tugas aritmatika

MainActivity 

package com.example.projectirsyad;

import androidx.appcompat.app.AppCompatActivity;

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

public class MainActivity extends AppCompatActivity {
    EditText bil1,bil2;
    TextView Hasil;


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

    }
    public void kirim(View view){
        EditText bil1 = findViewById(R.id.Bil1);
        EditText  bil2 = findViewById(R.id.Bil2);
        EditText  bil3 = findViewById(R.id.Bil3);
        EditText   bil4 = findViewById(R.id.Bil4);
        EditText Nama = findViewById(R.id.nama);
        TextView  Name = findViewById(R.id.name);
        TextView Hasil = findViewById(R.id.hasil);
        TextView Ket = findViewById(R.id.ket);

        float Bil1 = Integer.parseInt(bil1.getText().toString());
        float Bil2 = Integer.parseInt(bil2.getText().toString());
        float Bil3 = Integer.parseInt(bil3.getText().toString());
        float Bil4 = Integer.parseInt(bil4.getText().toString());
        String nama = Nama.getText().toString();
        String name = Nama.getText().toString();
        String ket =null;
        double hasil = (Bil1*0.1)+(Bil2*0.2)+(Bil3*0.3)+(Bil4*0.4);



        if (hasil > 80){
            ket = "Memuaskan";
        }else if (hasil >70){
            ket = "Cukup";
        }else if (hasil > 65){
            ket = "Kurang";
        }else{
            ket = "Gagal";
        }
        Name.setText("Nama : "+(name));
        Hasil.setText("Hasil AKhir : "+(hasil));
        Ket.setText("Keterangan : "+(ket));
    }

}

activity_main

<?xml version="1.0" encoding="utf-8"?>

<androidx.constraintlayout.widget.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"
    tools:context=".MainActivity">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:orientation="vertical"
        app:layout_constraintTop_toTopOf="parent"
        android:padding="10dp">
        <EditText
            android:id="@+id/nama"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="15dp"
            android:hint="Nama Siswa...."/>
        <EditText
            android:id="@+id/Bil1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="15dp"
            android:hint="Input Bilangan 1...."/>
        <EditText
            android:id="@+id/Bil2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="15dp"
            android:hint="Input Bilangan 2...."/>
        <EditText
            android:id="@+id/Bil3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="15dp"
            android:hint="Input Bilangan 3...."/>
        <EditText
            android:id="@+id/Bil4"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="15dp"
            android:hint="Input Bilangan 4...."/>
        <Button
            android:id="@+id/Kirim"
            android:onClick="kirim"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@color/teal_700"
            android:text="Total"
            android:layout_margin="5dp"
            android:textColor="@color/white"/>
        <TextView
            android:id="@+id/name"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Nama :"
            android:textSize="20dp"
            android:layout_marginTop="40dp"/>
        <TextView
            android:id="@+id/hasil"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Hasil :"
            android:textSize="20dp"
            android:layout_marginTop="40dp"/>
        <TextView
            android:id="@+id/ket"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Keterangan :"
            android:textSize="20dp"
            android:layout_marginTop="40dp"/>

    </LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>