finds max value user input and generates random number between user inputs

maxrandom.java

package com.example.deniz.app9;

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.ImageButton;
import android.widget.TextView;
import android.widget.ViewSwitcher;

import java.security.SecureRandom;

public class MainActivity extends AppCompatActivity {

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


        final EditText edtNum1 = (EditText) findViewById(R.id.edtNum1);
        final EditText edtNum2 = (EditText) findViewById(R.id.edtNum2);
        final EditText edtNum3 = (EditText) findViewById(R.id.edtNum3);
        final EditText edtmax =(EditText) findViewById(R.id.edtmax);
        final EditText edtmin =(EditText) findViewById(R.id.edtmin);

        final TextView txtResult = (TextView) findViewById(R.id.txtResult);
        final TextView txtrandom = (TextView) findViewById(R.id.txtrandom);
        final TextView txtold = (TextView) findViewById(R.id.txtold);

        final ImageButton btndelete = (ImageButton) findViewById(R.id.btndelete);
        Button btnMax = (Button) findViewById(R.id.btnMax);
        Button btnRandom = (Button)findViewById(R.id.btnRandom);

        btnMax.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                double num1 = Double.parseDouble(edtNum1.getText().toString());
                double num2 = Double.parseDouble(edtNum2.getText().toString());
                double num3 = Double.parseDouble(edtNum3.getText().toString());
                double result = getMax(num1,num2,num3);
                txtResult.setText(result +"");


            }
        });


        btnRandom.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int max = 10;
                int min = 0;
                if(!edtmax.getText().toString().isEmpty()){
                    max = Integer.parseInt(edtmax.getText().toString());
                }
                else
                    edtmax.setText("10");
                if(!edtmin.getText().toString().isEmpty()){
                    min = Integer.parseInt(edtmin.getText().toString());
                }
                else
                    edtmin.setText("0");
                if(min>max){
                    int tmp = max;
                    max = min;
                    min = tmp;
                }
                SecureRandom securerandomnum = new SecureRandom();
                String oldnum = txtrandom.getText().toString();
                txtold.setText(oldnum);

                int randomnum = min + securerandomnum.nextInt((max-min+1));

                txtrandom.setText(randomnum + "");

                btndelete.setVisibility(View.VISIBLE);
            }
        });

        btndelete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                ((EditText) findViewById(R.id.edtmax)).getText().clear();
                ((EditText) findViewById(R.id.edtmin)).getText().clear();
                txtrandom.setText("Secure Random Numbers");
                txtResult.setText("Result:");
                btndelete.setVisibility(View.GONE);

            }
        });
    }

    public double getMax(double num1,double num2,double num3){

        double result=num1;

        if(result < num2)
            result = num2;
        if(result < num3)
            result = num3;

        return result;
    }
}