Creating Services in Android

Creating Services in Android

Grid View

GridView is a ViewGroup that displays items in a two-dimensional, scrollable grid. The grid items are automatically inserted to the layout using a ListAdapter.
Here we create a grid of text values. When an item is selected, a toast message will display the position of the text value and image of  the text value.

1. Start a new project named MyGridView.
2. Find some photos you'd like to use, or download these sample images. Save the image files into the project's res/drawable/ directory.
3. Open the res/layout/main.xml file and insert the following:
   <?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" >
   
       <TextView
           android:layout_width="fill_parent"
           android:layout_height="wrap_content"
           android:text="@string/hello" />
   
       <TextView
           android:id="@+id/textView1"
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:text="select one value"
           android:textColor="#FF00FF"
           android:textAppearance="?android:attr/textAppearanceLarge" />
   
       <GridView
           android:id="@+id/gridView1"
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:numColumns="3" >
       </GridView>
   
   </LinearLayout>

 4.Open the class MyGeridView.java and inser the following codes.


package com.anna;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.GridView;
import android.widget.Toast;

public class MyGridViewActivity extends Activity {
    String s[]={"Apple","Baby","Car","cat","Flower"};
    GridView gv;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
       
        gv=(GridView)findViewById(R.id.gridView1);
        ArrayAdapter<String> arr=new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,s);
        gv.setAdapter(arr);
        gv.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
                String s1=gv.getItemAtPosition(position).toString();
                int p=position;
                Toast.makeText(MyGridViewActivity.this, ""+position, Toast.LENGTH_SHORT).show();
                switch (p) {
                case 0:
                   
                Intent iapple =new Intent(MyGridViewActivity.this,Apple.class);
                startActivity(iapple);
                   
                break;
               
                case 1:
                    Intent ibaby =new Intent(MyGridViewActivity.this,Baby.class);
                    startActivity(ibaby);
                    break;
                case 2:
                   
                    Intent icar =new Intent(MyGridViewActivity.this,Car.class);
                    startActivity(icar);
                       
                    break;
                   
                case 3:
                        Intent icat =new Intent(MyGridViewActivity.this,Cat.class);
                        startActivity(icat);
                        break;
                case 4:
                       
                        Intent ifl =new Intent(MyGridViewActivity.this,Flower.class);
                        startActivity(ifl);
                           
                        break;
                       

                default:
                    Toast.makeText(MyGridViewActivity.this, ""+position, Toast.LENGTH_SHORT).show();
                   
                    break;
                } 
               
                }
               
               
           
        });

       
    }
}


After the main.xml layout is set for the content view, the GridView is captured from the layout with findViewById(int). The setAdapter() method then sets a custom adapter (ImageAdapter) as the source for all items to be displayed in the grid. The ImageAdapter is created in the next step.
To do something when an item in the grid is clicked, the setOnItemClickListener() method is passed a new AdapterView.OnItemClickListener. This anonymous instance defines the onItemClick() callback method to show a Toast that displays the index position (zero-based) of the selected item.
To display the image of the item selected by using the switch-case and Intent.

5.Create new classes to display the item selected.Here giving an example classes-Apple.java.
Here we using position id to find out which item is selected.According to the position selected,the them display will change.

Apple.java

package com.anna;

import android.app.Activity;
import android.os.Bundle;

public class Apple extends Activity{
   

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.apple);
    }

}


Like this class we can create another classes too.


6.To set the images in to the layout by following codes:
eg: apple.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" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/apple" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="APPLE"
        android:textAppearance="?android:attr/textAppearanceLarge" />

</LinearLayout>

 7.Run the program









then click one item.

Spinner in Android

Spinner is a widget similar to the drop-down list for selecting items.

Example program to display the fruits list using spinner.

1.Create one class "arraywspin"
2.Open the res/layout/main.xml file and insert the following:

<?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" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Select one item"
        android:textColor="#FF00FF"
        android:textAppearance="?android:attr/textAppearanceLarge" />

        <Spinner
        android:id="@+id/spinner1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:prompt="@string/fruits"/>
  
</LinearLayout>

Notice that the TextView's android:text attribute and the Spinner's android:prompt attribute both reference the same string resource. This text behaves as a title for the widget. When applied to the Spinner, the title text will appear in the selection dialog that appears upon selecting the widget.

3.Create array.xml in res/values and edit the file like following codes to display the items.


<?xml version="1.0" encoding="utf-8"?>
<resources>
  
    <string-array name="fruit_array">
        <item>Apple</item>
        <item>Blackberry</item>
        <item>Cherry</item>
        <item>Guava</item>
        <item>Mango</item>
      
    </string-array><string name="fruits">Choose a fruit</string>
</resources>



4..then open the arraywspin.java ,and insert the following coding to display the spinner.

package com.ipsr;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;
import android.widget.AdapterView.OnItemSelectedListener;

public class ArraywspinActivity extends Activity {
    Spinner sp;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
      
        sp=(Spinner)findViewById(R.id.spinner1);
        ArrayAdapter<CharSequence> arr=ArrayAdapter.createFromResource(this,R.array.fruit_array,android.R.layout.simple_dropdown_item_1line);
        sp.setAdapter(arr);
      sp.setOnItemSelectedListener(new OnItemSelectedListener() {
            public void onItemSelected(AdapterView<?> arg0, View arg1,
                    int position, long id) {
                String item= sp.getItemAtPosition(position).toString();
                Toast.makeText(ArraywspinActivity.this,
                        "You have selected the item: " +item,
                        Toast.LENGTH_SHORT).show();
              
            }public void onNothingSelected(AdapterView<?> arg0) {
              
                }
              
            });
        }
    }


After the main.xml layout is set as the content view, the Spinner widget is captured from the layout with findViewById(int). The createFromResource() method then creates a new ArrayAdapter, which binds each item in the string array to the initial appearance for the Spinner (which is how each item will appear in the spinner when selected).  Then setDropDownViewResource(int) is called to define the appearance for each item when the widget is opened (simple_spinner_dropdown_item is another standard layout defined by the platform). Finally, the ArrayAdapter is set to associate all of its items with the Spinner by calling setAdapter(T).

The AdapterView.OnItemSelectedListener requires the onItemSelected() and onNothingSelected() callback methods. The former is called when an item from the AdapterView is selected, in which case, a short Toast message displays the selected text; and the latter is called when a selection disappears from the AdapterView, which doesn't happen in this case, so it's ignored.


5.Then run the program.