Trabalho com App de descontos da feira.

DescontaoApp.java

package projetodesenvolvedor.usuario.app.trabalhopratico;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

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

    public void calcPrice(View view) {
        TextView edtPeso = (TextView)findViewById(R.id.edtPeso);
        RadioGroup rdgpFruits = (RadioGroup)findViewById(R.id.rdgpFruits);
        RadioButton selectedRdFruit = (RadioButton)findViewById(rdgpFruits.getCheckedRadioButtonId());
        Toast toast;

        double valor;
        double peso = Double.valueOf(edtPeso.getText().toString());
        String selectedFruitName = selectedRdFruit.getText().toString();

        if (selectedFruitName.compareToIgnoreCase("morango") == 0) {
            valor = peso * (peso > 10.0 ? 4 : 5);
            toast = Toast.makeText(this, String.valueOf(valor), Toast.LENGTH_LONG);
        } else if (selectedFruitName.compareToIgnoreCase("maçã") == 0) {
            valor = peso * (peso > 10.0 ? 1 : 2);
            toast = Toast.makeText(this, String.valueOf(valor), Toast.LENGTH_LONG);
        } else if (selectedFruitName.compareToIgnoreCase("banana") == 0) {
            valor = peso * (peso > 10.0 ? 1.5 : 1.8);
            toast = Toast.makeText(this, String.valueOf(valor), Toast.LENGTH_LONG);
        } else if(selectedFruitName.compareToIgnoreCase("abacate") == 0) {
            valor = peso * (peso > 10.0 ? 7.5 : 8);
            toast = Toast.makeText(this, String.valueOf(valor), Toast.LENGTH_LONG);
        } else if(selectedFruitName.compareToIgnoreCase("laranja") == 0) {
            valor = peso * (peso > 10.0 ? 2.5 : 3.5);
            toast = Toast.makeText(this, String.valueOf(valor), Toast.LENGTH_LONG);
        } else {
            toast = Toast.makeText(this, "Escolha um fruta válida", Toast.LENGTH_LONG);
        }

        toast.show();
    }

    public void clean(View view) {
        TextView edtPeso = (TextView)findViewById(R.id.edtPeso);
        RadioGroup rdgpFruits = (RadioGroup)findViewById(R.id.rdgpFruits);

        edtPeso.setText("");
        rdgpFruits.clearCheck();
    }
}

DescontaoApp.xml

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

    <TextView
        android:id="@+id/txtDescription"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/edtPeso"
        android:layout_centerHorizontal="true"
        android:text="Informe a quantidade de quilos:"
        android:textColor="@android:color/holo_blue_dark"
        android:textSize="14sp"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/txtTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="62dp"
        android:text="Descontão App"
        android:textColor="@android:color/holo_red_dark"
        android:textSize="24sp"
        android:textStyle="bold" />

    <RadioGroup
        android:id="@+id/rdgpFruits"
        android:layout_width="230dp"
        android:layout_height="179dp"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="104dp">

        <RadioButton
            android:id="@+id/rdFruit1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Maçã" />

        <RadioButton
            android:id="@+id/rdFruit2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Morango" />

        <RadioButton
            android:id="@+id/rdFruit3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Banana" />

        <RadioButton
            android:id="@+id/rdFruit4"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Abacate" />

        <RadioButton
            android:id="@+id/rdFruit5"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Laranja" />
    </RadioGroup>

    <EditText
        android:id="@+id/edtPeso"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="143dp"
        android:ems="10"
        android:hint="digite aqui"
        android:inputType="textPersonName" />

    <Button
        android:id="@+id/btnClean"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignEnd="@+id/edtPeso"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="88dp"
        android:onClick="clean"
        android:text="Limpar" />

    <Button
        android:id="@+id/btnCalc"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignStart="@+id/edtPeso"
        android:layout_alignTop="@+id/btnClean"
        android:onClick="calcPrice"
        android:text="Calcular" />

</RelativeLayout>