TextView in Android

activity_main.xml
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<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"

    tools:context=".MainActivity">



    <TextView

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:textAppearance="?android:attr/textAppearanceLarge"

        android:text="Large Text"

        android:id="@+id/textView"

        android:layout_alignParentTop="true"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="41dp" />



    <Button

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="Show"

        android:id="@+id/button"

        android:layout_below="@+id/textView"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="77dp" />

</RelativeLayout>

MainActivity.Java

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package com.android.anil.textview;



import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;



public class MainActivity extends AppCompatActivity {

    TextView t1;

    Button b1;



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        b1=(Button)findViewById(R.id.button);

        t1=(TextView)findViewById(R.id.textView);

        b1.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                String s1="Hi Android";

                t1.setText(s1);

            }

        });

    }



}

Output is :

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