Android button/Android button action

UI design in android is very faster using xml

Here i am using linearLayout.
From this example we will know how to create a button and then give this button action.Lets see

Xml file description:
     At first i declared here a textview wich will changed after button action performed.
Each elements need a ID, for example textview id is myTextViev. we also define each content layout size and position (AbsoluteLayout).
Then i declared a button (id=myButton,name=Submit) and set button width height


Now you need to create a file named 'my_button_interface.xml' then paste the code below

//my_button_interface.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
     >
 <TextView 
  android:id="@+id/myTextViev"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
 />
    <Button 
     android:id="@+id/myButton"
  android:layout_width="100px"
  android:layout_height="50px"
  android:text="Submit" 
 />
</LinearLayout>

Code description:

First you need to set layout using setContentView(R.layout.my_button_interface).Now you get all elements of this layout.
If we want to get declare text view code is tv = (TextView) findViewById(R.id.myTextViev),now you
can set text in this textview.
For button action you need to implements OnClickListener,then everything is easy....

//AndroidButton.java

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class AndroidButton extends Activity implements OnClickListener {
   /** Called when the activity is first created. */
 
 Button btn;
 TextView tv;
 
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.my_button_interface);
       
       btn = (Button) findViewById(R.id.myButton);
       tv = (TextView) findViewById(R.id.myTextViev);
       
       tv.setText("This is old text");
       btn.setOnClickListener(this);
   }

 @Override
 public void onClick(View v) {
  // TODO Auto-generated method stub
  if (v.getId() == R.id.myButton) {
   tv.setText("This is new text");
  }
 }
}

output:


Before click button



After click button