Develop Reference

Optimizing ListView adapter to display dynamic content in individual ListView items

I'm trying to display a ListView where individual list items feature a dynamic number of elements. Each item list will have a TextView for a date. Following the date, there can be between 2-5 elements featured.
ListItemA
DateTextView
2-5 TextView
ListItemB
DateTextView
2-5 TextView
ListItemC
DateTextView
2-5 TextView
...
With this current method, it displays the blank TextViews at the bottom of the ListView's item. Would there be a better way to do this?
I thought that convertView would have had methods to add layout elements to it, but that's not the case.
Adapter's getView method:
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if(convertView == null){
holder = new ViewHolder();
convertView = this.inflater.inflate(R.layout.layout_list_item, parent, false);
holder.text_date_cashout = (TextView) convertView.findViewById(R.id.text_date_cashout);
holder.dynamic_views.add((TextView) convertView.findViewById(R.id.text_cashout1));
holder.dynamic_views.add((TextView) convertView.findViewById(R.id.text_cashout2));
holder.dynamic_views.add((TextView) convertView.findViewById(R.id.text_cashout3));
holder.dynamic_views.add((TextView) convertView.findViewById(R.id.text_cashout4));
holder.dynamic_views.add((TextView) convertView.findViewById(R.id.text_cashout5));
convertView.setTag(holder);
}
else{
holder = (ViewHolder) convertView.getTag();
}
//get and set date from current cashOutHistory
CashOutHistory coh = cashOutHistory.get(position);
holder.text_date_cashout.setText(coh.getDate());
//loop individual cashOuts to display their values
int i = 0;
for (CashOut co : coh.getCashOutHistory() ){
holder.dynamic_views.get(i).setText(co.toString());
i++;
}
return convertView;
}
private class ViewHolder{
TextView text_date_cashout;
ArrayList<TextView> dynamic_views = new ArrayList<TextView>(5);
}
List item layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=""
android:id="#+id/text_date_cashout" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=""
android:id="#+id/text_cashout1" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=""
android:id="#+id/text_cashout2" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=""
android:id="#+id/text_cashout3" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=""
android:id="#+id/text_cashout4" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=""
android:id="#+id/text_cashout5" />
</LinearLayout>
Edit #1
Loop showing and hidding the TextViews in my list item:
//loop individual cashOuts to display their values
int i = 0;
for (CashOut co : coh.getCashOutHistory() ){
holder.dynamic_views.get(i).setText(co.toString());
i++;
}
while(i < 5){
holder.dynamic_views.get(i).setVisibility(View.GONE);
i++;
}

You can hide each view you don't need showing for that particular item by using:
Boolean someCondition = true;
if (someCondition)
holder.dynamic_views.get(i).setVisibility(View.GONE);
Hope this helps.

I cannot load listview on my Android phone

I cannot load listview on my phone. It displays the error in the logcat:
03-24 05:27:14.537: D/AbsListView(22125): unregisterIRListener() is called
My code is as follow
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
setHasOptionsMenu(true);
rootView = inflater.inflate(R.layout.fragment_event, container, false);
listView = (ListView) rootView.findViewById(R.id.eventListView);
listView.setVisibility(View.VISIBLE);
listView.setClickable(true);
EventArrayAdapter eArrayAdapter = new EventArrayAdapter(getActivity(), R.layout.rowlayout, events);
listView.setAdapter(eArrayAdapter);
eArrayAdapter.notifyDataSetChanged();
return rootView;
}
rowlayout.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:id="#+id/eventDay"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#1d766f"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#FFFFFF" />
<TextView
android:id="#+id/eventMonth"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#e2fffd"
android:textAppearance="?android:attr/textAppearanceSmall"
android:textColor="#0083af" />
<TextView
android:id="#+id/eventTime"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#e2fffd"
android:textAppearance="?android:attr/textAppearanceSmall"
android:textColor="#1d766f" />
</LinearLayout>
<LinearLayout android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="#+id/eventName"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textColor="#0083af"/>
<TextView
android:id="#+id/eventLocation"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
</LinearLayout>
mainlayout.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<Button
android:id="#+id/btnAllEvent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="All Events"
/>
<ListView
android:id="#+id/eventListView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:drawSelectorOnTop="false"/>
</LinearLayout>
Unfortunately, it doesnot show anything, even the listview itself. Please help me. Thank you
Update: I use the view Holder pattern

You have to return the view simply.
Also For a better scrolling you need to implement and understand the ViewHolder pattern.
Reason why you should use it is because:
layout inflations are expensive operations.
If you do something like this:
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater mInflater = mContext.getLayoutInflater();
View item = mInflater.inflate(R.layout.list_item, null);
MyObj data = getItem(position);
((TextView) item.findViewById(R.id.text1)).setText(data.text1);
((TextView) item.findViewById(R.id.text2)).setText(data.text2);
((TextView) item.findViewById(R.id.longtext)).setText(data.longText);
return item;
}
Please don't do it, because the adapter will create a new view for every position and if you have a very long list it will cause lag scroll. Imagine you have 500 item in the list, the adapter have to create 500 views!!!
So the ViewHolder pattern fix this problem by changing that code from above like this:
public View getView(int position, View convertView, ViewGroup parent) {
Log.d(TAG, "position=" + position);
ViewHolder holder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.list_item, parent, false);
holder = new ViewHolder();
holder.text1 = (TextView) convertView.findViewById(R.id.text1);
holder.text2 = (TextView) convertView.findViewById(R.id.text2);
holder.longtext = (TextView) convertView.findViewById(R.id.longtext);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
MyObj data = getItem(position);
holder.text1.setText(data.text1);
holder.text2.setText(data.text2);
holder.longtext.setText(data.longText);
return convertView;
}
The convertView from the getView method will have a non-null value when ListView is asking you recycle the row layout. So, when convertView is not null, you should simply update its contents instead of inflating a new row layout.
What this snippet does goes like this:
If the ConvertView is null it will inflate the layout and save each view under the ViewHolder class, what ViewHolder does is to save the views, then you save the ViewHolder in the ConverView with setTag(Object object), If convertView isn't Null then it get the ViewHolder object like this: holder = (ViewHolder) convertView.getTag();
And then it get the current object from the list with the position variable from the getView method and reference everyView through the ViewHolder instance.
Also don't use android:layout_height="wrap_content" because the listView has to call getView() lot of time to know how big it should be, so use android:layout_height="fill_parent" instead.

how to add multiple imageview on listview row with horizontal scroll view

I want to display multiple imageview and text view on every row of listview and number of row is not fix (number of rows integer can be fetched from server)
How can i add horizontal scroll view in every row.
i am going to use for loop for number of imageview in getView method is it right way to do that.
My question is how can i inflate horizontal scroll with numbers image views in row in getview method
public View getView(final int position, View convertView,
ViewGroup parent)
{
final ViewHolder viewHolder;
viewHolder = new ViewHolder();
// View vi = convertView;
//if (vi == null)
//{
int Numberofimageview=2;
for(int i=0;i<Numberofimageview;i++)
{
// assume i want to display 2 imageview in every row
LayoutInflater inflater = (LayoutInflater) con
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.my_row_layout, parent,
false);
viewHolder.title = (TextView) convertView.findViewById(R.id.title);
Log.d("myapp", "position" + position);
convertView.setTag(viewHolder);
// }
// else
// {
// viewHolder=(ViewHolder)convertView.getTag();
// }
viewHolder.title.setText(data.get(position));
}
return convertView;
}
This is xml for row
RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<ImageView
android:id="#+id/wagon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:src="#drawable/wagon" />
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/wagon"
android:layout_centerVertical="true"
android:layout_marginLeft="16dp"
android:src="#drawable/video" />
<TextView
android:id="#+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/imageView1"
android:layout_marginLeft="33dp"
android:layout_toRightOf="#+id/imageView1"
android:text="title of file" />
<TextView
android:id="#+id/type"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/title"
android:layout_alignRight="#+id/title"
android:layout_marginBottom="18dp"
android:text="type of file" />

Try to include your relativeLayout into a HorizontalScrollView
<HorizontalScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<RelativeLayout>[...]</RelativeLayout>
</HorizontalScrollView>

Create a custom listview. Create a xml file. within the main linear layout of the xml file put imageview and textview. Make sure the orientation of the linear layout is horizontal.. Make use of that xml file in getview methood

Textview background repeats in a listview

So the problem that i am facing, is that when i try to set dynamically the background of a textView that belongs to a listView, the background that i set, is set for other textViews too..it repeats itself...i saw that these problems with listView items are common, but couldn't find a solution for me
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.product_item, null);
holder = new ViewHolder();
holder.increment = (Button) convertView.findViewById(R.id.increment);
holder.decrement = (Button) convertView.findViewById(R.id.decrement);
holder.pic_view_quantity = (TextView) convertView.findViewById(R.id.pic_view_quantity);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.pic_view_quantity.setText(products.get(position).getQuantity());
if (products.get(position).getQuantity().matches("[0-9]+")){
holder.pic_view_quantity.setBackgroundResource(R.drawable.transparent_rectangle); //this is where i set the background, to items that have a quantity
}
return convertView;
}
My layout:
<RelativeLayout
android:id="#+id/relativelayout"
android:layout_width="70dp"
android:layout_height="70dp" >
<ImageView android:id="#+id/pic_view"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginTop="5sp"
android:contentDescription="#string/product_picture" >
</ImageView>
<TextView
android:id="#+id/pic_view_quantity"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/pic_view"
android:layout_alignTop="#+id/pic_view"
android:layout_alignRight="#+id/pic_view"
android:layout_alignBottom="#+id/pic_view"
android:layout_margin="1dp"
android:textSize="36sp"
android:gravity="center"
android:textColor="#FF0000" />
</RelativeLayout>

Add an else to the following statement
if (products.get(position).getQuantity().matches("[0-9]+")){
holder.pic_view_quantity.setBackgroundResource(R.drawable.transparent_rectangle); //this is where i set the background, to items that have a quantity
}
else {
holder.pic_view_quantity.setBackgroundResource(0);
}

Android, changing background of list in array adapter?

In my application i have list which i inflate it with array adapter. every thing is OK and i have my result in the list.
I like to change background color of list (even rows red for example and odd rows green).
This is xml of my rows:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<RelativeLayout
android:id="#+id/rllist"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="15dip"
android:layout_marginBottom="15dip"
>
<TextView
android:id="#+id/outstanding_contractdate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#ffffff"
android:textSize="15sp" />
<TextView
android:id="#+id/outstanding_contractno"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="#id/outstanding_contractdate"
android:paddingLeft="20dip"
android:textColor="#ffffff"
android:textSize="15sp" />
<TextView
android:id="#+id/outstanding_contractamount"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:textSize="15sp" />
</RelativeLayout>
</LinearLayout>
I have written following codes:
static class ViewHolder {
RelativeLayout rlList;
TextView tvContDate;
TextView tvContNo;
TextView tvContAmount;
}
and in Array Adapter I have this one:
public View getView(int position, View convertView, ViewGroup parent){
ViewHolder holder;
View row = convertView;
if(row == null){
LayoutInflater inflater = getLayoutInflater();
row = inflater.inflate(R.layout.list_outstanding, parent, false);
//convertView = mInflater.inflate(R.layout.list_outstanding, parent, false);
holder = new ViewHolder();
holder.rlList = (RelativeLayout) convertView.findViewById(R.id.rllist);
holder.tvContDate = (TextView) row.findViewById(R.id.outstanding_contractdate);
holder.tvContNo = (TextView) row.findViewById(R.id.outstanding_contractno);
holder.tvContAmount = (TextView) row.findViewById(R.id.outstanding_contractamount);
row.setTag(holder);
} else {
holder = (ViewHolder) row.getTag();
}
holder.tvContDate.setText(llData.get(position).split(",")[0].trim());
holder.tvContNo.setText(llData.get(position).split(",")[1].trim());
holder.tvContAmount.setText(llData.get(position).split(",")[2].trim());
if(position%2 != 0)
holder.rlList.setBackgroundColor(0x00FF00);
else
holder.rlList.setBackgroundColor(0XFF0000);
return(row);
}
after running application when i reach to this code, an error occurs. according to LogCat it is "Null Pointer Exception" and points to this line in getView():
holder.rlList = (RelativeLayout) convertView.findViewById(R.id.rllist);
it seems everything is OK, but I don't know where my problem is?!!!
===========
Update
I have changed above line to:
holder.rlList = (RelativeLayout) row.findViewById(R.id.rllist);
and now i have my result but background did not applied?!!!

Try using
if(position%2 != 0)
holder.rlList.setBackgroundColor(Color.parseColor("#00ff00"));
else
holder.rlList.setBackgroundColor(Color.parseColor("#ff0000"));