For creating custom list view as a library in android

Question

we want to create a list view using adapter and we want to set the properties of the the list item outside the adapter.

For instance ,the list view contains 200 rows and 14 column, then we need to create the list item using adapter.Here the objects in adapter is creating based on the which items shown in screen.

After creating adapter ,after outside adapter we want to put getter,setter for the item 198 means .If initially in device the items upto 10 is diplayed means then then 10 items objects is created in adapter but the remaining is created when user scroll down

So null pointer execption is arised for the item 198.

I want to create a ListView as a custom component.In that the user can add any number of rows,any number of columns,etc
Any items as a list view,etc.

My aim is to create library for list view .In that list view user can add any number of rows,any number of columns,any items textview,spinner,etc.I need suggestions how to achieve it

All are welcome to give their ideas.

Answer 1

What you need is to implement LazyListView.

And I think you have a nice tutorial here to start with.

Answer 2

try use: your xml list file item.xml:

<LinearLayout>
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<CheckBox
android:id="@+id/cbBox"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</CheckBox>
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginLeft="5dp"
android:layout_weight="1"
android:orientation="vertical">
<TextView
android:id="@+id/tvDescr"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:text=""
android:textSize="20sp">
</TextView>
<TextView
android:id="@+id/tvPrice"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:layout_marginRight="10dp"
android:text="">
</TextView>
</LinearLayout>
<ImageView
android:id="@+id/ivImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_launcher">
</ImageView>
<LinearLayout/>

And your class adapter

public class BoxAdapter extends BaseAdapter {
Context ctx;
LayoutInflater lInflater;
ArrayList<Product> objects;

BoxAdapter(Context context, ArrayList<Product> products) {
ctx = context;
objects = products;
lInflater = (LayoutInflater) ctx
    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

@Override
public int getCount() {
return objects.size();
}

@Override
public Object getItem(int position) {
return objects.get(position);
}

@Override
public long getItemId(int position) {
return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if (view == null) {
view = lInflater.inflate(R.layout.item, parent, false);
}

Product p = getProduct(position);
((TextView) view.findViewById(R.id.tvDescr)).setText(p.name);
((TextView) view.findViewById(R.id.tvPrice)).setText(p.price + "");
((ImageView) view.findViewById(R.id.ivImage)).setImageResource(p.image);

CheckBox cbBuy = (CheckBox) view.findViewById(R.id.cbBox);
cbBuy.setOnCheckedChangeListener(myCheckChangList);
cbBuy.setTag(position);
cbBuy.setChecked(p.box);
return view;
}

Product getProduct(int position) {
return ((Product) getItem(position));
}

ArrayList<Product> getBox() {
ArrayList<Product> box = new ArrayList<Product>();
for (Product p : objects) {
if (p.box)
box.add(p);
}
return box;
}

OnCheckedChangeListener myCheckChangList = new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView,
    boolean isChecked) {
 getProduct((Integer) buttonView.getTag()).box = isChecked;
}
}; 
}

And your class for product

public class Product {
String name;
int price;
int image;
boolean box;

Product(String _describe, int _price, int _image, boolean _box) {
name = _describe;
price = _price;
image = _image;
box = _box;
}
}

And your main activity use the create adapter

boxAdapter = new BoxAdapter(this, products);
ArrayList<Product> products = new ArrayList<Product>();
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState) 
...
//create adapter
fillData()
boxAdapter = new BoxAdapter(this, products);

// use lists
ListView lvMain = (ListView) findViewById(R.id.lvMain);
lvMain.setAdapter(boxAdapter);
}

// data for adapter
void fillData() {
for (int i = 1; i <= 20; i++) {
products.add(new Product("Product " + i, i * 1000, R.drawable.ic_launcher, false));
}