience, and it could be 20, 100 or more than 1000 years. I managed to do this by using buttons for up and down, and regenerating the list for the range, 20 years, each press. But it would be much better and beaitiful to scroll the list with the finger as a normal listview.

 

[eurojam]

May be a wheel view is the right thing for that:
https://www.b4x.com/android/forum/threads/wheelview-library.17028/
or
https://www.b4x.com/android/forum/threads/spin-wheel.14620/

 

[demasi]

Wow! Fantastic! I will try this now. I think this view is exactly what I need. Thank you!

 

[demasi]

These wheels are very nice. I need something like this. But I need to have the ability to insert itens at the beginning or at the end when the user moves down or up. I was looking at Klaus code, but it is beyond my understanding, because I don't understand java, things like reflector, etc.

 

[klaus]

My wheels won't do it either.
They use limited lists.
For the 'continous scrolling' I add three times the list, instead of one time, to the wheel.
When the scrolling finishes in the first or third 'list' the wheel jumps to the middle list.

 

[johndb]

These wheels are very nice. I need something like this. But I need to have the ability to insert itens at the beginning or at the end when the user moves down or up. I was looking at Klaus code, but it is beyond my understanding, because I don't understand java, things like reflector, etc.

I would suggest that you have a look at the UltimateListView library https://www.b4x.com/android/forum/threads/lib-chargeable-ultimatelistview.22736/
I'm sure that It will do what you require.

 

[demasi]

I already have this fantastic lib. I use a lot in my apps with my kids, in the school. I make quizes, tests, internal communications and a lot of material to help the classes.
But for this purpose, I can´t see how can I use it, because I need to insert itens "on the fly", up and down, up to a limit defined only by the user's need.
thank you.