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Listview lag when scrolling, and crash when add item

I have a custom listview with a button to add more elements
but when I add and element the app crash, but when I restart I find that the element is added, (rarely it doesn't crash)
And i
I use custom adapter
class CustomAdapter extends BaseAdapter {
ArrayList<ListItem> listItems = new ArrayList<ListItem>();
CustomAdapter(ArrayList<ListItem> list){
this.listItems = list;
}
#Override
public int getCount() {
return listItems.size();
}
#Override
public Object getItem(int position) {
return listItems.get(position).name;
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int i, View convertView, ViewGroup parent) {
LayoutInflater inflater = getLayoutInflater();
View view = inflater.inflate(R.layout.list_item,null);
TextView name = (TextView) view.findViewById(R.id.name);
TextView lastm = (TextView) view.findViewById(R.id.last);
TextView time = (TextView) view.findViewById(R.id.time);
CircleImageView pic= (CircleImageView) view.findViewById(R.id.pic);
name.setText(listItems.get(i).name);
lastm.setText(listItems.get(i).lastm);
time.setText(listItems.get(i).time);
Bitmap bmp = BitmapFactory.decodeByteArray(listItems.get(i).pic,0,listItems.get(i).pic.length);
pic.setImageBitmap(bmp);
return view;
}
}
and when I add an element the app crashs
add.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
EditText editText=(EditText) mView.findViewById(R.id.name);
String name=editText.getText().toString();
boolean result=myDataBase.insertData(imageViewToByte(img),name,"no messages yet","");
if (result) {
Toast.makeText(Main2Activity.this, "Saved in DATABASE", Toast.LENGTH_SHORT).show();
viewLastData();
dialog.dismiss();
}

If your ListView lags it's because you used wrap_content for the listView's layout_height. It forces your ListView to count all the items inside and it has a huge performance impact.
So replace wrap_content by match_parent to avoid those lags.
EDIT: Use a ViewHolder pattern too in your Adapter, see this link.
Here is an example:
// ViewHolder Pattern
private static class ViewHolder {
TextView name, status;
}
#Override #NonNull
public View getView(int position, View convertView, #NonNull ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
LayoutInflater vi = LayoutInflater.from(getContext());
convertView = vi.inflate(R.layout.list_item, parent, false);
holder = new ViewHolder();
holder.name = (TextView) convertView.findViewById(R.id.text_name);
holder.status = (TextView) convertView.findViewById(R.id.another_text);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
// Then do the other stuff with your item
// to populate your listView
// ...
return convertView
}

Android Listview clickable textview

I have made an Listview populated with list_row_layout.xml(which is populated with json serializable class), i have clickable textview and onclick changing text from "Accept" to "Accepted". But when i click it on first listview item, another textview listview items below are changing.
Here's some photos to descibe you better
this is the adapter class
public class CustomListAdapter extends BaseAdapter {
private ArrayList<FeedItem> listData;
private LayoutInflater layoutInflater;
private Context mContext;
public CustomListAdapter(Context context, ArrayList<FeedItem> listData) {
this.listData = listData;
layoutInflater = LayoutInflater.from(context);
mContext = context;
}
#Override
public int getCount() {
return listData.size();
}
#Override
public Object getItem(int position) {
return listData.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
final ViewHolder holder;
if (convertView == null) {
convertView = layoutInflater.inflate(R.layout.list_row_layout, null);
holder = new ViewHolder();
holder.headlineView = (TextView)convertView.findViewById(R.id.sex);
holder.reportedDateView = (TextView) convertView.findViewById(R.id.confid);
holder.approve = (TextView) convertView.findViewById(R.id.approveTV);
holder.approve.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View argView)
{
holder.approve.setText("Accepted");
}
}
);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
FeedItem newsItem = (FeedItem) listData.get(position);
holder.headlineView.setText(Html.fromHtml(newsItem.getTitle()));
holder.reportedDateView.setText(Html.fromHtml(newsItem.getContent()));
return convertView;
}
static class ViewHolder {
TextView approve;
TextView headlineView;
TextView reportedDateView;
ImageView imageView;
}
}

Remember that views can be recycled via convertView.
In your onClick method you set the approve text to "Accepted" but when the view is recycled, you never set it back to "Accept"
Actually you need to update (something in) the list in response to an click and have the Accept/Accepted value toggle based on that value rather than simply updating what is currently visible on the screen.
-- to answer the "how" question (asked below)--
Add a new field to ViewHolder
static class ViewHolder {
TextView approve;
TextView headlineView;
TextView reportedDateView;
ImageView imageView;
FeedItem newsItem;
}
Change the onClick method:
public void onClick(View argView)
{
// note that holder no longer needs to be final in the parent class
// because it is not used here.
View parent = (View)argView.getParent();
ViewHolder clickedHolder = (ViewHolder)parent.getTag();
clickedHolder .newsItem.setAccepted(true); /// a new method
clickedHolder .approve.setText ("Accepted");
Log.d(TAG, "Accepted item #" + position);
}
After you have convertView created (if necessary)
FeedItem newsItem = (FeedItem) listData.get(position);
holder.newsItem = newsItem; // populate the new field.
holder.headlineView.setText(Html.fromHtml(newsItem.getTitle()));
holder.reportedDateView.setText(Html.fromHtml(newsItem.getContent()));
if(newsItem.isAccepted ()){ // another new method!
holder.approve.setText ("Accepted");
Log.d(TAG, "Set text to Accepted for item #" + position);
}else{
holder.approve.setText("Accept");
Log.d(TAG, "Set text to Accept for item #" + position);
}
Once it is working you should consider removing the Log.d() lines to cut down on the noise in LogCat.

my images get shuffled or changed when i scroll in list view

my images get shuffled or changed when i scroll in list view.......
Images get shuffled when i scroll down and keep on changing own its own...............
public class CustomListAdapter extends BaseAdapter {
private ArrayList<NewsItem> listData;
private LayoutInflater layoutInflater;
public CustomListAdapter(Context context, ArrayList<NewsItem> listData) {
this.listData = listData;
layoutInflater = LayoutInflater.from(context);
}
#Override
public int getCount() {
return listData.size();
}
#Override
public Object getItem(int position) {
return listData.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = layoutInflater.inflate(R.layout.activity_list_search, null);
holder = new ViewHolder();
holder.headlineView = (TextView) convertView.findViewById(R.id.title);
holder.reporterNameView = (TextView) convertView.findViewById(R.id.reporter);
holder.reportedDateView = (TextView) convertView.findViewById(R.id.date);
holder.imageView = (ImageView) convertView.findViewById(R.id.thumbImage);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
NewsItem newsItem = (NewsItem) listData.get(position);
holder.headlineView.setText(newsItem.getHeadline());
holder.reporterNameView.setText("Model: " + newsItem.getReporterName());
holder.reportedDateView.setText(newsItem.getDate());
if (holder.imageView != null) {
new ImageDownloaderTask(holder.imageView).execute(newsItem.getUrl());
}
return convertView;
}
static class ViewHolder {
TextView headlineView;
TextView reporterNameView;
TextView reportedDateView;
ImageView imageView;
}
}

The problem is very generic for new Android developers.
Your ImageDownloaderTask should take care of whether the downloaded image should still be posted on screen.
For example, after ImageDownloaderTask finishes one image downloading task (e.g. for index 15), it should make sure the 15th item is still displaying on screen. Since ListView is reusing all the item views, if you directly set the bit map to the original referenced view, your imageview will be shuffled.

Get ListItem position in custom SimpleLayout

I have a custom ListView with a TextView and a CheckBox. I also have a custom SimpleAdapter in which I override the getView() method and am able to retrieve clicks on the TextView and CheckBox changes. My problem is that I don't know how to get the correct clicked ListItem or CheckBox inside the OnCheckedChanged or OnClick.
UPDATE added whole CustomAdapter class:
public class CustomAdapter extends SimpleAdapter {
private LayoutInflater mInflater;
private List<HashMap<String, String>> mItems = null;
private Context mContext;
private int mPosicion;
public CustomAdapter(Context context, List<HashMap<String, String>> items, int resource, String[] from, int[] to) {
super(context, items, resource, from, to);
mInflater = LayoutInflater.from(context);
mItems = items;
mContext = context;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
mPosicion = position;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.custom_row_view, null);
holder = new ViewHolder();
holder.chkbxEstado = (CheckBox) convertView.findViewById(R.id.chkbxCompletado);
holder.txtTextoAgenda = (TextView) convertView.findViewById(R.id.txtTextoLista);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.txtTextoAgenda.setText(mItems.get(position).get("descripcion"));
convertView.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Log.i("Posicion",""+mPosicion);//I don't know how to retrieve clicked position
}
});
holder.chkbxEstado.setOnCheckedChangeListener(new OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
Log.i("Posicion",""+mPosicion);//Or checked
}
});
return convertView;
}
private static class ViewHolder {
TextView txtTextoAgenda;
CheckBox chkbxEstado;
}
}
Any help is appreciated.

I found a solution. If anybody knows a better one, please let me know. Working CustomAdapter class:
public class CustomAdapter extends SimpleAdapter {
private LayoutInflater mInflater;
private List<HashMap<String, String>> mItems = null;
private Context mContext;
private OnClickListener mClick;
private OnCheckedChangeListener mChecked;
public CustomAdapter(Context context, List<HashMap<String, String>> items, int resource, String[] from, int[] to) {
super(context, items, resource, from, to);
mInflater = LayoutInflater.from(context);
mItems = items;
mContext = context;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.custom_row_view, null);
holder = new ViewHolder();
holder.chkbxEstado = (CheckBox) convertView.findViewById(R.id.chkbxCompletado);
holder.txtTextoAgenda = (TextView) convertView.findViewById(R.id.txtTextoLista);
holder.posicion = position; //Add the new position into the holder for each row.
convertView.setTag(holder);
mClick = new OnClickListener() {
#Override
public void onClick(View v) {
ViewHolder viewHolder = getViewHolder(v); //Get the ViewHolder for the clicked row.
Log.i("Posicion",""+v.posicion);
}
};
mChecked = new OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
ViewHolder viewHolder = getViewHolder(buttonView); //Get the ViewHolder for the clicked CheckBox
Log.i("Posicion",""+viewHolder.posicion);
}
};
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.txtTextoAgenda.setText(mItems.get(position).get("descripcion"));
convertView.setOnClickListener(mClick);
holder.chkbxEstado.setOnCheckedChangeListener(mChecked);
return convertView;
}
public ViewHolder getViewHolder(View v){ //This method returns the ViewHolder stored in the tag if available, if not it recursively checks the parent's tag.
if(v.getTag() == null){
return getViewHolder((View)v.getParent());
}
return (ViewHolder)v.getTag();
}
private static class ViewHolder {
TextView txtTextoAgenda;
CheckBox chkbxEstado;
int posicion; //Added position attribute to ViewHolder class.
}
}
Edited to re-use onClickListener() and onCheckedChangedListener() instances.

The OP's solution works. But if you are extending a CursorAdapter, the position parameter does not exist in newView() and bindView(). What to do?
They do supply a Cursor. Use cursor.getPosition(). It does the same thing.

How to get view for an item in listview in android?

Is it possible to get an item view based on its position in the adapter and not in the visible views in the ListView?
I am aware of functions like getChildAt() and getItemIdAtPosition() however they provide information based on the visible views inside ListView. I am also aware that Android recycles views which means that I can only work with the visible views in the ListView.
My objective is to have a universal identifier for each item since I am using CursorAdapter so I don't have to calculate the item's position relative to the visible items.

Here's how I accomplished this. Within my (custom) adapter class:
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = null;
if (convertView == null) {
LayoutInflater inflater = context.getLayoutInflater();
view = inflater.inflate(textViewResourceId, parent, false);
final ViewHolder viewHolder = new ViewHolder();
viewHolder.name = (TextView) view.findViewById(R.id.name);
viewHolder.button = (ImageButton) view.findViewById(R.id.button);
viewHolder.button.setOnClickListener
(new View.OnClickListener() {
#Override
public void onClick(View view) {
int position = (int) viewHolder.button.getTag();
Log.d(TAG, "Position is: " +position);
}
});
view.setTag(viewHolder);
viewHolder.button.setTag(items.get(position));
} else {
view = convertView;
((ViewHolder) view.getTag()).button.setTag(items.get(position));
}
ViewHolder holder = (ViewHolder) view.getTag();
return view;
}
Essentially the trick is to set and retrieve the position index via the setTag and getTag methods. The items variable refers to the ArrayList containing my custom (adapter) objects.
Also see this tutorial for in-depth examples. Let me know if you need me to clarify anything.

See below code:
public static class ViewHolder
{
public TextView nm;
public TextView tnm;
public TextView tr;
public TextView re;
public TextView membercount;
public TextView membernm;
public TextView email;
public TextView phone;
public ImageView ii;
}
class ImageAdapter extends ArrayAdapter<CoordinatorData>
{
private ArrayList<CoordinatorData> items;
public FoodDriveImageLoader imageLoader;
public ImageAdapter(Context context, int textViewResourceId,ArrayList<CoordinatorData> items)
{
super(context, textViewResourceId, items);
this.items = items;
}
public View getView(int position, View convertView, ViewGroup parent)
{
View v = convertView;
ViewHolder holder = null;
if (v == null)
{
try
{
holder=new ViewHolder();
LayoutInflater vi = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
imageLoader = new FoodDriveImageLoader(FoodDriveModule.this);
v = vi.inflate(R.layout.virtual_food_drive_row, null);
//System.out.println("layout is null.......");
holder.nm = (TextView) v.findViewById(R.id.name);
holder.tnm = (TextView) v.findViewById(R.id.teamname);
holder.tr = (TextView) v.findViewById(R.id.target);
holder.re = (TextView) v.findViewById(R.id.received);
holder.membercount = new TextView(FoodDriveModule.this);
holder.membernm = new TextView(FoodDriveModule.this);
holder.email = new TextView(FoodDriveModule.this);
holder.phone = new TextView(FoodDriveModule.this);
holder.ii = (ImageView) v.findViewById(R.id.icon);
v.setTag(holder);
}
catch(Exception e)
{
System.out.println("Excption Caught"+e);
}
}
else
{
holder=(ViewHolder)v.getTag();
}
CoordinatorData co = items.get(position);
holder.nm.setText(co.getName());
holder.tnm.setText(co.getTeamName());
holder.tr.setText(co.getTarget());
holder.re.setText(co.getReceived());
holder.ii.setTag(co.getImage());
imageLoader.DisplayImage(co.getImage(), FoodDriveModule.this , holder.ii);
if (co != null)
{
}
return v;
}
}

A better option is to identify using the data returned by the CursorAdapter rather than visible views.
For example if your data is in a Array , each data item has a unique index.

Here, Its very short described code, you can simple re-use viewholder pattern to increase listview performance
Write below code in your getview() method
ViewHolder holder = new ViewHolder();
if (convertView == null) {
convertView = layoutInflater.inflate(R.layout.skateparklist, null);
holder = new ViewHolder();
holder.headlineView = (TextView) convertView
.findViewById(R.id.textView1);
holder.DistanceView = (TextView) convertView
.findViewById(R.id.textView2);
holder.imgview = (NetworkImageView) convertView
.findViewById(R.id.imgSkatepark);
convertView.setTag(holder); //PLEASE PASS HOLDER AS OBJECT PARAM , CAUSE YOU CAN NOY PASS POSITION IT WILL BE CONFLICT Holder and Integer can not cast
//BECAUSE WE NEED TO REUSE CREATED HOLDER
} else {
holder = (ViewHolder) convertView.getTag();
}
// your controls/UI setup
holder.DistanceView.setText(strDistance);
......
return convertview

Listview lv = (ListView) findViewById(R.id.previewlist);
final BaseAdapter adapter = new PreviewAdapter(this, name, age);
confirm.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
View view = null;
String value;
for (int i = 0; i < adapter.getCount(); i++) {
view = adapter.getView(i, view, lv);
Textview et = (TextView) view.findViewById(R.id.passfare);
value=et.getText().toString();
Toast.makeText(getApplicationContext(), value,
Toast.LENGTH_SHORT).show();
}
}
});