Final

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.provider.MediaStore;
import android.provider.Telephony;
import android.support.annotation.NonNull;
import android.support.annotation.RequiresApi;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Toast;

import static android.os.Build.VERSION;
import static android.os.Build.VERSION_CODES;

public class MainActivity extends AppCompatActivity {
    private static final int CAMERA_REQUEST_CODE = 100;
    private static final int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE=1;
    String smsText = "This is a test message";

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

    @RequiresApi(api = VERSION_CODES.M)
    public void openCamera(View view) {

        if (checkSelfPermission(Manifest.permission.CAMERA)
                != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{Manifest.permission.CAMERA},
                    CAMERA_REQUEST_CODE);
        }else { // Do stuff here for Action Image Capture.
            Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

            // start the image capture Intent
            startActivityForResult(intent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);}
    }

    public void openMessage(View view) {
        if (VERSION.SDK_INT >= VERSION_CODES.KITKAT) //At least KitKat
        {
            String defaultSmsPackageName = Telephony.Sms.getDefaultSmsPackage(getApplicationContext()); //Need to change the build to API 19

            Intent sendIntent = new Intent(Intent.ACTION_SEND);
            sendIntent.setType("text/plain");
            sendIntent.putExtra(Intent.EXTRA_TEXT, smsText);

            if (defaultSmsPackageName != null)//Can be null in case that there is no default, then the user would be able to choose any app that support this intent.
            {
                sendIntent.setPackage(defaultSmsPackageName);
            }
            getApplicationContext().startActivity(sendIntent);

        } else //For early versions, do what worked for you before.
        {
            Intent sendIntent = new Intent(Intent.ACTION_VIEW);
            sendIntent.setData(Uri.parse("sms:"));
            sendIntent.putExtra("sms_body", smsText);
            getApplicationContext().startActivity(sendIntent);
        }

    }

    public void openContacts(View view) {
        Intent intent = new Intent(Intent.ACTION_PICK);
        intent.setType(ContactsContract.Contacts.CONTENT_TYPE);
        startActivityForResult(intent, 10011);
    }

    public void openCalendar(View view) {
        Intent calendarIntent = new Intent(Intent.ACTION_EDIT);
        calendarIntent.setType("vnd.android.cursor.item/event");
        calendarIntent.putExtra("title", "Title");
        calendarIntent.putExtra("beginTime", 2000);
        calendarIntent.putExtra("endTime", 5000);
        calendarIntent.putExtra("description", "Description");

        startActivity(calendarIntent);

    }

    public void openBrowser(View view) {
        Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com"));
        startActivity(browserIntent);
    }

    @Override

    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {

        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        if (requestCode == CAMERA_REQUEST_CODE) {

            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                Toast.makeText(this, "Camera permission granted.", Toast.LENGTH_LONG).show();

                // Do stuff here for Action Image Capture.
                Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

                // start the image capture Intent
                startActivityForResult(intent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);

            } else {

                Toast.makeText(this, "Camera permission denied.", Toast.LENGTH_LONG).show();

            }

        }
    }
}