JAVA file for an fair a trip app

package com.example.shishu;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
EditText e1;
TextView t1;
Button b1;
int dis;
float total;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        e1 =(EditText)findViewById(R.id.e1);
        t1 =(TextView)findViewById(R.id.t1);
        b1 = (Button)findViewById(R.id.b1);

        b1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dis = Integer.parseInt(e1.getText().toString());

                if(dis <= 50) {
                    total = dis*1;
                    t1.setText(String.valueOf(total));
                }


                if(dis>=50 && dis<=150){
                    total=50+(dis-50)*2;
                    t1.setText(String.valueOf(total));
                }
                if(dis>=151 && dis<=2550){
                    total=50+200+(dis-150)*3;
                    t1.setText(String.valueOf(total));
                }
                if(dis>250){
                    total=50+200+300+(dis-250)*4;
                    t1.setText(String.valueOf(total));
                }
            }
        });

    }
}