I have been struggling in this for 2days, can anybody give a suggestion on how to solve it?
This is my WhatsApp2 activity...
public class WhatsApp2 extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
}
public void whatsappSend(){
    try {
        String toNumber = "xxxxxxxxxx";
        Intent sendIntent = new Intent(Intent.ACTION_SENDTO,    Uri.parse("smsto:" + "" + toNumber+ "?body=" + ""));
        sendIntent.setPackage("com.whatsapp");
        startActivity(sendIntent);
    }
    catch (Exception e){
        e.printStackTrace();
    }
  }
}
And I am trying to call the whatsappSend() from another activity like this...
public class MainActivity extends  AppCompatActivity {
    public WhatsApp2 whatsApp2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 }
 public void whatsapp(View view) {
     whatsApp2 = new WhatsApp2();
     whatsApp2.whatsappSend();
  }
 }
It Catch an exception error in the WhatsApp2 class as:
java.lang.NullPointerException: Attempt to invoke virtual method 'android.app.ActivityThread$ApplicationThread android.app.ActivityThread.getApplicationThread()' on a null object reference
 
     
    