I need all of the other views in my arrayadapter to check their attributes and return to a default attribute at certain times
use case: listview items (a)(b)(c)(d) , when you touch (a) it's background turns black. This is done in the ontouchListener. But when you touch view (b) it's background turns black BUT (a)'s needs to turn back to the default which is not black
I dabbled around with recalling the arrayadapter at the end of the view.OnClickListener but the problem with this is that it also resets the scroll position of the view, so if this list was much longer - which it is - and user touched item (r) , then it would reset the list and put the user back at item (a) at the top
I was looking at notifydatasetchangedbut I am not sure how to use that and where it should work
insight appreciated
notifyDataSetChanged will do the job. You can call that at any time in your code and this will trigger the adapter to call getView for the visible list items again and so update their content. So basically the only thing you have to do is to update the list item states or information before calling that method.
Related
I have a situation involving animation of listview's item appearances.
I have a few views in a ScollView , the last of which is the listview. I have attached an appearence animation of the row (a fade in animation).
The problem I have is that when the screen is loaded , the getView() of listview already executes for the initial items , even though the listview is not currently in view.
Hence when a user scroll downs , he sees the list plainly.
I am unsure how to go about this situation . Is there any callback that can be invoked when a row from a listview becomes visible on screen ? .
Yes there is a callback (OnScrollChangeListener), first visible index and last visible index etc. You can achieve what you are trying to using combination of these.
But you need to try that yourself first. No one can simply write a code for you.
You can learn about listview here
I want my ListView to work something like the following:
When I press a button (probably from context-menu), I want the user to be able to select more then one item from ListView (probably using check-boxes), but those check-boxes should not be visible before that.
So, the point is, after the user presses a button (let's say "Delete more items"), the listview, should update itself, and appear on every row of the list, a checkbox should appear (allowing me to select the items ID to pass those to server).
How can I achieve that, without having to recreate the list from zero? (how to setVisibility ON, keeping the other content of the ListView as it is, and not doing another request to server).
PS. If you guys, have another better idea, on achieving the Delete More Items, would be much appreciated!
This is just an idea, haven't tried it myself: you build in a checkbox in your listitem layout. Normally, in the getView of your adapter, you set it invisible with
checkBox.setVisibility(8);
When you want to show them, you set some boolean
showBoxes
of your adapter to true, then in the getView oyu don't hide the checkboxes.
Then
notifyDataSetChanged
on the adapter.
Hope it's clear what I mean.
I know Android execute 2 times (or sometimes even more) the getView() method of the adapter in order to draw the ListView correctly. I would like to know (or get notified) when it stops execute that method.
Why? The rows of my list are animated when user swipes on one of them. If the user swipes before Android has finished execute getView(), the animation is executed on the first row instead of the row touched by the user.
You can load ListView in background AsyncTask. And during that time you can show progress dialog on the screen so user is not able to do any action on your screen.
Check this Reference :
Load ListView in background AsyncTask
Hope this helps you.
Thanks.
There is no last getView()
When you are scrolling in a list, for each item that will become visible a getView() will be called. EVEN when it has already been on screen. I believe you are not detecting the list view item click properly.
I have following code that works fine when my ListView is already rendered (eg. when fired by onClick events, etc.)
TextView tv = (TextView)list.getChildAt(position); //list is my ListView
if (tv!=null) {
tv.setPaintFlags(tv.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
}
However, sometimes I need to apply this STRIKE_THRU_TEXT_FLAG flag to some items of ListView when activity is being restored (after rotation, restart...). If I try to run this code in onCreate or onStart methods then list.getChild(position) returns null because no ListView item is visible yet (in fact screen is black at this time and actual drawing seems to be done in some later function).
Is there any easy way how to get around this? Maybe getChild function is not the best for this case...Or would you override rendering function of the ListView to make it work (seems like overkill to me)? Thanks
Don't modify the view itself like that; modify the actual data object that represents that list item (for example, if your ListView is backed by an ArrayAdapter, this would be the array item for that list position). You could set a flag or property to denote that the item should be displayed differently, and then add some conditional code to your adapter's getView() method to display the text in the proper style based on the properties of that list item's object.
You can then let the view render itself accordingly the next time it's shown, or trigger the redraw yourself by calling notifyDataSetChanged() on the list adapter.
In Android, I want to present the user with a list. When an item on the list is selected some action is performed, and this list item is no longer selectable. It is also 'grayed out' or the like to indicate that it cannot be selected the next time the list is displayed. I have seen the isSelectable() override in Adapter, but I believe this causes the item to be treated as a separator, which causes visual problems. And I have not found a way to 'gray out' an item. Any ideas? Thanks...
As far as graying out an item. I'm not sure if this is the best way, but it's what I do:
view.setAlpha(75);
view.setBackgroundColor(Color.GRAY);
I'm basically making the item transparent and then setting the background color to gray. If you're reusing your list items you should also change them back to their original state if the condition is not met, i.e.:
view.setAlpha(255);
view.setBackgroundColor(Color.WHITE);
that is, if your original state was no transparency and the background color was white.
You need the view to be disabled. If you are creating the views just call .setDisabled(boolean) on the top view. Setting the list item to be disabled doesn't work very well in my experience.
Here is the solution I am using. I set up an OnItemClickListener for my ListView. When an item in the list is clicked, I take the passed in View and call setEnabled(false) on it. This will gray out the item. However, subsequent clicks on this item will still call the onItemClick method. So, you will need to check on each click if the item is enabled/disabled and act accordingly.