In an Android application I have a ListActivity. After creating it I have a broadcast receiver which has to disable some items in the list. So I have a pice of code ike this one:
View child = getListView().getChildAt(i);
child.setEnabled(false);
It works in the way it changes the color of the disabled views to gray. But I need to avoid this items can be clicked. So I've tried to call
child.setFocusable(false);
or
child.setClickable(false);
but in both cases onListItemClick is called after pressing on a disabled option.
How can I avoid that onListItemClick method is called when these textviews are clicked?
Thanks.
Disabling the views does nothing with regard to the onListItemClick event.
The child must be disabled by the Adapter you are using to populate the list.
See http://developer.android.com/reference/android/widget/ListAdapter.html#isEnabled(int)
This method needs to be overriden to return false for each item you do not want to be clickable. You should also add a method to your adapter like setEnabled(int position, boolean enabled)
Related
I'm making my first java android app and I'm having some issues with the RecyclerView.
I have a RecyclerView with a custom layout for each element.
I want to make that when I press the toolbar button, the Image Buttons inside EACH layout element inside the RecyclerView turn visible or invisible
This is the toolbar edit button code:
ArrayList<View> dest=new ArrayList<View>();
recView= findViewById(R.id.newListView);
recView.setItemViewCacheSize(0);
recView.findViewsWithText(dest,getString(R.string.onesingleuserlayout),View.FIND_VIEWS_WITH_CONTENT_DESCRIPTION);
for (View oneUserLayout:dest)
{
oneUserLayout.findViewById(R.id.btnDelete).setVisibility(newVisibility);
oneUserLayout.findViewById(R.id.btnEdit).setVisibility(newVisibility);
}
It hides almost all the elements, but not every one of them. The ones shown behave correctly, and SOMETIMES the ones not showing don't.
I think that it is related to the cached items.
Remove this line, in order to permit caching:
recView.setItemViewCacheSize(0);
Here it's explained how it works (which may also explain, why caching is required).
Try to change your approach and instead of calling all those findView methods from outside the RecyclerView, implement a method on the adapter to change a boolean variable representing the visibility of the buttons and then call notifyDataSetChanged to force the layout manager to redraw all the visible itens and since all items reference the boolean variable, when new items are redrawn they will have the new visibility.
I have list/rows of checkboxes inside recycle view. In my case, the user can only select 3 checkboxes out of many. As soon as the user selects the third checkbox, I want to disable rest of the checkboxes in different rows.
I am capturing selecting/deselecting checkboxes inside adapter class.
As far as I know, I can enable/disable checkboxes inside onBindViewHolder class.
But in my case, I want to enable/disable checkboxes, after they have been rendered.
One of the approaches I can think is, to call notifyDataSetChanged(); from Activity class and then rerender all the recycled view.
But I hope there is the better way than doing this, inside the adapter class itself.
ps: I am new to android/java.
notifyDataSetChanged() will defently work in your case.
Please note that you don't have to call this method from the Activity.
You can call it internally within your adapter after the third checkbox was selected.
From the top of my head, One way to do this would be to store the "checked" positions indide an array within the adapter, then inside onBindViewHolder() check to see if the current position should be enabled or disabled.
In your model class you can have a boolean variable that decide whether the item should be enabled or not and another boolean variable to keep track of the checked state, or if the item is checked or not. In onBindViewHolder check the variable to enable or disable the item.Keep track of the selected items and then after every check and uncheck, check if the selected items exceeds the limit. Then loop through your items and then check if the item is checked or not. if the item is not checked set the value to false and after the loop send a notifyDataSetChanged() and in onBindViewHolder() check for the value and enable or disable the item/checkbox
You can use SparseBooleanArray to record all the changes for each item based on their positions.
You can use the following method in RecyclerView adapter:
notifyItemInserted(int)
notifyItemRemoved(int)
notifyItemRangeChanged(int, int)
notifyItemRangeInserted(int, int)
notifyItemRangeRemoved(int, int)
Read more at RecyclerView.Adapter.
Only use notifyDataSetChanged() as the last resort. Because calling notifyDataSetChanged() will force the views to rebind and relayout. As in the documentation says:
void notifyDataSetChanged ()
Notify any registered observers that the data set has changed.
There are two different classes of data change events, item changes
and structural changes. Item changes are when a single item has its
data updated but no positional changes have occurred. Structural
changes are when items are inserted, removed or moved within the data
set.
This event does not specify what about the data set has changed,
forcing any observers to assume that all existing items and structure
may no longer be valid. LayoutManagers will be forced to fully rebind
and relayout all visible views.
RecyclerView will attempt to synthesize visible structural change
events for adapters that report that they have stable IDs when this
method is used. This can help for the purposes of animation and visual
object persistence but individual item views will still need to be
rebound and relaid out.
If you are writing an adapter it will always be more efficient to use
the more specific change events if you can. Rely on
notifyDataSetChanged() as a last resort.
I'm new to Android development.
I need to make a listview with text and icon audio player. The icon has three States, "download", "downloading", "play" and "pause". The idea is that when populating the listview, set the "download" icon if the track is not downloaded and "play" if the track is downloaded". If a person clicks the "download" button the icon should be updated to "downloading" to start the download, then when complete, you should see the icon "play". If the user presses the "play" icon for this element should be updated to "pause".
I can't change the icon . I tried to change them in onItemClickListener and make the onClick in the getView method in adapter, but when scrolling the icons changed to the old. And if you select multiple items in the list, then change all the icons, and I need to change only one, for playing of the track.
I didn't show the code because there is nothing that can be corrected. - all wrong
if you have your own adapter try using a method notifyDataSetChanged();
That is happening due to recycling of views. If you click on an item and you will see multiple items clicked.
Use RecyclerView instead of listView, which will handle recycling by its own and its ViewHolder class takes care of the issue you are having.
And don't forget to notify the recyclerView adapter whenever you make some change in data source (i.e. arraylist)
Check out this example...
Hope it helps
http://hmkcode.com/android-simple-recyclerview-widget-example/
When I place a CheckBox in the row layout for a ListView, I am no longer able to recieve OnItemClick and OnItemLongClick events. On the other hand, using CheckedTextView allows these events to go through, but I don't know how to automate clicking on them in my JUnit/Robotium tests. Does anyone have any suggestions about what I can do to get the best of both worlds here?
You can make OnItem(Long)Click work if you set up the CheckBox views to non-focusable (i.e. setFocusable(false) and setFocusableInTouchMode(false), or their xml equivalents).
Note: The listeners will fire as long as you tap outside the checkbox itself. Tapping on the checkbox will toggle it only (but I guess this is what you would want).
I tried to found a method, but no results. I want a ListView like below, and when I click on an element, like "Word", it'll be like this picture :
Is it possible ?
What you described is what an ExpandableListView does.
Basically it's like a listview so you'll still have to create your own adapter, but it lets you click a row to inflate a bigger item that you can then stuff your text into.
I would recommend creating your own class that extends ArrayAdapter or BaseAdapter. Then you can make use of the getView() method that gets called every time the screen gets redrawn for the user. You can then design multiple views for each selection and choose which one to display in the getView() function. So when the user selects an item, you set a flag in your custom class, and then notifyDataSetChanged() and you're good to go!