9.23作业

package com.example.myapplication;

import android.annotation.SuppressLint;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.material.bottomnavigation.BottomNavigationView;

import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.AppBarConfiguration;
import androidx.navigation.ui.NavigationUI;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private TextView result;
    private Button btn1;
    private Button btn2;
    private Button btn3;
    private Button btn4;
    private EditText edit1;
    private EditText edit2;
    public MainActivity() {
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        BottomNavigationView navView = findViewById(R.id.nav_view);
        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        AppBarConfiguration appBarConfiguration = new AppBarConfiguration.Builder(
                R.id.navigation_home, R.id.navigation_dashboard, R.id.navigation_notifications)
                .build();
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
        NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration);
        NavigationUI.setupWithNavController(navView, navController);
            btn1 = (Button) findViewById(R.id.btn111);
          btn2 = (Button) findViewById(R.id.btn222);
          btn3 = (Button) findViewById(R.id.btn333);
          btn4 = (Button) findViewById(R.id.btn444);
         result=(TextView) findViewById(R.id.result);
           edit1=(EditText) findViewById(R.id.edi1);
           edit2=(EditText) findViewById(R.id.edi2);
        btn1.setOnClickListener(this);
        btn2.setOnClickListener(this);
        btn3.setOnClickListener(this);
        btn4.setOnClickListener(this);
    }
//    public  void  aaa(View view){
//        Toast.makeText(MainActivity.this, "按钮被点击",0).show();
//    }

    @Override
    public void onClick(View v) {  final AlertDialog.Builder alterDiaglog = new AlertDialog.Builder(MainActivity.this);

        alterDiaglog.setTitle("简单的dialog");//文字
        alterDiaglog.setMessage("是否计算");//提示消息
        //积极的选择
        alterDiaglog.setPositiveButton("是", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                Toast.makeText(MainActivity.this,"计算成功",Toast.LENGTH_SHORT).show();
            }
        });
        //消极的选择
        alterDiaglog.setNegativeButton("否", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                Toast.makeText(MainActivity.this,"结束",Toast.LENGTH_SHORT).show();
                MainActivity.this.finish();
            }
        });
        //中立的选择
        alterDiaglog.setNeutralButton("不进行计算", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                Toast.makeText(MainActivity.this,"不计算",Toast.LENGTH_SHORT).show();
            }
        });


        //显示
        alterDiaglog.show();





        int num1 =Integer.parseInt(edit1.getText().toString());
        int num2 =Integer.parseInt(edit2.getText().toString());
        int result1 =0;
        System.out.println(num1);
        System.out.println(num2);
        switch (v.getId()) {
            case R.id.btn111:
                result1=num1 + num2;
                System.out.println(result);
                break;
            case R.id.btn222:
                result1=num1 - num2;
                break;
            case R.id.btn333:
                result1=num1 * num2;
                break;
            case R.id.btn444:
                result1=num1 / num2;
                break;
        }
        result.setText(result1+"");

}

}

<?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"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingTop="?attr/actionBarSize">

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/nav_view"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="0dp"
        android:layout_marginEnd="0dp"
        android:background="?android:attr/windowBackground"
       android:layout_alignParentBottom="true"/>
    <TextView
        android:id="@+id/text_notifications"
        android:layout_width="490dp"
        android:layout_height="46dp"
        android:layout_alignParentBottom="true"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:textAlignment="center"
        android:textSize="20sp" />

    <EditText
        android:id="@+id/edi1"
        android:layout_width="600dp"
        android:layout_height="80dp"
        />
    <EditText
        android:id="@+id/edi2"
        android:layout_width="600dp"
        android:layout_height="80dp"
        android:layout_below="@+id/edi1"

        />

    <Button
        android:id="@+id/btn111"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/edi2"
        android:layout_marginLeft="20dp"
        android:layout_marginTop="50dp"
        android:text="+" />

    <Button
        android:id="@+id/btn222"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/edi2"
        android:layout_marginTop="50dp"
        android:text="-"
        android:layout_toRightOf="@+id/btn111"

        />
    <Button
        android:id="@+id/btn333"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/edi2"
        android:text="*"
        android:layout_marginTop="50dp"
        android:layout_toRightOf="@+id/btn222"

        />
    <Button
        android:id="@+id/btn444"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/edi2"
        android:layout_marginTop="50dp"
        android:text="/"
        android:layout_toRightOf="@+id/btn333"

        />
    <TextView
        android:id="@+id/te"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="计算结果"
        android:textSize="40dp"
        android:layout_marginTop="50dp"
        android:layout_below="@+id/btn444"
        />
    <TextView
        android:id="@+id/result"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="40dp"
        android:layout_below="@+id/te"
        android:layout_marginTop="50dp"
        />
    <fragment
        android:id="@+id/nav_host_fragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toTopOf="@id/nav_view"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/mobile_navigation" />

</RelativeLayout>