How to highlight row in ListView in Android?

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天涯浪人
天涯浪人 2020-11-27 06:05

I need to highlight a row in a ListView that was selected (to show the user what he chose), so, it\'s not the one that is going to be chosen, it\'s the one he c

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  • 2020-11-27 06:34

    I solve this problem in the following way: 1. set a lastClickId, when click the item in listView, update the lastClickId to position value, then update the view's background. After this, when we click one item, this item will be highlighted, but when we scroll the listView(make the item which we selected out of the screen) and scroll back, the highlight is gone, because the method getView() rerun in your adapter, so, we have to do the next thing. 2. in your adapter, change the background in the method getView(), here is the code:

    private static int lastClickId = -1;
    private OnItemClickListener listener = new OnItemClickListener() {
    
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position,
                long id) {
            if ((lastClickId != -1) && (lastClickId != position)) {
                parent.getChildAt(lastClickId).setBackgroundResource(
                        R.color.grey);
                view.setBackgroundResource(R.color.blue);
            }
            if (lastClickId == -1) {
                view.setBackgroundResource(R.color.blue);
            }
            lastClickId = position;
    
        }
    
    };
    
    public static int getCurrentSelectedItemId() {
        return lastClickId;
    }
    

    Adapter:

    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
    
        View view = mInflater.inflate(R.layout.tweet_list_layout, null);
        // set selected item's background to blue
        if (position == MainUserFeedFragment.getCurrentSelectedItemId()) {
            view.setBackgroundResource(R.color.blue);
            }
        }
    
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  • 2020-11-27 06:37

    Since by default ListViews are set to a selection mode of NONE, in touch mode the setSelection method won't have visual effect.

    For keeping the previous selection / visually display an explicit selection, first you must set your listview's choice mode appropriately:

    listview.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
    

    It's useful to read the API Docs of these methods:

    • setSelection
    void android.widget.AdapterView.setSelection(int position)
    

    Sets the currently selected item. To support accessibility subclasses that override this method must invoke the overriden super method first.

    Parameters:
    position Index (starting at 0) of the data item to be selected.

    • setChoiceMode
    void android.widget.ListView.setChoiceMode(int choiceMode)
    

    Defines the choice behavior for the List. By default, Lists do not have any choice behavior (CHOICE_MODE_NONE). By setting the choiceMode to CHOICE_MODE_SINGLE, the List allows up to one item to be in a chosen state. By setting the choiceMode to CHOICE_MODE_MULTIPLE, the list allows any number of items to be chosen.

    Parameters:
    choiceMode One of CHOICE_MODE_NONE, CHOICE_MODE_SINGLE, or CHOICE_MODE_MULTIPLE

    In case this is not enough (say you'd like to always show the last selection differently beside the current selection), you should store your last selected item (a data which populates the ListAdapter) as lastSelectedItem, and in your adapter's getView method assign a different background resource to the renderer if it equals this lastSelectedItem.

    If your last selection wouldn't refresh on selection change, you should explicitly call the notifyDataSetChanged method on your adapter instance.

    Update
    Since your activity containing the ListView is a child of an activity which waits for this one's result (based on the setResult(Activity.RESULT_OK,pongIntent); part), the initial idea is correct, the last position should be passed through the intent when starting the activity:

    selectedListItem = getIntent().getIntExtra("PositionInList", -1);
    lvUsers.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
    lvUsers.setSelection(selectedListItem);
    

    The ListView.CHOICE_MODE_SINGLE solution would work if you remain in the same activity, but you are finishing it on every itemClick (selection change), that's why the extra data should be passed to the starting Intent.

    You can also set the previously selected item's background from your adapter -as mentioned above-, overriding its getView method:

    lvUsers.setAdapter(new ArrayAdapter(this, R.id.counlistView, groups)
    {
        @Override
        public View getView(int position, View convertView, ViewGroup parent)
        {
            final View renderer = super.getView(position, convertView, parent);
            if (position == selectedListItem)
            {
                //TODO: set the proper selection color here:
                renderer.setBackgroundResource(android.R.color.darker_gray);
            }
            return renderer;
        }
    });
    
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