I have a listview that displays a list of profiles added by a user. If no profiles exist, I set the listview visibility to "gone".
I have a context menu on the listview that allows a user to delete a profile. When doing this, I display a dialog window to confirm they want to delete the profile.
If the user selects "Yes" on the dialog by touching the button, everything works fine.
If the user selects "Yes" using the trackball, then touches the screen, the app crashes.
I can prevent the crash by commenting out the line of code that sets the listview visibility to "gone". I'm curious what's causing the crash (want to understand).
The error seems misleading to me, which is:
java.lang.IllegalStateException: The content of the adapter has changed but ListView did not receive a notification. Make sure the content of your adapter is not modified from a background thread, but only from the UI thread
The adapter that the ListView was using just needed to be notified that the data changed (notifyDataSetChanged()). Still not sure why the behavior is different between using the trackball vs touch, but I have a better understanding of how the adapter works now.
Related
I have couple of issues in the process of making my app accessibility compliant.
I have a spinner with some items in it, after I select one of the item, spinner closes and focus is moving to the top of the page action bar but I want the focus to remain on the last used element i.e, the spinner. Tried:
spinnerId.requestfocus(); or spinnerId.performAccessibilityAction(AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS,null); in the code but nothing worked.
2.How can I set the focus to last accessed element even if onResume(); is called to refresh the data ?
3.Page reverse order doesn't work all the time when I scroll back through the elements.
4.I have a listview with elements populated dynamically, accessibility doesn't scroll the page all the times instead it goes to right fragment( i have left and right fragments in my tablet) skipping the elements below the screen.
As your spinner is already focus, you have to clear this focus, send this event to Accessibility and request it again:
yourView.clearFocus();
yourView.sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_FOCUSED);
yourView.requestFocus();
yourView.setFocusableInTouchMode(true);
He took me awhile to find this tricks, but we used it in few different place in our app, and it work well.
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 have a scenario where I want to programmatically change the value of my spinner using setSelection(). This works great, except that if the spinner is open (expanded?) an the time, the spinner does not close. Eg, the menu stays up, despite calling setSelection().
How can I programmatically close the spinner? I have tried performClick() to no avail.
edit: more details:
The reason I'm trying to do this is that my spinner actually uses a compound layout for each selection row. Namely, I have a linearlayout which contains an image, text, and button. The idea was that the button serves as an "edit" button (which opens an activity), while pressing on the image/text select the row (per usual).
The problem came when I added the button. Suddenly, the image & text no longer captured the press event to change the combo. In other words, adding a button to the row destroyed the touch-handling capacity of the entire row. So I tried to manually implement a click handler for the image/text, which subsequently executed a setSelection... which is where I ran into this problem.
You say that after adding the button you lost the click handle on the entire row. Try adding this android:descendantFocusability="blocksDescendants" to your row layout, and see if you can get the clicks to work properly.
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.
I have just started my career as an android programmer, and am currently relying heavily on the sample code and api examples. I have been working with this api example, to produce an expandable list of items (note this example does not use the ExpadableListView).
In playing with the example, I tried to add another widget that would become visible and be gone at the same time as the text (mDialogue in the sample code). This works well with another TextView, but as soon as I tried to add a button widget, it stopped working. The list would expand on first click, showing my hidden TextView and Button, but it will not disappear on further clicks. The button is however, clickable, and I was able to set up an onClick listener to change the button text back and forth.
I'm starting to wonder, is it just not possible to have a clickable item inside a clickable list item? Or is there some kind of work around? Would it solve my problem if I used ExpandableListView?
You have two options of how to handle focus within a ListView controlled by ListView#setItemsCanFocus(boolean). If you want individual Views within a list item to focus so that the user can interact with them individually instead of with the list item as a whole, call it passing true. false is the default behavior.
The default behavior where ListView manages item focus and clicks is basically a shortcut/optimization for the common case where the whole item acts as a single unit from an interaction standpoint, but its layout may be complex. When you tell ListView that its items can focus it disables this special behavior and you should use the more traditional mechanisms of handling events on the Views within the list items. (Listeners, overridden on* methods, etc.)
But why do your list items stop taking clicks when your ListView isn't set up for focusable items? ListView will only generate item click events if the list item view returns false from View#hasFocusable(). This means no children of the list item can be focusable if you want to receive item click events for it. As soon as your button becomes visible, the list item has a focusable child and will no longer receive list item click events.