What is
Base Adapter?
Now I am
going to talk about very interesting topic i.e Adapter. Guys, many times we
have seen list in various apps. How exiting is that to implement a ListView to
create a list in that look which we want. Adapter plays very important role,
when you implement a list view.
We use
Adapter to bind data. Like suppose you have data of various students, and you
wants to show that data in a list. It’s very simple, what you need to do is
just wrap the data in a single object and bind this object with adapter. Well
we will discuss all the procedure in brief.
Here we will
see two ways to use adapter first one is by Array Adapter and the second by
Base Adapter.
Array
Adapter
Step 1:
Create a new
xml file and name it “main.xml”. In this
xml I took a list view so that I can show data on a list. You can set height
and width of ListView according to your requirement.
<script type="syntaxhighlighter" class="brush: csharp"><![CDATA[
<?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="vertical"
>
<ListView
android:id="@+id/ll"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
</ListView>
</LinearLayout>
]]></script>
Step 2: find your ListView in your Activity and make a Array of
student’s name.
lv = (ListView)
findViewById(R.id.ll);
String[] names = {
"Amitabh", "Akanksha", "Mohit",
"Geeta", "Parul",
"Ammu",
"Atul", "Amit", ”Gourav” };
Step 3: create a ArrayAdapter and set this adapter for
your list view. This is the all, which you have done to create a list by using ArrayAdapter.
ArrayAdapter<String> aadapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, names) {
};
lv.setAdapter(aadapter);
Step 4: if you want to perform any operation
on click on any row of your list, so its quit simple just set
setOnItemClickListener on your ListView.
lv.setOnItemClickListener(new
OnItemClickListener() {
public void
onItemClick(AdapterView<?> parent, View view,
int
position, long id) {
view.setBackgroundColor(Color.BLUE);
}
});
Step 5: Now you have completed all the
actions to implement “ArrayAdapter”. Your Activity is now ready to
use. At last just set this “AdapterEx1Activity” as Launcher Activity in your manifest file.
public class
AdapterEx1Activity extends Activity {
/** Called when the activity is
first created. */
static ListView lv;
int pos;
String spos;
private int requestCode = 0;
private int resultCode = 1;
protected int itemId;
static int i2 = 0;
@Override
public void onCreate(Bundle
savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
lv = (ListView)
findViewById(R.id.ll);
String[] names = {
"Amitabh", "Akanksha", "mohit",
"Geeta", "Parul",
"Ammu",
"pavan", "Amit" };
ArrayAdapter<String>
aadapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1,
names) {
};
lv.setAdapter(aadapter);
lv.setOnItemClickListener(new
OnItemClickListener() {
public void
onItemClick(AdapterView<?> parent, View view,
int
position, long id) {
view.setBackgroundColor(Color.BLUE);
}
});
}
}
Step 6 : you will get the following output on
execute your code.
Base
Adapter
Now what you
think, the previous look is quite common? If you want to make a look as you want, So be
ready to do experiment with Base Adapter. The great benefit of Base Adapter is
that, you can customize the look of your list and you can have more than one
views in single row.
Step 7:
Create a new
xml file and name it “main.xml”. In this
xml I took a list view so that I can show data on a list. You can set height
and width of ListView according to your requirement.
<?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="vertical"
>
<ListView
android:id="@+id/ll"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
</ListView>
</LinearLayout>
Step 8: create a java file and name it “BaseAdapterEx” and inside your onCreate() method write this.
setContentView(R.layout.main);
ListView lv = (ListView)
findViewById(R.id.ll);
Step 9:
Create a
inner class inside your
“BaseAdapterEx” and name it MyAdpter
. Now extends “BaseAdapter” in your
inner class “MyAdpter” implement all the
unimplemented methods of BaseAdapter. Create two array and make them global so
that you can use it inside your inner class also.
String[] names = { "Akanksha", "Geeta", "Parul", "Amrita", "mohit", "Amit" };
String[] status = { "Rathore", "Darvai", "Chaturvedi","Sharma", "Jain" , "Dube" };
Step 10:
Create
another xml file and name it “inflate”.Make this xml file like this :
<?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/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Large Text"
android:textAppearance="?android:attr/textAppearanceLarge"
/>
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_launcher" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Large Text"
android:textAppearance="?android:attr/textAppearanceLarge"
/>
</LinearLayout>
Step 11:
Now I am
going to use this inflate.xml file in “MyAdpter” class.
So make your
“MyAdpter” class like this :
class
akankshaAdapter extends BaseAdapter {
private TextView tv1;
private TextView tv2;
private ImageView img;
public int getCount() {
// TODO
Auto-generated method stub
return
names.length;
}
public Object
getItem(int position) {
// TODO
Auto-generated method stub
return null;
}
public long
getItemId(int position) {
// TODO
Auto-generated method stub
return 0;
}
public View
getView(final int position, View v, ViewGroup parent) {
// TODO
Auto-generated method stub
LayoutInflater
lf = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
v =
lf.inflate(R.layout.inflate, null);
if(position==2)
{
v.setBackgroundColor(Color.CYAN);
}
tv1 =
(TextView) v.findViewById(R.id.textView1);
tv2 =
(TextView) v.findViewById(R.id.textView2);
img =
(ImageView) v.findViewById(R.id.imageView1);
System.out.print(position);
tv1.setText(names[position]);
tv2.setText(status[position]);
tv1.setOnClickListener(new
OnClickListener() {
public
void onClick(View v) {
//
TODO Auto-generated method stub
String
s=tv1.getText().toString();
System.out.println(s);
Toast.makeText(getApplicationContext(),
tv1.getText().toString(), 100).show();
}
});
return v;
}
}
Step 12: Now your whole class structure will looks like
public class
BaseAdapterEx extends Activity {
String[] names = { "Akanksha", "Geeta", "Parul", "Amrita", "mohit", "Amit" };
String[] status = { "Rathore", "Darvai", "Chaturvedi","Sharma", "Jain" , "Dube" };
@Override
protected void onCreate(Bundle savedInstanceState)
{
// TODO Auto-generated
method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ListView lv = (ListView)
findViewById(R.id.ll);
akankshaAdapter akadp =
new akankshaAdapter();
lv.setAdapter(akadp);
}
class MyAdpter extends BaseAdapter {
private TextView tv1;
private TextView tv2;
private ImageView img;
public int getCount() {
// TODO
Auto-generated method stub
return
names.length;
}
public Object
getItem(int position) {
// TODO
Auto-generated method stub
return null;
}
public long
getItemId(int position) {
// TODO
Auto-generated method stub
return 0;
}
public View
getView(final int position, View v, ViewGroup parent) {
// TODO
Auto-generated method stub
LayoutInflater
lf = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
v =
lf.inflate(R.layout.inflate, null);
if(position==2)
{
v.setBackgroundColor(Color.CYAN);
}
tv1 =
(TextView) v.findViewById(R.id.textView1);
tv2 = (TextView)
v.findViewById(R.id.textView2);
img =
(ImageView) v.findViewById(R.id.imageView1);
System.out.print(position);
tv1.setText(names[position]);
tv2.setText(status[position]);
tv1.setOnClickListener(new
OnClickListener() {
public
void onClick(View v) {
//
TODO Auto-generated method stub
String
s=tv1.getText().toString();
System.out.println(s);
Toast.makeText(getApplicationContext(),
tv1.getText().toString(), 100).show();
}
});
return v;
}
}
}
Step 13: Declare this Activity as Launcher
Activity in your manifest file and Run your project.
find the source code here
Nice tutorial.
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