How to Load The Listview "Smoothly" in Android

How to load the Listview smoothly in android

I will describe you how to get such issue that you have. Possibly this will help you.

So, in list adapter you have such code:

public View getView(int position, View contentView, ViewGroup arg2)
    {
        ViewHolder holder;

        if (contentView == null) {
            holder = new ViewHolder();
            contentView = inflater.inflate(R.layout.my_magic_list,null);
            holder.label = (TextView) contentView.findViewById(R.id.label);
            contentView.setTag(holder);
        } else {
            holder = (ViewHolder) contentView.getTag();
        }

        holder.label.setText(getLabel());

        return contentView;
    }

As you can see, we set list item value only after we have retrieved holder.

But if you move code into above if statement:

holder.label.setText(getLabel());

so it will look after like below:

if (contentView == null) {
   holder = new ViewHolder();
   contentView = inflater.inflate(R.layout.my_magic_list,null);
   holder.label = (TextView) contentView.findViewById(R.id.label);
   holder.label.setText(getLabel());
   contentView.setTag(holder);
}

you will have your current application behavior with list item duplication.

Possibly it will help.

Make ListView Scroll Smoothly

You should use recyclerView instead. It is a more advanced and flexible version of ListView. Go through https://developer.android.com/guide/topics/ui/layout/recyclerview for guide.

If you want to stick with ListView then in order to improve the performance you should recycle/reuse the views that are no longer visible to the user.

public View getView(final int i, View convertView, ViewGroup viewGroup) {
       
    Holder holder = null;
    if(convertView == null){
        convertView = inflater.inflate(R.layout.contact_inflater, null);
        final Holder holder = new ContactAdapter.Holder();
        holder.ivPhoto = (ImageView) convertView.findViewById(R.id.ivImage);
        holder.tvFullName = (TextView) convertView.findViewById(R.id.tvName);
        holder.tvPhoneNumber = (TextView) convertView.findViewById(R.id.tvPhoneNo);
        holder.button = (Button) convertView.findViewById(R.id.ivButton);
        convertView.setTag(holder)
    }
    else{
        holder = (Holder)convertView.getTag()
    } 

    holder.tvFullName.setText(Contact.get(i).get(0));
    holder.tvPhoneNumber.setText(Contact.get(i).get(1));

    Picasso.with(context)
                .load(Contact.get(i).get(2))
                .into(holder.ivPhoto);

    return convertView;
}

Listview - How do I do a smooth scroll to top from the 10th item?

See this answer.

Quote:

First call smothScrollToPositionFromTop(position) and then, when
scrolling has finished, call setSelection(position). The latter call
corrects the incomplete scrolling by jumping directly to the desired
position. Doing so the user still has the impression that it is being
animation-scrolled to this position.

How to smooth the movement of a list item at a specific position

Try this:

    @Override
    public void onScrollStateChanged(final AbsListView view, int scrollState) {
        if (scrollState == SCROLL_STATE_IDLE) {
            View firstView = view.getChildAt(0);
            Rect rect = new Rect(0, 0, firstView.getWidth(), firstView.getHeight());
            view.getChildVisibleRect(firstView, rect, null);
            int position = view.getFirstVisiblePosition();
            if (rect.height() < (firstView.getHeight() / 2)) {
                position++;
            }
            final int finalPosition = position;
            view.postDelayed(new Runnable() {
                @Override
                public void run() {
                    view.smoothScrollToPositionFromTop(finalPosition, 0, 500);
                }
            }, 1);
        }
    }

Updated:
Above code has a constant settling time (500ms). Below code has a constant snap speed (0.2 pixel/ms, it means scroll up/down a pixel takes 5ms).

    final static int SCROLL_TIME_PER_PIXEL = 5; // Time(ms) to snap a pixel.
    @Override
    public void onScrollStateChanged(final AbsListView view, int scrollState) {
        if (scrollState == SCROLL_STATE_IDLE) {
            View firstView = view.getChildAt(0);
            Rect rect = new Rect(0, 0, firstView.getWidth(), firstView.getHeight());
            view.getChildVisibleRect(firstView, rect, null);
            int position = view.getFirstVisiblePosition();
            int offset = rect.height();
            if (rect.height() < (firstView.getHeight() / 2)) {
                position++;
            } else offset = firstView.getHeight() - rect.height();
            final int finalPosition = position; // Snap to position.
            final int finalOffset = offset; // Snap distance in pixels.
            view.postDelayed(new Runnable() {
                @Override
                public void run() {
                    view.smoothScrollToPositionFromTop(finalPosition, 0, finalOffset * SCROLL_TIME_PER_PIXEL);
                }
            }, 1);
        }
    }

Use Loader to load listview data in backgroud for smooth scrolling

To improve speed of your listview your must complete next steps:

1. Use ViewHolder patter because view.findViewById is slow operation.

2. You can load all needed typeface before. Your every time load same typefaces. For example Typeface.createFromAsset(context.getAssets(), "Roboto_Light.ttf")

3. You can load all zodiac icon before because i think that zodiac icon has limit count

4. if photo is big image than you can load image from another thread.

I think it is enough.

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