dialer.java

package com.example.dialer;

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 callBtn,saveBtn,deleteBtn;
    EditText phone;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        callBtn = findViewById(R.id.call);
        saveBtn = findViewById(R.id.save);
        deleteBtn = findViewById(R.id.delete);
        phone = findViewById(R.id.num);

        callBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String phoneNo = phone.getText().toString();
                Intent intent = new Intent(Intent.ACTION_DIAL);
                intent.setData(Uri.parse("tel:"+phoneNo));
                startActivity(intent);
            }
        });

        saveBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String phoneNo = phone.getText().toString();
                Intent intent = new Intent(Intent.ACTION_INSERT);
                intent.setType(ContactsContract.Contacts.CONTENT_TYPE);
                intent.putExtra(ContactsContract.Intents.Insert.PHONE,phoneNo);
                startActivity(intent);
            }
        });

        deleteBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                phone.setText("");
            }
        });
    }
}