MainActivity .xml




<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 
xmlns:android="http://schemas.android.com/apk/res/android"    
xmlns:app="http://schemas.android.com/apk/res-auto"    
xmlns:tools="http://schemas.android.com/tools"    
android:layout_width="match_parent"    
android:layout_height="match_parent"    
tools:context=".MainActivity ">


    <TextView        
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
       android:padding="15dp"
        android:textStyle="bold"
        android:text="Welcome To Android Studio"
        android:textSize="25dp"
        app:layout_constraintBottom_toBottomOf="parent" 
       app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

    </TextView>

</androidx.constraintlayout.widget.ConstraintLayout>




MainActivity.java


package com.tn.loginpacttr;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_donor_list);
    }
}




Go AndroidManifest.xml




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


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


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


    package="com.tn.loginpacttr"


    tools:ignore="GoogleAppIndexingWarning">

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.CAMERA" />

    <uses-feature android:name="android.hardware.camera" />
    <uses-feature android:name="android.hardware.camera.autofocus" />

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.INTERNET" />

    <application        android:allowBackup="true"


        android:icon="@mipmap/ic_launcher"


        android:label="@string/app_name" 


       android:roundIcon="@mipmap/ic_launcher_round"


        android:supportsRtl="true" 


       android:theme="@style/AppTheme">
            <activity android:name=".Register"


            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".MainActivity"


        android:theme="@style/AppTheme.NoActionBar">


    </activity>
    </application>

</manifest>