Custom listview scrollin isn't smooth

Question

I've created a custom listview which is working great apart from the fact that the list doesn't smooth scroll. Its choppy and slow.

Here's the code where I populate the listview:

@Override public View getView(int position, View convertView, ViewGroup parent) { View v = convertView; if (v == null) { LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE); v = vi.inflate(R.layout.listitem, null); } FilmRecord film = films.get(position); if (film != null) { TextView filmTitle = (TextView) v.findViewById(R.id.filmtitle); TextView filmShowingDate = (TextView) v.findViewById(R.id.filmshowingtime); TextView filmAdded = (TextView) v.findViewById(R.id.filmadded); TextView filmLocations = (TextView) v.findViewById(R.id.filmlocations); TextView filmDescription = (TextView) v.findViewById(R.id.filmdescription); TextView filmProvider = (TextView) v.findViewById(R.id.filmprovider); TextView filmTicketUrl = (TextView) v.findViewById(R.id.filmticketurl); if (filmTitle != null) { filmTitle.setText(film.filmTitle); } if(filmDescription != null) { filmDescription.setText(film.filmDescription ); } if(filmLocations != null) { filmLocations.setText(film.filmLocations ); } if(filmShowingDate != null) { filmShowingDate.setText("Showing: " + film.filmShowingDate ); } if(filmAdded != null) { filmAdded.setText("Added on: " + film.filmAdded ); } if(filmProvider != null) { filmProvider.setText(film.filmProvider ); } if(filmTicketUrl != null) { filmTicketUrl.setText(film.filmTicketUrl ); } } //Check who the provider is and set the imageview to provider logo ImageView imageView = (ImageView) v.findViewById(R.id.providerImage); if(film.filmProvider.equals("Cineworld")) { Log.d("Provider", "Provider is Cineworld"); imageView.setImageResource(R.drawable.cineworld); } else if(film.filmProvider.equals("Show Film Fist")){ Log.d("Provider", "Provider is Show Film Fist"); imageView.setImageResource(R.drawable.show_film_first); } return v; }

Has anyone had similar issues when creating a custom listview? Any help as always would be much appreciated :)

You need to change your logic. You are checking each fields for null, I think it will not give any error, when you will set text without checking null. And there must be two if for Showing: and Added on:. but you can remove these two if also by setting those two pre_text in your POJO. Hope it will clear. — Pankaj Kumar
– Pankaj Kumar, Commented Feb 20, 2012 at 10:15

Adil Soomro · Accepted Answer · 2012-02-20 10:27:01Z

You need to use ViewHolder approach.

because finding the View by id also takes time to execute.

by using ViewHolder approach you will be able to minimize the load created during finding View by id by caching the views :)

Here is nice tutorial how to do that.

Edit:

What ViewHolder approach do is:

Say you have 4 visible items in your ListView at a time. You have to inflate the View 4 time and findViewById() 4 times only even if you scroll to 1000th item in ListView.

But if you don't use ViewHolder and you have put

if (v == null) { LayoutInflater vi = ...; }else{ //... other implementation }

You have to inflate the View 4 time only, but findViewById() will be called every time when the getView() is called (usually when ListView is scrolled).

Happy coding!

Thanks again fo the tutorial. I've implemented the code accordingly. As soon as I scoll down the list, I get repeated list items. E.g. row 5 and 6 have the same content as row 0. Any ideas where I'm going wrong?
Hi Adil, thanks for replying :) I've be tweaking the code and it doesn't repeat list items. But now I'm back to the situation where I doesn't scroll smooth lol getView() code is at Pastie
the updated code worked. Many thanks for helping me out :) and thanks for the pastie.org link. Handy site for comments.

evertvandenbruel · Accepted Answer · 2012-07-20 11:40:18Z

I had the same problem today and while using the viewHolder pattern the scrolling was still laggy, until I wanted to show the problem to a colleague and noticed that scrolling was smooth. So the problem in my case was that I was connected to the debugger and that slowed things down.

Community · Accepted Answer · 2017-05-23 12:20:03Z

Please refer this question and see my answer there.It shows how you should declare your components in your custom adapter class.Making these changes to your class will definitely solve your problem as the question i suggested here also had the similar issue as yours:Scrolable ListView with costumized BaseAdapter is very slow

ramdroid · Accepted Answer · 2012-02-20 10:12:16Z

What are you doing in films.get(position)?

If you are reading from a database then your scrolling might really be bad here...

When using a database you should load the data into the adapter during onCreate, probably something like that (but with your previous listview layout etc.)

@Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); List<FilmRecord> values = films.getAllFilms(); ArrayAdapter<FilmRecord> adapter = new ArrayAdapter<FilmRecord>(this, your_list_item_layout_id, values); your_list_view.setListAdapter(adapter); }

In the getView() method you just have to ask the adapter:

FilmRecord film = getItem(position);

Yeah i'm reading from a database. How should I go about avoiding this issue then?
Hi ramdroid. I've modified the code as suggested with the addition of @Adil's suggestion which uses ViewHolder. Both of which have been excellent improvements on the code. But with these changes I have another issue. As soon as I scoll down the list, I get repeated list items. E.g. row 5 and 6 have the same content as row 0. Any ideas where I'm going wrong?

SAndroidD · Accepted Answer · 2014-03-21 12:20:13Z

check this link http://www.javacodegeeks.com/2012/06/android-smooth-list-scrolling.html

and also add this in Activity OnCreate() method

protected void onCreate(Bundle savedInstanceState) { //StrictMode for smooth list scroll StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder().detectDiskReads().detectDiskWrites().detectNetwork().penaltyLog().build()); super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); /*----- ListView Custom Adapter set data.... ------*/

}

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