I have chat app In custom array adapter. I set random colors to usernames for each message with this code:
String[] array = context.getResources().getStringArray(R.array.username_colors);
randomColor = array[new Random().nextInt(array.length)];
nameTextView.setTextColor(Color.parseColor(randomColor));
When new message arrive I add it to listview, and call adapter.notifyDataSetChanged(); This causes recoloring existing usernames in messages each time. How can I prevent recoloring existing items in listview when calling adapter.notifyDataSetChanged();
Edit 1
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ChatMessageElement el = list.get(position);
ViewHolder holder = null;
NewMessagesLabelHolder labelHolder = null;
if (convertView == null) {
convertView = el.getView(inflater, parent);
if (el.isMessage()) {
holder = new ViewHolder();
holder.messageLayout = (RelativeLayout) convertView.findViewById(R.id.message_container);
holder.messageContent = (LinearLayout) convertView.findViewById(R.id.message_content);
holder.bottomIndicator = (LinearLayout) convertView.findViewById(R.id.bottom_indicators);
holder.dateTextView = (TextView) convertView.findViewById(R.id.message_date);
holder.timeAgo = (TextView) convertView.findViewById(R.id.time_ago);
holder.nameTextView = (TextView) convertView.findViewById(R.id.user_name);
holder.likesCountTextView = (TextView) convertView.findViewById(R.id.likes_count);
holder.likesLabelImageView = (ImageView) convertView.findViewById(R.id.likes_label);
holder.spamCountTextView = (TextView) convertView.findViewById(R.id.spam_count);
holder.spamLabelImageView = (ImageView) convertView.findViewById(R.id.spam_label);
holder.avatarImageView = (ImageView) convertView.findViewById(R.id.avatar);
holder.statusImageView = (ImageView) convertView.findViewById(R.id.delivered_label);
holder.progressBar = (ProgressBar) convertView.findViewById(R.id.progress_bar);
holder.errorSign = (ImageView) convertView.findViewById(R.id.error_sign);
holder.spamSign = (ImageView) convertView.findViewById(R.id.spam_sign);
holder.bookmarkLabel = (ImageView) convertView.findViewById(R.id.bookmark_label);
holder.topIndicators = (LinearLayout) convertView.findViewById(R.id.topIndicators);
convertView.setTag(holder);
}
if (el.isNewMessagesLabel()) {
convertView = inflater.inflate(R.layout.chat_new_messages_label_layout, parent, false);
labelHolder = new NewMessagesLabelHolder();
labelHolder.newMessagesLabel = (TextView) convertView.findViewById(R.id.new_messages_label);
convertView.setTag(labelHolder);
}
} else {
if (el.isMessage()) {
holder = (ViewHolder) convertView.getTag();
}
if (el.isNewMessagesLabel()) {
labelHolder = (NewMessagesLabelHolder) convertView.getTag();
}
}
if (el.isMessage()) {
Message currentMessage = (Message) el;
drawMessage(holder, currentMessage, position);
}
if (el.isNewMessagesLabel()) {
NewMessagesLabel messagesLabel = (NewMessagesLabel) el;
drawNewMessagesLabel(labelHolder, messagesLabel);
}
return convertView;
}
private void drawMessage(ViewHolder holder, Message message, int position) {
String date = message.getCreatedAt();
String formattedDate = DateHelper.getInstance(context).formatDate("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", "HH:mm", date);
String userName = message.getUserName();
holder.likesLabelImageView.setVisibility(View.GONE);
holder.likesCountTextView.setVisibility(View.GONE);
holder.spamCountTextView.setVisibility(View.GONE);
holder.spamLabelImageView.setVisibility(View.GONE);
holder.bookmarkLabel.setVisibility(View.GONE);
holder.statusImageView.setVisibility(View.GONE);
holder.progressBar.setVisibility(View.GONE);
holder.statusImageView.setVisibility(View.GONE);
holder.errorSign.setVisibility(View.GONE);
holder.spamSign.setVisibility(View.GONE);
holder.timeAgo.setVisibility(View.GONE);
holder.timeAgo.setText("");
holder.messageLayout.setAlpha(1f);
holder.topIndicators.setVisibility(View.VISIBLE);
if (message.isNewDay()) {
holder.timeAgo.setVisibility(View.VISIBLE);
String dayDate = DateHelper.getInstance(context).formatDate("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", "MMMM d, yyyy", date);
//String dayDate = getTimeAgo(mHelper.millisFromString(message.getCreatedAt()), context);
holder.timeAgo.setText(dayDate);
}else{
holder.timeAgo.setVisibility(View.GONE);
}
holder.avatarImageView.setImageResource(R.drawable.com_facebook_profile_default_icon);
if (GrouviDatabaseManager.getInstance(context).getCurrentUser().getId() == message.getUserId()) {
userName = USERNAME_ME;
if (message.getStatus() != null && message.getStatus().equals(Message.MSG_STATUS_SEND)) {
holder.statusImageView.setBackgroundResource(R.drawable.icon_chat_message_delivered);
holder.statusImageView.setVisibility(View.VISIBLE);
}
if (message.getStatus() != null && message.getStatus().equals(Message.MSG_STATUS_SENDING)) {
holder.progressBar.setVisibility(View.VISIBLE);
}
if (message.getStatus() != null && message.getStatus().equals(Message.MSG_STATUS_LOCAL)) {
holder.statusImageView.setBackgroundResource(R.drawable.icon_chat_message_delivered);
holder.statusImageView.setVisibility(View.VISIBLE);
}
if (message.getStatus() == null || message.getStatus().equals(Message.MSG_STATUS_ERROR)) {
holder.messageLayout.setAlpha(0.4f);
holder.errorSign.setVisibility(View.VISIBLE);
}
}
if (message.getSpamCount() > 0 && currentMode == MODE_NORMAL) {
holder.messageLayout.setAlpha(0.4f);
holder.spamSign.setVisibility(View.VISIBLE);
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
holder.messageContent.setLayoutParams(params);
holder.spamCountTextView.setText(Integer.toString(message.getSpamCount()));
holder.spamCountTextView.setVisibility(View.VISIBLE);
holder.spamLabelImageView.setVisibility(View.VISIBLE);
} else {
holder.messageLayout.setAlpha(1f);
holder.spamSign.setVisibility(View.GONE);
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
holder.messageContent.setLayoutParams(params);
}
if (currentMode == MODE_REPORT) {
String timeAgo = getTimeAgo(mHelper.millisFromString(message.getCreatedAt()));
holder.timeAgo.setText(timeAgo);
holder.timeAgo.setVisibility(View.VISIBLE);
}
if (message.getUserAvatar() != null && !message.getUserAvatar().isEmpty()) {
try {
Picasso
.with(context)
.load(message.getUserAvatar())
.error(R.drawable.com_facebook_profile_default_icon)
.placeholder(R.drawable.com_facebook_profile_default_icon)
.into(holder.avatarImageView);
} catch (Exception e) {
Log.e("Main", e.getMessage(), e);
}
}
colorUsername(holder, message, userName);
holder.nameTextView.setText(userName);
holder.dateTextView.setText(formattedDate);
if (message.getLikesCount()>0) {
holder.likesCountTextView.setText(Integer.toString(message.getLikesCount()));
holder.likesCountTextView.setVisibility(View.VISIBLE);
holder.likesLabelImageView.setVisibility(View.VISIBLE);
}
if (message.isBookmarked()) {
holder.bookmarkLabel.setVisibility(View.VISIBLE);
}
List<MessageComponent> messageComponentList;
messageComponentList = message.getMessageComponents();
drawMessageContent(holder, messageComponentList, message);
holder.nameTextView.setTag(position);
holder.avatarImageView.setTag(position);
holder.nameTextView.setOnClickListener(userClickListener);
holder.avatarImageView.setOnClickListener(userClickListener);
// hang empty onLingClickListener to display context menu when
// long click on whole message
holder.nameTextView.setOnLongClickListener(longClickListener);
holder.avatarImageView.setOnLongClickListener(longClickListener);
}
private void colorUsername(ViewHolder holder, Message message, String userName) {
String randomColor = prevColor;
if (userName.equals(USERNAME_ME)){
randomColor = "#000000";
}else if (message.getUserId()!=prevMsgUserID) {
do {
String[] array = context.getResources().getStringArray(R.array.username_colors);
randomColor = array[new Random().nextInt(array.length)];
}while (prevColor.equals(randomColor));
}
holder.nameTextView.setTextColor(Color.parseColor(randomColor));
prevColor = randomColor;
prevMsgUserID = message.getUserId();
}
You should keep color in the data class, for example in the Message class, or keep Map in the adapter, that maps Message to Color. Then randomly create a color, when it doesn't present in the map. or use the color, if it present in the map. Using a map is good solution than keeping in the data class, when the color doesn't related to message, when it is not a message property, so in that case, a good solution is a keeping it in the adapter class, in the map, for example
private Map<Message, String> colorsMap = new HashMap<Message, String>();
private void colorUsername(ViewHolder holder, Message message, String userName) {
String randomColor;
if(colorsMap.contains(message)) {
randomColor = colorsMap.get(message);
}
else {
if (userName.equals(USERNAME_ME)){
randomColor = "#000000";
}else if (message.getUserId()!=prevMsgUserID) {
do {
String[] array = context.getResources().getStringArray(R.array.username_colors);
randomColor = array[new Random().nextInt(array.length)];
}while (prevColor.equals(randomColor));
}
colorsMap.put(message, randomColor);
}
holder.nameTextView.setTextColor(Color.parseColor(randomColor));
}