Values disappearing from a Listview on Scroll - Android

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难免孤独
难免孤独 2020-12-20 04:18

I have a custom adapter extended from the SimpleCursorAdapter. Using this I\'m binding a ListView which contains a checkbox and Two textboxes. On opening the activity, the l

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  • 2020-12-20 04:46

    Android does not render all ListView entries at once, but only those visible on the screen. When "new" List-Rows come into view the

    public View getView(int position, View convertView, ViewGroup parent)
    

    method of your Adapter gets called and the view is recreated. To fill in previousely saved values you probalby have to overwrite the getView method.

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  • 2020-12-20 04:48

    Listview tends to recreate its views every time your list is scrolled up or down. You need to have some kind of model class that can save the state of your checkbox and textbox in memory in case some change is done(for that particular row) and later display it on the view.

    As mentioned on other answers in this post u can use getview to programatically induce values that you have stored in your model classes to your views based on the list view position.

    Something like this

     @Override
            public View getView(int position, View convertView, ViewGroup parent) {
                System.out.println("getView " + position + " " + convertView);
                ViewHolder holder = null;
                if (convertView == null) 
                {
                    convertView = mInflater.inflate(R.layout.item1, null);
                    holder = new ViewHolder();
                    holder.textView = (TextView)convertView.findViewById(R.id.text);
                    convertView.setTag(holder);
                } 
               else {
                    holder = (ViewHolder)convertView.getTag();
                }
               // Pass on the value to your text view like this. You can do it similarly for a check box as well
                holder.textView.setText(mData.get(position));
                return convertView;
            }
    
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  • 2020-12-20 04:55

    You need to have an arraylist of the states of each item in the list,, then load these states each time the list item view is loaded.Do this by overriding GetView() method in the adapter and add your saved state to the list based on the item position

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