Hi, this is my first tutorial here. I hope you’ll enjoy it. Ok, let’s start.
Let’s say that we want to create a Listview more different. We do not want to have only a small text, we want a button , a checkbox etc. in every Listview item. Here is a small tutorial where you can learn how to create an Adapter, the ” thing ” that will help us to personalize the ListView.
Ok, here is a small project where we’ll have:
-two classes : Listview.class (the class where we have the Listview ) and the ListviewAdapter.class ( the class which cantains the adapter for the Listview, with its help will populate the Listview as we want )
-two XML files : one where is the Listview and one where is the “design ” for each item. I’ve named them listview.xml and listview_row.xml .
I’ve decided to create an Adapter for a Listview whose each item will contain two Textviews , one for Firstname other for Lastname.Here is the content that we’re interested in. I will explain it by adding comments in the Java code.
Listview.class :
public class Listview extends Activity {
//Here are variables which contains the unique "keys", one for every text in a single Listview row.
static final String KEY_FIRSTNAME = "firstname",KEY_LASTNAME="lastname";
//Here are two arrays which contains some "interesting" words. Sorry, I had no inspiration.
String[] firstname = {"Gates","Cheese","Apple","Computer","Noidea","Something","Bestintheworld"};
String[] lastname = {"Tom","Dan","Andrew","Tyler","Austin","Jane","Bill"};
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listview);
//We declare the Listview. I had so much inspiration that I called it - listview .Yes, amazing.
ListView listview = (ListView) findViewById(R.id.lvGenuine);
//This arraylist stores all the the information that will be in the ListView
ArrayList<HashMap<String, String>> myArrayList = new ArrayList<HashMap<String, String>>();
//I need this " lenth" for the "for " part.
int length = firstname.length;
//I guess you know what this is.
for(int i=0;i<length;i++){
// This hashmap stores the information that exists only in the item.
HashMap<String, String> blablabla = new HashMap<String, String>();
blablabla.put(KEY_FIRSTNAME, firstname[i]);
blablabla.put(KEY_LASTNAME, lastname[i]);
//we save the hashmap in the ArrayList . Big thing retains the small one.
myArrayList.add(blablabla);
}
//We declare the adapter using the other class
ListviewAdapter adapter = new ListviewAdapter(this,myArrayList);
//We set the adapter, here is the "place" where we populate the List.
listview.setAdapter(adapter);
}
}ListviewAdapter.class:
public class ListviewAdapter extends BaseAdapter {//To create an adapter we have to extend BaseAdapter instead of Activity, or whatever.
private Activity activity;
private ArrayList<HashMap<String, String>> data;
private static LayoutInflater inflater=null;
public ListviewAdapter(Activity a, ArrayList<HashMap<String, String>> d) {
activity = a;
data=d;
inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public int getCount() { //get the number of elements in the listview
return data.size();
}
public Object getItem(int position) { //this method returns on Object by position
return position;
}
public long getItemId(int position) { //get item id by position
return position;
}
public View getView(int position, View convertView, ViewGroup parent) { //getView method is the method which populates the listview with our personalized rows
View vi=convertView;
if(convertView==null)
vi = inflater.inflate(R.layout.listview_row, null); //every item in listview uses xml "listview_row"'s design
TextView firstname = (TextView)vi.findViewById(R.id.tvFirstname); //Here are two textviews in the listview_row xml file
TextView lastname = (TextView)vi.findViewById(R.id.tvLastname); // You can enter anything you want, buttons, radiobuttons, images, etc.
HashMap<String, String> hash = new HashMap<String, String>(); //We need a HashMap to store our data for any item
hash = data.get(position);
firstname.setText(hash.get(Listview.KEY_FIRSTNAME)); //We personalize our row's items.
lastname.setText(hash.get(Listview.KEY_LASTNAME));
return vi;
}
}listview.xml :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ListView
android:id="@+id/lvGenuine"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</ListView>
</LinearLayout>and finally listview_row.xml :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/tvFirstname"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Firstname"
android:layout_marginLeft="20dip"
android:textSize="25dip" />
<TextView
android:id="@+id/tvLastname"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Lastname"
android:layout_marginLeft="40dip"
android:textSize="15dip" />
</LinearLayout>Here is a screenshot where you can see how it looks like :
You can download the entire project from here .
I hope you enjoyed the tutorial. I wait any kind of reviews and critics which I promise I will read and will think about them. If you’d like to see any tutorial for Android Development on www.androidgeniune.com you can leave a comment with your wish and I’ll try to help you.
This is all for now. Thank you for reading. See you !
