Develop an application that uses Layout Managers and event listeners.

1)Open eclipse or android studio and select new android project
2)Give project name and select next
3) Choose the android version.Choose the lowest android version(Android 2.2) and select next
4) Enter the package name.package name must be two word seprated by comma and click finish
5)Go to package explorer in the left hand side.select our project.
6)Go to res folder and select layout.Double click the main.xml file.Add the code below

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/relativeLayout1"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >

<LinearLayout
            android:id="@+id/linearLayout1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentRight="true"
            android:layout_alignParentTop="true" >

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:text="ADDITION"
                android:textSize="20dp" >

            </TextView>
        </LinearLayout>
<LinearLayout
    android:id="@+id/linearLayout2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentRight="true"
    android:layout_below="@+id/linearLayout1" >
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="ENTER NO 1" >
    </TextView>
<EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight="0.20"
      android:id="@+id/edittext1"
    android:inputType="number">
    </EditText>
</LinearLayout>
<LinearLayout
    android:id="@+id/linearLayout3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentRight="true"
    android:layout_below="@+id/linearLayout2" >
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="ENTER NO 2" >
    </TextView>
<EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight="0.20"
      android:id="@+id/edittext2"
    android:inputType="number">
    </EditText>
</LinearLayout>
<LinearLayout
    android:id="@+id/linearLayout4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentRight="true"
    android:layout_below="@+id/linearLayout3" >
 
<Button
        android:layout_width="wrap_content"
        android:id="@+id/button1"
        android:layout_height="wrap_content"
        android:text="Addition"
        android:layout_weight="0.50" />
<Button
        android:layout_width="wrap_content"
        android:id="@+id/button3"
        android:layout_height="wrap_content"
        android:text="subtraction"
        android:layout_weight="0.50" />
<Button
        android:layout_width="wrap_content"
        android:id="@+id/button2"
        android:layout_height="wrap_content"
        android:text="CLEAR"
        android:layout_weight="0.50" />
</LinearLayout>
 <View
                android:layout_height="2px"
                android:layout_width="fill_parent"
                android:layout_below="@+id/linearLayout4"
                android:background="#DDFFDD"/>
    </RelativeLayout>

7) Now select mainactivity.java file and type the following code.

package layout.ne;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class LAYOUTActivity extends Activity {
    /** Called when the activity is first created. */
    EditText txtData1,txtData2;
    float num1,num2,result1,result2;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    
      
       Button add = (Button) findViewById(R.id.button1);
        add.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
            try
            {
                 txtData1 = (EditText) findViewById(R.id.edittext1);
                    txtData2 = (EditText) findViewById(R.id.edittext2);
                num1 = Float.parseFloat(txtData1.getText().toString());
                num2 = Float.parseFloat(txtData2.getText().toString());
            result1=num1+num2;
            Toast.makeText(getBaseContext(),"ANSWER:"+result1,Toast.LENGTH_SHORT).show();
            }
            catch(Exception e)
            {
                Toast.makeText(getBaseContext(), e.getMessage(),
                        Toast.LENGTH_SHORT).show();
            }
        }
        });
         Button sub = (Button) findViewById(R.id.button3);
         sub.setOnClickListener(new OnClickListener() {

         public void onClick(View v) {
             try
             {
                  txtData1 = (EditText) findViewById(R.id.edittext1);
                 txtData2 = (EditText) findViewById(R.id.edittext2);
             num1 = Float.parseFloat(txtData1.getText().toString());
             num2 = Float.parseFloat(txtData2.getText().toString());
              result2=num1-num2;
             Toast.makeText(getBaseContext(),"ANSWER:"+result2,Toast.LENGTH_SHORT).show();
             }
             catch(Exception e)
             {
                 Toast.makeText(getBaseContext(), e.getMessage(),
                         Toast.LENGTH_SHORT).show();
             }
         }
         });
      
         Button clear = (Button) findViewById(R.id.button2);
         clear.setOnClickListener(new OnClickListener() {

         public void onClick(View v) {
             try
             {
             txtData1.setText("");
             txtData2.setText("");
             }
             catch(Exception e)
             {
                 Toast.makeText(getBaseContext(), e.getMessage(),
                        Toast.LENGTH_SHORT).show();
             }
           
           
         }
         });
      
    }
}

8)Now go to main.xml and right click .select run as option and select run configuration
9) Android output is present in the android emulator as shown in below.