Lab Programs

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context=".MainActivity">

</LinearLayout>

PROGRAM 1

<?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">

</androidx.constraintlayout.widget.ConstraintLayout>

package com.code.calculatorapp;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

Button btn_0,btn_1,btn_2,btn_3,btn_4,btn_5,btn_6,btn_7,btn_8,btn_9;
    Button btnclear,btndot,btnequal,btnadd,btnsub,btnmul,btndiv;
    EditText tres;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

btn_0=(Button) findViewById(R.id.btn_0);
        btn_0.setOnClickListener(this);
        btn_1=(Button) findViewById(R.id.btn_1);
        btn_1.setOnClickListener(this);
        btn_2=(Button) findViewById(R.id.btn_2);
        btn_2.setOnClickListener(this);
        btn_3=(Button) findViewById(R.id.btn_3);
        btn_3.setOnClickListener(this);
        btn_4=(Button) findViewById(R.id.btn_4);
        btn_4.setOnClickListener(this);
        btn_5=(Button) findViewById(R.id.btn_5);
        btn_5.setOnClickListener(this);
        btn_6=(Button) findViewById(R.id.btn_6);
        btn_6.setOnClickListener(this);
        btn_7=(Button) findViewById(R.id.btn_7);
        btn_7.setOnClickListener(this);
        btn_8=(Button) findViewById(R.id.btn_8);
        btn_8.setOnClickListener(this);
        btn_9=(Button) findViewById(R.id.btn_9);
        btn_9.setOnClickListener(this);
        btndot=(Button) findViewById(R.id.btndot);
        btndot.setOnClickListener(this);
        btnadd=(Button) findViewById(R.id.btnadd);
        btnadd.setOnClickListener(this);
        btnsub=(Button) findViewById(R.id.btnsub);
        btnsub.setOnClickListener(this);
        btnmul=(Button) findViewById(R.id.btnmul);
        btnmul.setOnClickListener(this);
        btndiv=(Button) findViewById(R.id.btndiv);
        btndiv.setOnClickListener(this);
        btnclear=(Button) findViewById(R.id.btnclear);
        btnclear.setOnClickListener(this);
        btnequal=(Button) findViewById(R.id.btnequal);
        btnequal.setOnClickListener(this);

tres=(EditText) findViewById(R.id.editTextText);
        tres.setText("");
    }
    @Override
    public void onClick(View v){
        if(v.equals(btn_0))
            tres.append("0");

if(v.equals(btn_1))
            tres.append("1");

if(v.equals(btn_2))
            tres.append("2");

if(v.equals(btn_3))
            tres.append("3");

if(v.equals(btn_4))
            tres.append("4");

if(v.equals(btn_5))
            tres.append("5");

if(v.equals(btn_6))
            tres.append("6");

if(v.equals(btn_7))
            tres.append("7");

if(v.equals(btn_8))
            tres.append("8");
        if(v.equals(btn_9))
            tres.append("9");

if(v.equals(btn_0))
            tres.append("0");

if(v.equals(btndot))
            tres.append(".");

if(v.equals(btnadd))
            tres.append("+");
        if(v.equals(btnsub))
            tres.append("-");

if(v.equals(btnmul))
            tres.append("*");

if(v.equals(btndiv))
            tres.append("/");

if(v.equals(btnclear))
            tres.setText("");

if(v.equals(btnequal)){
            try{
                String data = tres.getText().toString();
                if(data.contains("/")){
                    String[] operands=data.split("/");
                    if(operands.length==2){
                        double op1=Double.parseDouble(operands[0]);

double op2=Double.parseDouble(operands[1]);
                        double result=op1/op2;
                        tres.setText(String.valueOf(result));
                    }
                }

if(data.contains("*")){
                    String[] operands=data.split("\\*");
                    if(operands.length==2){
                        double op1=Double.parseDouble(operands[0]);

double op2=Double.parseDouble(operands[1]);
                        double result=op1*op2;
                        tres.setText(String.valueOf(result));
                    }
                }

if(data.contains("+")){
                    String[] operands=data.split("\\+");
                    if(operands.length==2){
                        double op1=Double.parseDouble(operands[0]);

double op2=Double.parseDouble(operands[1]);
                        double result=op1+op2;
                        tres.setText(String.valueOf(result));
                    }
                }

if(data.contains("-")){
                    String[] operands=data.split("-");
                    if(operands.length==2){
                        double op1=Double.parseDouble(operands[0]);

double op2=Double.parseDouble(operands[1]);
                        double result=op1-op2;
                        tres.setText(String.valueOf(result));
                    }
                }
            }catch(NumberFormatException e){
                Toast.makeText(getApplicationContext(),"error input", Toast.LENGTH_LONG).show();
            }
        }

}
}

PROGRAM 2

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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">
<EditText android:id="@+id/username"
android:layout_width="wrap_content" android:layout_height="wrap_content" android:ems="10" android:inputType="textPersonName" android:hint="UserName" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.497" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.316" />

</android.support.constraint.ConstraintLayout>

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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=".sign_in">

</android.support.constraint.ConstraintLayout>

package com.example.signup;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity; import android.os.Bundle;
import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast;

import java.util.regex.Matcher; import java.util.regex.Pattern;

public class MainActivity extends AppCompatActivity {

EditText username,password; Button signUpBtn;

String regularExpr="^(?=.*[A-Z])(?=.*[a-z])(?=.*\\d)(?=.*[@$!])[A-Za-z\\d@$!]{8,}$";

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

username = findViewById(R.id.username); password = findViewById(R.id.password); signUpBtn = findViewById(R.id.signup);

signUpBtn.setOnClickListener(new View.OnClickListener() { @Override
public void onClick(View v) {
String uname = username.getText().toString(); String pwd = password.getText().toString();

if(validatePassword(pwd)){

Bundle bundle = new Bundle();

bundle.putString("username",uname); bundle.putString("password",pwd);

Intent intent = new Intent(MainActivity.this,sign_in.class);

intent.putExtras(bundle);

startActivity(intent);
}
else{
Toast.makeText(MainActivity.this, "Invaild Password", Toast.LENGTH_SHORT).show();
}
}
});
}
public boolean validatePassword(String pwd){ Pattern pattern = Pattern.compile(regularExpr); Matcher matcher = pattern.matcher(pwd); return matcher.matches();
}
}

package com.example.signup;

import android.support.v7.app.AppCompatActivity; import android.os.Bundle;
import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast;

public class sign_in extends AppCompatActivity {

EditText username,password; Button signInBtn;

int count=0;

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

username = findViewById(R.id.username); password = findViewById(R.id.password); signInBtn = findViewById(R.id.signin);

Bundle bundle = getIntent().getExtras();

String uname = bundle.getString("username"); String pwd = bundle.getString("password");

signInBtn.setOnClickListener(new View.OnClickListener() { @Override
public void onClick(View v) {
String user = username.getText().toString(); String pass = password.getText().toString();

if(user.equals(uname) && pass.equals(pwd)){
Toast.makeText(sign_in.this, "Success", Toast.LENGTH_SHORT).show();
}
else {
count++;
if (count >= 3) { signInBtn.setEnabled(false);
} else {
Toast.makeText(sign_in.this, "Failed", Toast.LENGTH_SHORT).show();
}
}
}
});
}
}

PROGRAM 3

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:gravity="center"
    tools:context=".MainActivity">

<Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"

android:background="#FFEB3B"
        android:text="CHANGE WALLPAPER" />
</LinearLayout>

package com.code.changewallpaper;

import androidx.appcompat.app.AppCompatActivity;

import android.app.WallpaperManager;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import java.io.IOException;
import java.util.Timer;
import java.util.TimerTask;

public class MainActivity extends AppCompatActivity {

int images[]=new int[]{
            R.drawable.hennaart1,
            R.drawable.palm,
            R.drawable.tattoo1,
            R.drawable.shabbu

};

Button btn;
    int i=0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

btn=findViewById(R.id.btn);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                new Timer().schedule(new ChangeWallpaper(),0,10000);
                WallpaperManager wallpaperManager=WallpaperManager.getInstance(getBaseContext());
                try{
                    wallpaperManager.setBitmap(BitmapFactory.decodeResource(getResources(),images[i]));
                    i++;
                    if(i==4){
                        i=0;
                    }
                }catch(IOException e){
                    e.printStackTrace();
                }
            }
        });

}
    class ChangeWallpaper extends TimerTask{
        @Override
        public void run(){
            WallpaperManager wallpaperManager=WallpaperManager.getInstance(getBaseContext());
            try{
                wallpaperManager.setBitmap(BitmapFactory.decodeResource(getResources(),images[i]));
                i++;
                if(i==4){
                    i=0;
                }
            }catch(IOException e){
                e.printStackTrace();
            }
        }
    }
}
        
        
        <uses-permission android:name="android.permission.SET_WALLPAPER"/>

PROGRAM 4

</androidx.constraintlayout.widget.ConstraintLayout>

package com.code.counterapp;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

private static final String TAG="thread";
    Handler mainHandler = new Handler();
    int count=0,i;
    int stopcount=0;
    boolean running=false;
    Button startbtn,stopbtn;
    TextView counterValue;
    void startThread(){
        NewThread nObj= new NewThread();
        nObj.start();
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

counterValue=findViewById(R.id.counterValue);
        startbtn=findViewById(R.id.startbtn);
        startbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                count=0;
                running=true;
                count=stopcount;
                startThread();
            }
        });

stopbtn=findViewById(R.id.stopbtn);
        stopbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                 running=false;
                 stopcount=count;
            }
        });

}
    class NewThread extends Thread{

@Override
        public void run(){
            while(running){

count++;
                mainHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        counterValue.setText(String.valueOf(count));
                    }
                });
                Log.d(TAG,"startThread"+i);
                try{
                    Thread.sleep(2000);
                }catch (InterruptedException e){
                    e.printStackTrace();
                }
            }
        }
    }
}

PROGRAM 5

Main java

package com.example.dataparser;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

Button xmlbtn, jsonbtn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.activity_main);
        xmlbtn = findViewById(R.id.xmlbtn); 
        jsonbtn = findViewById(R.id.jsonbtn);
        xmlbtn.setOnClickListener(new View.OnClickListener() { @Override
        public void onClick(View view) {
            Intent intent = new Intent(MainActivity.this,view.class);
            intent.putExtra("mode",1);
            startActivity(intent);
        }
        });
        jsonbtn.setOnClickListener(new View.OnClickListener() { @Override
        public void onClick(View view) {
            Intent intent = new Intent(MainActivity.this,view.class);
            intent.putExtra("mode",2);
            startActivity(intent);
        } });
    } }

View 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=".view">
    <TextView
        android:id="@+id/jsonPlaceHolder"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:textColor="#2196F3"
        android:textSize="25sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.482"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.555" />
    <TextView
        android:id="@+id/xmlPlaceHolder"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:textColor="#2196F3"
        android:textSize="25sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.482"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.394" />
    <TextView
        android:id="@+id/xmlHeading"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="XML Data"
        android:textColor="#F44336"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.478"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.213" />
    <TextView
        android:id="@+id/jsonHeading"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="JSON Data"
        android:textColor="#F44336"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.488"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.268" />
    <TextView
        android:id="@+id/textView6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Parse Data"
        android:textColor="#009688"
        android:textSize="34sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.473"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.066" />
</androidx.constraintlayout.widget.ConstraintLayout>

View java

package com.example.dataparser;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

import org.json.JSONException;
import org.json.JSONObject;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import java.io.IOException;
import java.io.InputStream;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

public class view extends AppCompatActivity {

int mode;
    TextView xmlPlaceHolder, jsonPlaceholder,xmlHeading,jsonHeading;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_view);
        mode = getIntent().getIntExtra("mode",0);
        xmlPlaceHolder = findViewById(R.id.xmlPlaceHolder);
        jsonPlaceholder = findViewById(R.id.jsonPlaceHolder);
        xmlHeading = findViewById(R.id.xmlHeading);
        jsonHeading = findViewById(R.id.jsonHeading);
        if(mode==1) {
            parseXML(); }
        if(mode==2) {
            parseJSON(); }
    }

public void parseJSON() {
        xmlPlaceHolder.setText("");
        xmlHeading.setText("");
        String stringData = null;
        try{
            InputStream inputStream = getAssets().open("input.json");

int size = inputStream.available();
            byte buffer[] = new byte[size];
            inputStream.read(buffer);
            stringData = new String(buffer);

Log.e("data","parseJSON: " +stringData);
            JSONObject jsonObject = new JSONObject(stringData);
            Log.e("data","parseJSON"+jsonObject);
            Log.e("data", "parseJSON:"+jsonObject.getClass().getName());

JSONObject cityObject = jsonObject.getJSONObject("City");
            String cityName = cityObject.getString("City-Name");
            String longitude = cityObject.getString("Longitude");
            String latitude = cityObject.getString("Latitude");
            String temperature = cityObject.getString("Temperature");
            String humidity = cityObject.getString("Humidity");
            Log.e("data","parseJSON:"+cityName);
            jsonPlaceholder.setText("City-Name - "+cityName+"\n");
            jsonPlaceholder.append("Longitude - "+longitude+"\n");
            jsonPlaceholder.append("Latitude - "+latitude+"\n");
            jsonPlaceholder.append("Temperature - "+temperature+"\n");
            jsonPlaceholder.append("Humidity - "+humidity+"\n");
        }
        catch (IOException e) {
            e.printStackTrace();
        } catch (JSONException e) {
            e.printStackTrace(); }
    }
    public void parseXML() {
        xmlPlaceHolder.setText("");
        jsonPlaceholder.setText("");
        jsonHeading.setText("");
        try{

InputStream inputStream = getAssets().open("input.xml");
            DocumentBuilderFactory documentBuilderFactory =
                    DocumentBuilderFactory.newInstance();
            DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
            Document document = documentBuilder.parse(inputStream);
            NodeList cityList = document.getElementsByTagName("City");
            for(int i=0;i<cityList.getLength();
                i++)
            {
                Node c = cityList.item(i);
                if(c.getNodeType() == Node.ELEMENT_NODE) {
                    Element city = (Element) c;

NodeList cityDetailList = city.getChildNodes();
                    for(int j=0;
                        j<cityDetailList.getLength();j++) {
                        Node n = cityDetailList.item(j);
                        if(n.getNodeType() == Node.ELEMENT_NODE)

{
                            Element cityDetail = (Element) n;
                            String tagValue = cityDetail.getTagName();
                            String value = cityDetail.getTextContent();
                            Log.e("data","parseXML"+value);
                            xmlPlaceHolder.append(tagValue+" - "+value);
                            xmlPlaceHolder.append("\n"); }
                    } }
            } }
        catch (IOException e) {
            e.printStackTrace();
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace(); }
    } }

Input xml

<?xml version="1.0"?>
<Records>
    <City>
        <City-Name>Mangalore</City-Name>
        <Longitude>78</Longitude>
        <Latitude>13</Latitude>
        <Temperature>30</Temperature>
        <Humidity>90%</Humidity> </City>
</Records>

Input json

{
  "City": {
    "City-Name": "Bengaluru",
    "Longitude": "78,",
    "Latitude": "13",
    "Temperature": "30",
    "Humidity": "90%"
  }
}

PROGRAM 6

</androidx.constraintlayout.widget.ConstraintLayout>

package com.code.texttospeechapp;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.speech.tts.TextToSpeech;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import java.util.Locale;

public class MainActivity extends AppCompatActivity {

EditText enterValue;
    Button btnspeak;
    TextToSpeech textToSpeech;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

btnspeak=findViewById(R.id.btnspeak);
        enterValue=findViewById(R.id.enterValue);

textToSpeech=new TextToSpeech(MainActivity.this, new TextToSpeech.OnInitListener() {
            @Override
            public void onInit(int status) {
                if(status==TextToSpeech.SUCCESS){
                    textToSpeech.setLanguage(Locale.ENGLISH);
                }else{
                    Log.e("failed","onInit:failed");
                }
            }
        });
        btnspeak.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String text=enterValue.getText().toString();
                Toast.makeText(getBaseContext(),text,Toast.LENGTH_LONG).show();
                textToSpeech.speak(text,TextToSpeech.QUEUE_FLUSH,null);
            }
        });

}
}

PROGRAM 7

package com.code.phonedialerapp;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

Button btn_0,btn_1,btn_2,btn_3,btn_4,btn_5,btn_6,btn_7,btn_8,btn_9;
    Button btn_call,btn_save,btn_remove,btn_star,btn_hash;
    EditText display;

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

btn_0=findViewById(R.id.btn_0);

btn_0=findViewById(R.id.btn_0);
        btn_1=findViewById(R.id.btn_1);
        btn_2=findViewById(R.id.btn2);
        btn_3=findViewById(R.id.btn_3);
        btn_4=findViewById(R.id.btn_4);
        btn_5=findViewById(R.id.btn_5);
        btn_6=findViewById(R.id.btn_6);
        btn_7=findViewById(R.id.btn_7);
        btn_8=findViewById(R.id.btn_8);
        btn_9=findViewById(R.id.btn_9);
        btn_call=findViewById(R.id.btn_call);
        btn_save=findViewById(R.id.btn_save);
        btn_remove=findViewById(R.id.btn_remove);
        btn_star=findViewById(R.id.btn_star);
        btn_hash=findViewById(R.id.btn_hash);

display=findViewById(R.id.display);

btn_0.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.append("0");
            }
        });
        btn_1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.append("1");
            }
        });
        btn_2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.append("2");
            }
        });
        btn_3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.append("3");
            }
        });
        btn_4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.append("4");
            }
        });
        btn_5.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.append("5");
            }
        });
        btn_6.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.append("6");
            }
        });
        btn_7.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.append("7");
            }
        });
        btn_8.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.append("8");
            }
        });
        btn_9.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.append("9");
            }
        });
        btn_star.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.append("*");
            }
        });
        btn_hash.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                display.append("#");
            }
        });

btn_save.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String data=display.getText().toString();
                Intent intent = new Intent(ContactsContract.Intents.Insert.ACTION);
                intent.setType(ContactsContract.RawContacts.CONTENT_TYPE);
                intent.putExtra(ContactsContract.Intents.Insert.NAME,"Username");
                intent.putExtra(ContactsContract.Intents.Insert.PHONE,data);
                startActivity(intent);

}
        });

btn_remove.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String data = display.getText().toString();
                if (data.length() > 0) {
                    String val = data.substring(0, data.length() - 1);
                    display.setText(val);
                } else
                    display.setText("");
            }
        });
        btn_call.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String data=display.getText().toString();
                Intent intent = new Intent(Intent.ACTION_DIAL);
                intent.setData(Uri.parse("tel"+data));

startActivity(intent);

}
        });

}
}

PROGRAM 1

PROGRAM 2

PROGRAM 3

PROGRAM 4

PROGRAM 5

PROGRAM 6

PROGRAM 7

PROGRAM 8