package com.example.myapplication4;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
    public RadioGroup radioGroup;
    EditText one1;
    EditText two1;
    TextView jg;
    Integer d1;
    Integer d2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        radioGroup=findViewById(R.id.rg);

        radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup radioGroup, int i) {
                switch (i){
                    case R.id.jia:jia();break;
                    case R.id.jian:jian();break;
                    case R.id.cheng:cheng();break;
                    case R.id.chu:chu();break;
                }
            }
        });

    }

    private void chu(){
        jg=findViewById(R.id.tv1);
        two1=findViewById(R.id.two);
        String on=one1.getText().toString();
        String tw=two1.getText().toString();
        d1=Integer.valueOf(on);
        d2=Integer.valueOf(tw);
        if (d2==0||d1==0) {
            Toast.makeText(MainActivity.this, "除数不能为0", Toast.LENGTH_SHORT).show();
        }else {
            String st = Integer.toString(d1 / d2);
            jg.setText(st);
        }
    }
    public void cheng(){
        jg=findViewById(R.id.tv1);
        one1=findViewById(R.id.one);
        two1=findViewById(R.id.two);
        String on=one1.getText().toString();
        String tw=two1.getText().toString();
        d1=Integer.valueOf(on);
        d2=Integer.valueOf(tw);
        String st=Integer.toString(d1*d2);
        jg.setText(st);
    }
    public void jia() {
        jg = findViewById(R.id.tv1);
        one1 = findViewById(R.id.one);
        two1 = findViewById(R.id.two);
        String on = one1.getText().toString();
        String tw = two1.getText().toString();
        d1 = Integer.valueOf(on);
        d2 = Integer.valueOf(tw);
        String st = Integer.toString(d1 + d2);
        jg.setText(st);
    }
    public void jian(){
        jg=findViewById(R.id.tv1);
        one1=findViewById(R.id.one);
        two1=findViewById(R.id.two);
        String on=one1.getText().toString();
        String tw=two1.getText().toString();
        d1=Integer.valueOf(on);
        d2=Integer.valueOf(tw);
        String st=Integer.toString(d1-d2);
        jg.setText(st);
    }

    public void qkz(View view){
        jg.setText("");
        one1.setText("");
        two1.setText("");
    }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#777777"
    tools:context=".MainActivity">
    <LinearLayout
        android:id="@+id/line1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="100dp"
        android:background="#FFFFFF"
        android:orientation="horizontal"
        >

        <TextView

            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="输入第一个数"
            android:textColor="#1B1B1B" />

        <EditText
            android:id="@+id/one"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="第一个数"
            android:textColorHint="#1CB9B3">

        </EditText>

    </LinearLayout>




    <LinearLayout
        android:id="@+id/line2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="150dp"
        android:background="#FFFFFF"
        android:orientation="horizontal">

        <TextView

            android:layout_width="wrap_content"
            android:layout_height="wrap_content"

            android:text="输入第二个数"
            android:textColor="#1B1B1B" />

        <EditText
            android:id="@+id/two"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="第二个数"
            android:textColorHint="#1CB9B3"
            />


    </LinearLayout>

    <RadioGroup
        android:id="@+id/rg"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:layout_below="@id/line2"
        android:layout_marginTop="80dp"
        >
        <RadioButton
            android:id="@+id/jia"
            android:text="+"
            android:layout_weight="1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>
        <RadioButton
            android:id="@+id/jian"
            android:text="-"
            android:layout_weight="1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>
        <RadioButton
            android:id="@+id/cheng"
            android:text="*"
            android:layout_weight="1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>

        <RadioButton
            android:id="@+id/chu"
            android:layout_width="124dp"
            android:layout_height="wrap_content"
            android:text="/" />
    </RadioGroup>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="400dp"
        android:background="#FFFFFF"
        android:orientation="horizontal">
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginRight="20dp"
            android:layout_marginLeft="20dp"
            android:text="清除"
            android:onClick="qkz"
            android:textSize="25dp"/>

    </LinearLayout>

   <TextView
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:layout_centerHorizontal="true"
       android:layout_centerVertical="true"
       android:id="@+id/tv1"
       >

   </TextView>
</RelativeLayout>