Develop Reference

java.lang.NullPointerException: Attempt to read from field 'android.widget.TextView

Hello I realize there are multiple people with a similar issue but the reason for me adding this as a new question is because this is an adapter with two holders. I have a listview that has a header cell and the information cell. the error that I am encountering its
java.lang.NullPointerException: Attempt to read from field 'android.widget.TextView.
Which only happens when I scroll the list down and then go back up. I am assuming the holder is getting destroyed and when I call the line to add text the holder is null but I am not sure. Thank you for your help in advance!
Custom Adapter:
private class MyCustomAdapter extends ArrayAdapter<sources> {
private ArrayList<sources> sources_list = new ArrayList<sources>();
private TreeSet<Integer> sectionHeader = new TreeSet<Integer>();
private static final int TYPE_ITEM = 0;
private static final int TYPE_SEPARATOR = 1;
private LayoutInflater vi;
public MyCustomAdapter(Context context, int textViewResourceId, ArrayList<sources> sources_list) {
super(context, textViewResourceId, sources_list);
vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public void addItem(final sources item) {
sources_list.add(item);
notifyDataSetChanged();
}
public void addSectionHeaderItem(final sources item) {
sources_list.add(item);
sectionHeader.add(sources_list.size() - 1);
notifyDataSetChanged();
}
public int getItemViewType(int position) {
return sectionHeader.contains(position) ? TYPE_SEPARATOR : TYPE_ITEM;
}
public int getCount() {
return sources_list.size();
}
public int getViewTypeCount() {
return 2;
}
public sources getItem(int position) {
return sources_list.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
public class ViewHolder {
TextView code;
CheckBox name;
}
public class ViewHolder2 {
TextView separator;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
ViewHolder2 holder2 = null;
Log.v("ConvertView", String.valueOf(position));
int rowType = getItemViewType(position);
if (convertView == null) {
switch (rowType) {
case TYPE_ITEM:
convertView = vi.inflate(R.layout.source_cell, null);
holder = new ViewHolder();
holder.code = (TextView)
convertView.findViewById(R.id.code);
holder.name = (CheckBox)
convertView.findViewById(R.id.checkBox1);
break;
case TYPE_SEPARATOR:
holder2 = new ViewHolder2();
convertView = vi.inflate(R.layout.source_header, null);
holder2.separator = (TextView)
convertView.findViewById(R.id.separator);
break;
}
convertView.setTag(holder);
} else {
if (rowType == TYPE_ITEM) {
holder = (ViewHolder)
convertView.getTag(R.layout.source_cell);
} else {
holder2 = (ViewHolder2) convertView.getTag(R.layout.source_header);
}
}
if (rowType == TYPE_ITEM) {
sources n_source = sources_list.get(position);
holder.code.setText(n_source.getCode().toUpperCase());
holder.name.setTag(n_source);
} else {
sources n_source = sources_list.get(position);
holder2.separator.setText(n_source.getCode().toUpperCase());
}
return convertView;
}
}

Your setTag/getTag appears to be wrong. You need to use setTag(r.layout.blah, holder) to match your getTag(r.layout.blah).

ListView with section headers repeats items when scrolling

I have finally had some luck getting section headers to appear by creating a switch block in my getView(). In doing so I have created a problem with my adapter because now my ListView repeats the top items over and over again. I have found other people with a similar problems, but they were solved by adding convertView.setTag(holder); I already have this, so I believe my problem is something with the way I have set up my switch block. Maybe a syntax problem that is causing things not to line up correctly.
Any help would be appreciated. Here is my adapter:
public class PlayerAdapter extends BaseAdapter {
private Context mContext;
private static final int TYPE_ITEM = 0;
private static final int TYPE_SEPARATOR = 1;
private ArrayList<Player> mPlayers = new ArrayList<>();
private TreeSet<Integer> sectionHeader = new TreeSet<>();
public PlayerAdapter(Context context, ArrayList<Player> players) {
mContext = context;
mPlayers = players;
}
public void addItem(final Player player) {
mPlayers.add(player);
notifyDataSetChanged();
}
public void addSectionHeaderItem(final Player player) {
mPlayers.add(player);
sectionHeader.add(mPlayers.size() -1);
notifyDataSetChanged();
}
#Override
public int getItemViewType(int position) {
return sectionHeader.contains(position) ? TYPE_SEPARATOR : TYPE_ITEM;
}
#Override
public int getViewTypeCount() {
return 2;
}
#Override
public int getCount() {
return mPlayers.size();
}
#Override
public Object getItem(int position) {
return mPlayers.get(position);
}
#Override
public long getItemId(int position) {
return 0;
}
#Override
public boolean isEnabled(int position) {
int rowType = getItemViewType(position);
if(rowType == TYPE_SEPARATOR) {
return false;
}
return true;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = new ViewHolder();
int rowType = getItemViewType(position);
if (convertView == null) {
Player player = mPlayers.get(position);
switch (rowType){
case TYPE_ITEM:
convertView = LayoutInflater.from(mContext).inflate(R.layout.player_list_item_layout, null);
holder.playerNameTextView = (TextView) convertView.findViewById(R.id.playerNameTextView);
holder.playerValueTextView = (TextView) convertView.findViewById(R.id.playerValueTextView);
holder.remainingCapTextView = (TextView) convertView.findViewById(R.id.remainingCapTextView);
holder.username = (TextView) convertView.findViewById(R.id.opponentUsername);
holder.status = (TextView) convertView.findViewById(R.id.statusTextView);
holder.vsTeamAbbrev = (TextView) convertView.findViewById(R.id.vsTeam);
holder.resultsTextView = (TextView) convertView.findViewById(R.id.resultsTextView);
DecimalFormat formatter = new DecimalFormat("$#,###");
holder.playerNameTextView.setText(player.getName());
holder.playerValueTextView.setText(formatter.format(Double.parseDouble(player.getValue())));
holder.remainingCapTextView.setText(formatter.format(Double.parseDouble(player.getCap())));
holder.username.setText(player.getUsername());
holder.status.setText(player.getStatus());
holder.vsTeamAbbrev.setText(player.getVsTeamAbbrev());
holder.resultsTextView.setText(player.getResultsTextView());
if (player.isMatchMade()) {
holder.status.setVisibility(View.VISIBLE);
}
convertView.setTag(holder);
break;
case TYPE_SEPARATOR:
convertView = LayoutInflater.from(mContext).inflate(R.layout.player_section_header, null);
holder.playerNameTextView = (TextView) convertView.findViewById(R.id.lastPlayer);
holder.lastPlayerDate = (TextView) convertView.findViewById(R.id.lastPlayerDate);
holder.playerNameTextView.setText(player.getName());
holder.lastPlayerDate.setText(player.getLastPlayerDate());
convertView.setTag(holder);
break;
}
} else {
holder = (ViewHolder) convertView.getTag();
}
return convertView;
}
private static class ViewHolder {
//item views
TextView playerValueTextView;
TextView playerNameTextView;
TextView remainingCapTextView;
TextView username;
TextView status;
TextView vsTeamAbbrev;
TextView resultsTextView;
//section header views
TextView lastPlayer;
TextView lastPlayerDate;
}
}

This turned out to be a pretty simple mistake. I had to move the code that populates my views down below the else clause. This way if convert view is not null, it can still gettag() and populate the data.
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = new ViewHolder();
Player player = mPlayers.get(position);
int rowType = getItemViewType(position);
if (convertView == null) {
switch (rowType){
case TYPE_ITEM:
convertView = LayoutInflater.from(mContext).inflate(R.layout.player_list_item_layout, null);
holder.playerNameTextView = (TextView) convertView.findViewById(R.id.playerNameTextView);
holder.playerValueTextView = (TextView) convertView.findViewById(R.id.playerValueTextView);
holder.remainingCapTextView = (TextView) convertView.findViewById(R.id.remainingCapTextView);
holder.username = (TextView) convertView.findViewById(R.id.opponentUsername);
holder.status = (TextView) convertView.findViewById(R.id.statusTextView);
holder.vsTeamAbbrev = (TextView) convertView.findViewById(R.id.vsTeam);
holder.resultsTextView = (TextView) convertView.findViewById(R.id.resultsTextView);
convertView.setTag(holder);
break;
case TYPE_SEPARATOR:
convertView = LayoutInflater.from(mContext).inflate(R.layout.player_section_header, null);
holder.playerNameTextView = (TextView) convertView.findViewById(R.id.lastPlayer);
holder.lastPlayerDate = (TextView) convertView.findViewById(R.id.lastPlayerDate);
convertView.setTag(holder);
break;
}
//convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
switch (rowType){
case TYPE_ITEM:
DecimalFormat formatter = new DecimalFormat("$#,###");
holder.playerNameTextView.setText(player.getName());
holder.playerValueTextView.setText(formatter.format(Double.parseDouble(player.getValue())));
holder.remainingCapTextView.setText(formatter.format(Double.parseDouble(player.getCap())));
holder.username.setText(player.getUsername());
holder.status.setText(player.getStatus());
holder.vsTeamAbbrev.setText(player.getVsTeamAbbrev());
holder.resultsTextView.setText(player.getResultsTextView());
if (player.isMatchMade()) {
holder.status.setVisibility(View.VISIBLE);
}
break;
case TYPE_SEPARATOR:
holder.playerNameTextView.setText(player.getName());
holder.lastPlayerDate.setText(player.getLastPlayerDate());
break;
}
return convertView;
}
private static class ViewHolder {
//item views
TextView playerValueTextView;
TextView playerNameTextView;
TextView remainingCapTextView;
TextView username;
TextView status;
TextView vsTeamAbbrev;
TextView resultsTextView;
//section header views
TextView lastPlayer;
TextView lastPlayerDate;
}
}

adding separators in a listView

I'm trying to add separators between my list view items, I have sorted them into date order and added list entries where the separator needs to go but as soon as it gets to a seperator it stops, no error message or anything it just doesn't add the seperator. I've added breakpoints and it definitely runs the code to add it but it doesn't show up. Even if there are other items to add after the separator it still stops at the separator.
code:
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater itemInflater = LayoutInflater.from(getContext());
JourneyItem singleItem = list.get(position);
if(singleItem.isSeperator()){
//set customRow to seperator layout
View customRow = itemInflater.inflate(R.layout.journey_list_seperator, parent, false);
TextView monthText = (TextView) customRow.findViewById(R.id.seperatorMonthText);
TextView yearText = (TextView) customRow.findViewById(R.id.seperatorYearText);
Date current = new Date();
SimpleDateFormat df = new SimpleDateFormat("dd/MM/yyyy");
String dtp = GeneralUtil.SQLDateFormatToHuman(list.get(position).getDepartDateTime());
try {
current = df.parse(dtp);
} catch (ParseException e) {
e.printStackTrace();
}
SimpleDateFormat sdfDate = new SimpleDateFormat("MMMM");
monthText.setText(sdfDate.format(current));
yearText.setText(list.get(position).getDepartDateTime().substring(6,10));
return customRow;
}else {
View customRow = itemInflater.inflate(R.layout.custom_journeyitem_row, parent, false);
TextView titleText = (TextView) customRow.findViewById(R.id.titleDisplay);
TextView fromText = (TextView) customRow.findViewById(R.id.fromLocationDisplay);
TextView departText = (TextView) customRow.findViewById(R.id.departDateTimeDisplay);
TextView toText = (TextView) customRow.findViewById(R.id.toLocationDisplay);
TextView colourLbl = (TextView) customRow.findViewById(R.id.colourDisplay);
titleText.setText(singleItem.getTitle());
fromText.setText("From: " + singleItem.getFromLocation());
departText.setText(singleItem.getDepartDateTime());
toText.setText("To: " + singleItem.getToLocation());
colourLbl.setBackgroundColor(singleItem.getColourCode());
return customRow;
}

Create Coustom adapter like this.
class CustomAdapter extends BaseAdapter {
private static final int TYPE_ITEM = 0;
private static final int TYPE_SEPARATOR = 1;
private ArrayList<String> mData = new ArrayList<String>();
private TreeSet<Integer> sectionHeader = new TreeSet<Integer>();
private LayoutInflater mInflater;
public CustomAdapter(Context context) {
mInflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public void addItem(final String item) {
mData.add(item);
notifyDataSetChanged();
}
public void addSectionHeaderItem(final String item) {
mData.add(item);
sectionHeader.add(mData.size() - 1);
notifyDataSetChanged();
}
#Override
public int getItemViewType(int position) {
return sectionHeader.contains(position) ? TYPE_SEPARATOR : TYPE_ITEM;
}
#Override
public int getViewTypeCount() {
return 2;
}
#Override
public int getCount() {
return mData.size();
}
#Override
public String getItem(int position) {
return mData.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
int rowType = getItemViewType(position);
if (convertView == null) {
holder = new ViewHolder();
switch (rowType) {
case TYPE_ITEM:
convertView = mInflater.inflate(R.layout.snippet_item1, null);
holder.textView = (TextView) convertView.findViewById(R.id.text);
break;
case TYPE_SEPARATOR:
convertView = mInflater.inflate(R.layout.snippet_item2, null);
holder.textView = (TextView) convertView.findViewById(R.id.textSeparator);
break;
}
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.textView.setText(mData.get(position));
return convertView;
}
public static class ViewHolder {
public TextView textView;
}
}
Complete link here.

How to deal with an array item from a spinner?

I need a code to deal with an item in array inside a spinner to allow me to check
.....
if(item == "item name"){
do something
}
or
if(item.position == 1){
do something
}

You can change in adapter like this code
public class PlannedRideAdapter extends BaseAdapter {
// private LayoutInflater mInflater;
private Context context;
private RideData rideData = new RideData();
private List<RideData> ride_data;
public PlannedRideAdapter(Context context, List<RideData> ridedata) {
this.context = context;
this.ride_data = ridedata;
}
#Override
public int getCount() {
if (ride_data.size() > 0) {
return ride_data.size();
}
return 1;
}
#Override
public Object getItem(int arg0) {
return arg0;
}
#Override
public long getItemId(int arg0) {
return arg0;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewholder;
if (convertView == null) {
LayoutInflater inflator = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflator.inflate(R.layout.plannedride_km_list, null);
viewholder = new ViewHolder();
convertView.setTag(viewholder);
} else {
viewholder = (ViewHolder) convertView.getTag();
}
rideData = ride_data.get(position);
// init view
viewholder.imageView = (ImageView) convertView
.findViewById(R.id.imageView1);
viewholder.date = (TextView) convertView.findViewById(R.id.date_value);
viewholder.source = (CustomFontTextView) convertView
.findViewById(R.id.source_icon);
viewholder.time = (TextView) convertView.findViewById(R.id.time_value);
viewholder.destination = (CustomFontTextView) convertView
.findViewById(R.id.dest_icon);
viewholder.rideId = (CustomFontTextView) convertView
.findViewById(R.id.rideId);
viewholder.ride_id = (TextView) convertView
.findViewById(R.id.rideIdText);
viewholder.distance = (CustomFontTextView) convertView
.findViewById(R.id.distance);
viewholder.source_value = (TextView) convertView
.findViewById(R.id.source_value);
viewholder.ride_id_value = (TextView) convertView
.findViewById(R.id.rideId_value);
viewholder.distance_value = (TextView) convertView
.findViewById(R.id.distance_value);
// viewholder.ride_detail = (TextView) convertView
// .findViewById(R.id.textRideDetail);
// setview
viewholder.date.setText("" + rideData.getDate());
viewholder.source.setText(context.getResources().getString(
R.string.font_awesome_marker_icon));
viewholder.source_value.setText("" + rideData.getSource());
viewholder.time.setText("" + rideData.getTime());
viewholder.rideId.setText(context.getResources().getString(
R.string.font_awesome_bookingnumber_icon));
viewholder.ride_id_value.setText("" + rideData.getRideId());
if (rideData.getRideType().equalsIgnoreCase("k")) {
viewholder.distance.setVisibility(View.VISIBLE);
viewholder.distance_value.setVisibility(View.VISIBLE);
viewholder.imageView.setImageResource((R.drawable.one_way));
viewholder.destination.setText(context.getResources().getString(
R.string.font_awesome_radio_tick_icon));
viewholder.distance.setText(context.getResources().getString(
R.string.font_awesome_distance_icon));
viewholder.distance_value.setText(""
+ rideData.getKilometerRide().getDestination());
} else {
viewholder.imageView.setImageResource((R.drawable.time));
viewholder.destination.setText(context.getResources().getString(
R.string.font_awesome_clock_icon));
viewholder.distance.setVisibility(View.GONE);
viewholder.distance_value.setVisibility(View.GONE);
// viewholder.ride_detail.setVisibility(View.GONE);
}
return convertView;
}
public List<RideData> getRide_data() {
return ride_data;
}
public void setRide_data(List<RideData> ride_data) {
this.ride_data = ride_data;
}
public static class ViewHolder {
public CustomFontTextView source;
public CustomFontTextView destination;
public CustomFontTextView rideId;
public CustomFontTextView distance;
public CustomFontTextView total_time;
public TextView date, time, distance_value, source_value,
destination_value, time_value, ride_id_value, ride_id;
public ImageView imageView;
}
}
I am showing list based on kilometer(rideType k) or hourly (rideType h) with same layout.

Android Image not loaded in Custom Adapter

I am having list of my Facebook friends and i created a list View that's having separator as months from Jan to Dec.
I am able list my friends details, My problem is that i am able to show their Name and birthday date if i try load their "PICTURES" i can't do it..
It showing me the icon set as Background in XML.
Even the URL for the image to be load is get printed in Log, but i cant get the image..
Here is my code
private class MyCustomAdapter extends BaseAdapter {
private static final int TYPE_ITEM = 0;
private static final int TYPE_SEPARATOR = 1;
private static final int TYPE_MAX_COUNT = TYPE_SEPARATOR + 1;
private LayoutInflater mInflater;
private TreeSet<Integer> mSeparatorsSet = new TreeSet<Integer>();
public MyCustomAdapter() {
mInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
mData = new ArrayList<Category>();
}
public void addItem(final Category item) {
mData.add(item);
notifyDataSetChanged();
}
public void addSeparatorItem(final Category item) {
mData.add(item);
// save separator position
mSeparatorsSet.add(mData.size() - 1);
notifyDataSetChanged();
}
#Override
public int getItemViewType(int position) {
return mSeparatorsSet.contains(position) ? TYPE_SEPARATOR : TYPE_ITEM;
}
#Override
public int getViewTypeCount() {
return TYPE_MAX_COUNT;
}
#Override
public int getCount() {
return mData.size();
}
#Override
public Category getItem(int position) {
return mData.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
int type = getItemViewType(position);
System.out.println("getView " + position + " " + convertView + " type = " + type);
Category category = mData.get(position);
holder = new ViewHolder();
if (convertView == null) {
switch (type) {
case TYPE_ITEM:
convertView = mInflater.inflate(R.layout.item1, null);
holder.textView = (TextView)convertView.findViewById(R.id.text);
holder.textView1 = (TextView)convertView.findViewById(R.id.text1);
holder.icon = (ImageView) convertView.findViewById(R.id.friend_photo);
break;
case TYPE_SEPARATOR:
convertView = mInflater.inflate(R.layout.item2, null);
holder.textView = (TextView)convertView.findViewById(R.id.textSeparator);
break;
}
convertView.setTag(holder);
} else {
if(type==TYPE_ITEM){
holder.textView = (TextView)convertView.findViewById(R.id.text);
holder.textView1 = (TextView)convertView.findViewById(R.id.text1);
holder.icon = (ImageView) convertView.findViewById(R.id.friend_photo);
holder = (ViewHolder)convertView.getTag();
}else{
holder.textView = (TextView)convertView.findViewById(R.id.textSeparator);
holder = (ViewHolder)convertView.getTag();
}
}
if(type==TYPE_SEPARATOR){
holder.textView.setText(mData.get(position).dealTitle);
}else{
holder.textView.setText(mData.get(position).dealTitle);
holder.textView1.setText(mData.get(position).dealDesc);
holder.icon.setTag(mData.get(position).picture);
}
return convertView;
}
}

You need to set your ImageView's bitmap using one of the setImageFoo() calls.
setImageResource()
setImageBitmap()
setImageDrawable()

I'm not sure what type of object mData.get(position).picture is but
holder.icon.setTag(mData.get(position).picture);
isn't loading the picture. That's just setting some data on the View.
You need to use one of the setImage() methods of ImageView.

Your code looks fine, there might be a problem with the xml/layout file.
As you are loading two textViews and a ImageView from the xml for each item, it is important to know how the layout is organised to show all the added views in it.
Please post the layout files so that, one can suggest if there is any problem.