Exp 4: Study of User Interface Design-Views and View Groups

Code for activity_main.xml

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

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

    xmlns:tools="http://schemas.android.com/tools"

    android:id="@+id/activity_main"

    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="com.example.administrator.exp4_views_buttonevent.MainActivity">



    <TextView

        android:id="@+id/TextView1"

        android:layout_width="match_parent"

        android:layout_height="30dp"

        android:text="Hello Everyone...!!"

        android:fontFamily="cursive"

        android:textSize="24sp"

        android:textColor="@android:color/holo_purple" />



    <ImageView

        android:id="@+id/ImgVw1"

        android:layout_width="match_parent"

        android:layout_height="250dp"

        android:src="@drawable/img2"



        android:layout_below="@id/TextView1"/>



    <TextView

        android:id="@+id/TextView2"

        android:layout_width="match_parent"

        android:layout_height="100dp"

        android:text=" Hello, This is Old Text"

        android:layout_below="@+id/ImgVw1"

        android:layout_alignParentLeft="true"

        android:layout_alignParentStart="true"

        android:layout_marginTop="25dp"

        android:textColor="@android:color/holo_blue_dark"

        android:textSize="24sp"

        android:fontFamily="cursive"

        android:textAlignment="center" />

    <Button

        android:id="@+id/Btn_ChaneText"

        android:text="Change Text"

        android:onClick="changeText"

        android:layout_width="match_parent"

        android:layout_height="100dp"

        android:layout_below="@+id/TextView2"

        android:textSize="24sp"

        android:fontFamily="cursive"

        android:textColor="@android:color/black"

        android:textStyle="normal|italic" />







</RelativeLayout>

Code for MainActivity.java

package com.example.administrator.exp4_views_buttonevent;



import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.TextView;



public class MainActivity extends AppCompatActivity {

int flag=0;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

    }



    public void changeText(View view) {



        if(flag==0) {

            TextView obj = (TextView) findViewById(R.id.TextView2);

            obj.setText("Hello, This is New Text");

            flag = 1;

        }

        else

        {

            TextView obj = (TextView) findViewById(R.id.TextView2);

            obj.setText("Hello, This is Old Text ");

            flag = 0;



        }



    }

}

Output: