Retrieve contacts in Android. Here we are fetching all the contacts with user number and mobile. You need to add READ_CONTACTS permission Manifest file. Reference: http://www.techiesatish.com/retrieving-contacts-in-listview-in-android/

ContactsActivity.java

<?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">

    <ListView
        android:id="@+id/lv_Contacts"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:layout_marginBottom="0dp" />

</android.support.constraint.ConstraintLayout>





public class ContactsActivity extends AppCompatActivity {
    ListView lvContacts;
    String TAG = ContactsActivity.class.getSimpleName();
    ArrayList<String> mContacts;
    ArrayAdapter arrayAdapter;
    public static final int PERMISSION_REQUEST_CONTACT = 103;
    boolean hasPermissionContact;
    String userName,MobileNo;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_contacts);
        lvContacts = findViewById(R.id.lv_Contacts);
        mContacts = new ArrayList<>();
        arrayAdapter = new ArrayAdapter<String>(
                ContactsActivity.this,
                android.R.layout.simple_list_item_1, android.R.id.text1, mContacts);
        askForPermission();
        lvContacts.setAdapter(arrayAdapter);

    }

    private void askForPermission() {
        hasPermissionContact = (ContextCompat.checkSelfPermission(getApplicationContext(), android.Manifest.permission.READ_CONTACTS) == PackageManager.PERMISSION_GRANTED);
        if (!hasPermissionContact) {
            ActivityCompat.requestPermissions(ContactsActivity.this, new String[]{android.Manifest.permission.READ_CONTACTS}, PERMISSION_REQUEST_CONTACT);
        }else{
            getContacts();
        }

    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {

            case PERMISSION_REQUEST_CONTACT: {
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    Toast.makeText(ContactsActivity.this, "Permission Granted.", Toast.LENGTH_SHORT).show();
                    getContacts();
                    runOnUiThread(new Runnable() {

                        @Override
                        public void run() {
                            lvContacts.setAdapter(arrayAdapter);
                        }
                    });


                } else {
                    Toast.makeText(ContactsActivity.this, "Permission Denied", Toast.LENGTH_LONG).show();
                }
            }

        }

    }


    public void  getContacts() {

        Cursor cursor = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null, null, null);

        while (cursor.moveToNext()) {

            userName = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));

            MobileNo = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));

            Log.e(TAG, "contacts " + userName + " " + MobileNo);

            Collections.sort(mContacts, String.CASE_INSENSITIVE_ORDER);  //Sorting of contacts

            mContacts.add(userName + " " + "\n" + " " + MobileNo);

        }

        cursor.close();

    }

}