Android Adapter

Adapters are the link between a set of data and the AdapterView that displays the data.

AdapterView:

AdapterViews are ViewGroups that display child views given to it by an adapter.
An example of an AdapterView is a ListView.
Adapters also provide the child views that display the data in the AdapterView.
Adapters are responsible for supplying the data and creating the views representing each item.

Adapters get the data and pass it, along with a child view, to the parent AdapterView which displays the child view and the data

The Android Framework has a set of native adapters that are easy to use. You can also create your own custom adapters if you wish.

Two of Android’s common adapters are:

ArrayAdapter:

An ArrayAdapter is an adapter backed by an array of objects. It links the array to the Adapter View.

The default ArrayAdapter converts an array item into a String object putting it into a TextView. The text view is then displayed in the AdapterView (a ListView for example).

When you create the adapter, you need to supply the layout for displaying each array string. You can define your own or use one of Android’s, such as:

android.R.layout.simple_list_item_1

There are alternative constructors that you can use for more complex layouts.
You can also display images instead of strings.

Here's a tutorial where we use a custom ArrayAdapter to display a list of images and text, Using Bitmaps efficiently.

Example coding:

activity_main.xml

<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="match_parent"

 android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

 android:paddingTop="@dimen/activity_vertical_margin"

 tools:context=".MainActivity" >

    <ListView

 android:id="@+id/list"

android:layout_width="wrap_content"

android:layout_height="wrap_content" >

    </ListView>

</RelativeLayout>

list_singal.xml

<?xml version="1.0" encoding="utf-8"?>

 <TableLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

 android:layout_height="match_parent" >
    <TableRow>
        <ImageView

 android:id="@+id/img"

 android:layout_width="100dp"

 android:layout_height="100dp"/>

        <TextView

 android:id="@+id/txt"

 android:layout_width="wrap_content"

 android:textSize="40dp"

 android:layout_height="50dp" />

    </TableRow>
</TableLayout>

MainActivity:

public class MainActivity extends Activity {
    ListView list;
    String[] web = {
            "" +
                    "bird",
            "boy",
            "butterfly",
            "follower",
            "fruits",
            "karthi",
            "nature",
            "rose"    } ;
    Integer[] imageId = {
            R.drawable.bird,
            R.drawable.boy,
            R.drawable.butterfly,
            R.drawable.follower,
            R.drawable.fruits,
            R.drawable.monkey,
            R.drawable.nature,
            R.drawable.rose,


    };

    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        CustomList1 adapter = new                CustomList1(MainActivity.this, web, imageId);
        list=(ListView)findViewById(R.id.list);
        list.setAdapter(adapter);
        list.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            @Override            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id) {
                Toast.makeText(MainActivity.this, "You Clicked at " +web[+ position], Toast.LENGTH_SHORT).show();

            }
        });

    }

}

CustomList1

public class CustomList1 extends ArrayAdapter<String> {
    private final Activity context;
    private final String[] web;
    private final Integer[] imageId;
    public CustomList1(Activity context,
                      String[] web, Integer[] imageId) {
        super(context, R.layout.list_single, web);
        this.context = context;
        this.web = web;
        this.imageId = imageId;

    }
    @Override    public View getView(int position, View view, ViewGroup parent) {
        LayoutInflater inflater = context.getLayoutInflater();
        View rowView= inflater.inflate(R.layout.list_single, null, true);
        TextView txtTitle = (TextView) rowView.findViewById(R.id.txt);

        ImageView imageView = (ImageView) rowView.findViewById(R.id.img);
        txtTitle.setText(web[position]);

        imageView.setImageResource(imageId[position]);
        return rowView;
    }
}

Output:

SimpleCursorAdapter:

The SimpleCursorAdapter links the data contained in a Cursor to an Adapter View.

Cursors:

A cursor is a set of data. You usually get a cursor when you do a database query. The result of your query is contained in the cursor.

The SimpleCursorAdapter binds the Cursor data to an Adapter View. You define a layout that controls how each row of data is displayed.

Each row’s view is populated using the column values of the corresponding row in the cursor.

This layout is then displayed in the Adapter View, like a ListView for example.

The SimpleCursorAdapter gets the data out of the Cursor, puts each row of data in a layout that you define and then displays it in the Adapter View.

When you construct the SimpleCursorAdapter, you specify which column’s data is to be retrieved from the cursor.

You also specify which fields in your layout are to display this data.

The adapter then creates a new view for each cursor entry and populates it with the corresponding cursor column values.

Other useful Adapters:

CursorAdapter

A CursorAdapter links a Cursor’s data to a List View.

You must include the database’s _id column as it’s used in processing the list item’s selection.

The SimpleCursorAdapter is a subclass of CursorAdapter.

The SimpleCursorAdapter is easier to use while the CursorAdapter requires more work but allows more customization.

SimpleAdapter

The SimpleAdapter links static data to views defined in a layout file.

You specify the data as an ArrayList of Maps.

Each entry in the ArrayList will display as a row in a list.

BaseAdapter

The BaseAdapter is a common base class for an Adapter that can be used in a ListView and a Spinner.

ListAdapter

The ListAdapter links the data and a ListView displaying the data.

The List View can display any data type provided it’s wrapped in a ListAdapter.

next we see about Listview.

List View

Listview is a view group that displays a list of scrollable items.

The list items are automatically inserted to the list using an `Adapter` that pulls content from a source such as an array or database query and converts each item result into a view that's placed into the list.

Example Coding:

Activity_main.xml

<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="match_parent"

 android:paddingBottom="@dimen/activity_vertical_margin"

 android:paddingLeft="@dimen/activity_horizontal_margin"

 android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context=".MainActivity" >

    <ListView

android:id="@+id/list"

android:layout_width="wrap_content"

 android:layout_height="wrap_content" >

    </ListView>

</RelativeLayout>

list.xml

<?xml version="1.0" encoding="utf-8"?>

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

 android:layout_width="match_parent"    android:layout_height="match_parent" >


    <TextView

 android:layout_width="wrap_content"

 android:layout_height="wrap_content"

android:text="New Text"

 android:id="@+id/name"

 android:layout_alignParentTop="true"

 android:layout_alignParentStart="true" />

    <TextView

 android:layout_width="wrap_content"

android:layout_height="wrap_content"

 android:text="New Text"

 android:id="@+id/emailid"

 android:layout_below="@+id/name"

 android:layout_alignParentStart="true" />
</RelativeLayout>

MainActivity:

public class MainActivity extends ActionBarActivity {
    ListView list;
    String[] name = {
            "" +
                    "Lucy",
            "Harry",
            "Lizzy",
            "Monty",

    } ;
    String[] emailid = {
            ""+"lucy@there.com","harry@sally.com","lizzy@dizzy.com","monty.python.com",


    };

    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Adapter adapter = new                Adapter(MainActivity.this, name, emailid);
        list=(ListView)findViewById(R.id.list);
        list.setAdapter(adapter);
    }

    @Override    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.

 getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will

        // automatically handle clicks on the Home/Up button, so long

       // as you specify a parent activity in AndroidManifest.xml.

        int id = item.getItemId();

        //noinspection SimplifiableIfStatement

        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

Adapter:

public class Adapter extends ArrayAdapter<String> {
    private final Activity context;
    private final String[] name;
    private final String[] emailid;
    public Adapter(Activity context,
                   String[] web, String[] imageId) {
        super(context, R.layout.list,web);
        this.context = context;
        this.name = web;
        this.emailid = imageId;
    }

    @Override    public View getView(int position, View convertView, ViewGroup parent) {

        LayoutInflater inflater = context.getLayoutInflater();
        View rowView= inflater.inflate(R.layout.list, null, true);
        TextView txtTitle = (TextView) rowView.findViewById(R.id.txt);

        TextView imageView = (TextView) rowView.findViewById(R.id.img);
        txtTitle.setText(name[position]);
        imageView.setText(emailid[position]);
        return rowView;
    }
}

Falgee Software Development Training Institute

Sunday 1 November 2015

Android Adapter

Android Adapter

Adapters are the link between a set of data and the AdapterView that displays the data.

AdapterView:

Adapters get the data and pass it, along with a child view, to the parent AdapterView which displays the child view and the data

The Android Framework has a set of native adapters that are easy to use. You can also create your own custom adapters if you wish.

Two of Android’s common adapters are:

ArrayAdapter:

An ArrayAdapter is an adapter backed by an array of objects. It links the array to the Adapter View.

The default ArrayAdapter converts an array item into a String object putting it into a TextView. The text view is then displayed in the AdapterView (a ListView for example).

MainActivity:

Output:

Cursors:

Other useful Adapters:

CursorAdapter

SimpleAdapter

BaseAdapter

ListAdapter

List View

Listview is a view group that displays a list of scrollable items.

The list items are automatically inserted to the list using an `Adapter` that pulls content from a source such as an array or database query and converts each item result into a view that's placed into the list.

Example Coding:

Activity_main.xml

MainActivity:

Adapter:

Output:

Blog Archive

Popular Posts

Falgee Software Development Training Institute

Sunday 1 November 2015

Android Adapter

Android Adapter

Adapters are the link between a set of data and the AdapterView that displays the data.

AdapterView:

Adapters get the data and pass it, along with a child view, to the parent AdapterView which displays the child view and the data

The Android Framework has a set of native adapters that are easy to use. You can also create your own custom adapters if you wish.

Two of Android’s common adapters are:

ArrayAdapter:

An ArrayAdapter is an adapter backed by an array of objects. It links the array to the Adapter View.

The default ArrayAdapter converts an array item into a String object putting it into a TextView. The text view is then displayed in the AdapterView (a ListView for example).

MainActivity:

Output:

Cursors:

Other useful Adapters:

CursorAdapter

SimpleAdapter

BaseAdapter

ListAdapter

List View

Listview is a view group that displays a list of scrollable items.

The list items are automatically inserted to the list using an Adapter that pulls content from a source such as an array or database query and converts each item result into a view that's placed into the list.

Example Coding:

Activity_main.xml

MainActivity:

Adapter:

Output:

Social Profiles

Blog Archive

Popular Posts

The list items are automatically inserted to the list using an `Adapter` that pulls content from a source such as an array or database query and converts each item result into a view that's placed into the list.