I have a simple problem:
i have a listview with 2 TextViews one shows a number and the other shows the diff from last time the number has chnaged.
What im trying to do is every time the getView is called on my adapter show an animation on the second TextView based on the change in the first Textview number. im trying to do this for all of the items inside the listview and it doesnt work.
What is the best way to achieve this?
Thanks,
Totem
The simplest way you can achieve this is by extending SimpleCursorAdaptor or ArrayAdaptor (How to...)
in the bindView method you based on the logical check you can then show the animated version of the TextView and hide the none animated.
This is the easiest way I have implemented.
http://thinkandroid.wordpress.com/2010/01/11/custom-cursoradapters/
Related
I am developing an activity with a ListView in which I need to change the current row by another layout by clicking on the row, and I'm not finding any way to do as much as I look (I take hours searching for possible solutions and I have not seen any reference to this problem). I do not know if this can be done in Android, but if anyone has an idea of how to do this would be appreciated.
Thanks in advance.
PS: The ListView control is normal and just want to replace a layout with a different layout. I'm using the API 15.
Use a ViewSwitcher
http://developer.android.com/reference/android/widget/ViewSwitcher.html
A ViewSwitcher is -
ViewAnimator that switches between two views, and has a factory from
which these views are created. You can either use the factory to
create the views, or add them yourself. A ViewSwitcher can only have
two child views, of which only one is shown at a time.
I suggest merging the two layouts in a single one and hide the second one. In your adapter data you should have a flag or something to indicate which layout to display. When you click a row, toggle that flag for the selected item and notifyDataSetChanged() on the adapter. This will make sure the changed layout remains even if you scroll up and down and the row goes off screen.
A more optimized solution is to have different item types in the adapter.
I'd like to change my listView items dynamically. The algorithm goes like this:
1.I create the default view for my listView using adapter and show it to user. The list item contains Imageview, textview and another imageview which is invisible.
2.The data is beeing dowloaded in the meantime.
3. after my data is downloaded, I'd like to check whether my listview contains any of downloaded items. If yes, I want to make visible the previously invisible ImageView for this item.
Should I add some kind of method to my adapter, call it and then call invalidateViews(), notifyDataSetChanged(), or notifyDataSetInvalidated()? Or maybe there is some kind of standard way to find my adapter's item by Id or sth and then make visible the imageview for this item?
This list update operation is the only one left to implement for me.
Should I add some kind of method to my adapter, call it and then call invalidateViews(), notifyDataSetChanged(), or notifyDataSetInvalidated()?
Yes, exactly.
maybe there is some kind of standard way to find my adapter's item by Id or sth and then make visible the imageview for this item?
Above mentioned way is enough. There is no such standard or special way to do it AFAIK.
Read the Displaying Bitmaps Efficiently introduction and in particular the part about Handle Concurrency. This will give you all the information you need.
What's the easiest way to create separate preferences for each item in an Android listview? I found this question, but it's kind of general. Could anyone be more specific, possibly show a quick example?
If you want to do this, you should write some code into your adapter getView method.
You can check the position (with an if-clause) in the method and add a custom desgin/layout depending on the position.
If you use a LinearLayout or RelativeLayout in your ListView item XML you can fill this programmatically in the getView method with all the widgets (edittext, checkbox, etc) you need.
I want to create a horizontal listview which contain many item, one item will contain a image. When user slide listview => the count of item will be fix when it display, example display only 3 or 4 image. How can I do that? Many thanks.
Edit:
I use this
to create a HorizontalList view, everything is ok but I don;t know how to make the Next and Previous button work! Any idea?
Instead of a horizontal ListView (which, as far as I know, isn't offered by the Android SDK) you can use a HorizontalScrollView. You can add the items like to any other kind of layout class.
It looks like what you are looking for is a Paginated Gallery. I have written one here.
Its still only a couple of days old but hopefully the included Activity code will get you off the ground.
l'm new here so hope to follow guidelines as I'm a newbie for both the side and android.
For my first app I'm trying to make a world clock.
In order to check it the time is shown and update in seconds. (00:00:00)
As the only thing I want to update every second is the time I don't want to use:
ListView's notfiyDataHasChanged()
I have a custom ListView & extended BaseAdapter and row.xml with each ListView item layout.
Trying:
lv.getChildCount() returns 0;
So I understand it has no child.
But I don't know how I can retrieve the View of the specific item in the listview.
Then call that view's TextView by findViewById(R.id.time) and set it each second.
I've googled and read alot of threads but still didn't get that :(
Thank You.
I would go a different way about that problem: Subclass the TextView widget into your own TimeView widget and include that one in your row layout.
The TimeView widget will own a handle that calls itself to refresh the view.
Hence, automatically, all views visible in the list will update themselves, the other adapter items will not be having views and won't as a consequence require any update.