用Android studio实现简易计算器功能

作者：晴笑歌时间：2021-07-31 21:06:13　

用Android studio做一个简易计算器，供大家参考，具体内容如下

长话短说，先建立一个Android项目；

创建完成后打开activity_main.xml，构建我们的应用界面，输入以下代码：

<?xml version="1.0" encoding="utf-8"?>
<GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:rowCount="6"
android:columnCount="4"
>

<EditText
android:id="@+id/edit"
android:layout_width="350dp"
android:layout_height="wrap_content"
android:layout_columnSpan="4"
android:layout_marginLeft="4px"
android:gravity="left"
android:textSize="50dp" />

<Button
android:id="@+id/clear"
android:layout_width="353dp"
android:layout_height="wrap_content"
android:layout_columnSpan="4"
android:text="清除"
android:textSize="26sp" />

<Button
android:id="@+id/btn1"
android:text="1"
android:textSize="26sp" />

<Button
android:id="@+id/btn2"
android:text="2"
android:textSize="26sp" />

<Button
android:id="@+id/btn3"
android:text="3"
android:textSize="26sp" />

<Button
android:id="@+id/jia"
android:text="+"
android:textSize="26sp" />

<Button
android:id="@+id/btn4"
android:text="4"
android:textSize="26sp" />

<Button
android:id="@+id/btn5"
android:text="5"
android:textSize="26sp" />

<Button
android:id="@+id/btn6"
android:text="6"
android:textSize="26sp" />

<Button
android:id="@+id/jian"
android:text="-"
android:textSize="26sp" />

<Button
android:id="@+id/btn7"
android:text="7"
android:textSize="26sp" />

<Button
android:id="@+id/btn8"
android:text="8"
android:textSize="26sp" />

<Button
android:id="@+id/btn9"
android:text="9"
android:textSize="26sp" />

<Button
android:id="@+id/cheng"
android:text="*"
android:textSize="26sp" />

<Button
android:id="@+id/dian"
android:text="."
android:textSize="26sp" />

<Button
android:id="@+id/btn0"
android:text="0"
android:textSize="26sp" />

<Button
android:id="@+id/sum"
android:text="="
android:textSize="26sp" />

<Button
android:id="@+id/chu"
android:text="/"
android:textSize="26sp" />

完成后再找到Mainactivity.java，输入以下代码：

package com.example.a00_ff_59_7f_7e_dc_54_3;

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

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

Button btn1, btn2, btn3, btn4, btn5, btn6, btn7, btn8, btn9, btn0; // 数字按钮
Button jia, jian, cheng, chu, dian, sum, clear;// +号
EditText edit; // 显示文本

private String ss = "";

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

// 获取页面上的控件
btn1 = (Button) findViewById(R.id.btn1);
btn2 = (Button) findViewById(R.id.btn2);
btn3 = (Button) findViewById(R.id.btn3);
btn4 = (Button) findViewById(R.id.btn4);
btn5 = (Button) findViewById(R.id.btn5);
btn6 = (Button) findViewById(R.id.btn6);
btn7 = (Button) findViewById(R.id.btn7);
btn8 = (Button) findViewById(R.id.btn8);
btn9 = (Button) findViewById(R.id.btn9);
btn0 = (Button) findViewById(R.id.btn0);
jia = (Button) findViewById(R.id.jia);
jian = (Button) findViewById(R.id.jian);
cheng = (Button) findViewById(R.id.cheng);
chu = (Button) findViewById(R.id.chu);
sum = (Button) findViewById(R.id.sum);
dian = (Button) findViewById(R.id.dian);
clear = (Button) findViewById(R.id.clear);
edit = (EditText) findViewById(R.id.edit);

// 按钮的单击事件
btn1.setOnClickListener(new Click());
btn2.setOnClickListener((View.OnClickListener) new Click());
btn3.setOnClickListener(new Click());
btn4.setOnClickListener(new Click());
btn5.setOnClickListener(new Click());
btn6.setOnClickListener(new Click());
btn7.setOnClickListener(new Click());
btn8.setOnClickListener(new Click());
btn9.setOnClickListener(new Click());
btn0.setOnClickListener(new Click());
jia.setOnClickListener(new Click());
jian.setOnClickListener(new Click());
cheng.setOnClickListener(new Click());
chu.setOnClickListener(new Click());
sum.setOnClickListener(new Click());
dian.setOnClickListener(new Click());
clear.setOnClickListener(new Click());
edit.setOnClickListener(new Click());
}

// 设置按钮点击后的监听
class Click implements View.OnClickListener {
public void onClick(View v) {
switch (v.getId()) { //switch循环获取点击按钮后的值
case R.id.clear: {
ss = "";
edit.setText(ss);
}
break;

case R.id.btn0: {
ss += "0";
edit.setText(ss);
}
break;
case R.id.btn1: {
ss += "1";
edit.setText(ss);
}
break;
case R.id.btn2: {
ss += "2";
edit.setText(ss);
}
break;

case R.id.btn3: {
ss += "3";
edit.setText(ss);
}
break;
case R.id.btn4: {
ss += "4";
edit.setText(ss);
}
break;
case R.id.btn5: {
ss += "5";
edit.setText(ss);
}
break;

case R.id.btn6: {
ss += "6";
edit.setText(ss);
}
break;
case R.id.btn7: {
ss += "7";
edit.setText(ss);
}
break;
case R.id.btn8: {
ss += "8";
edit.setText(ss);
}
break;
case R.id.btn9: {
ss += "0";
edit.setText(ss);
}
break;
case R.id.dian: {
if (ss.length() == 0 || ss.indexOf(" ") == ss.length() - 3 || ss.lastIndexOf(".") > ss.indexOf(" ")) {
break;
} else {
ss += ".";
edit.setText(ss);
}
}
break;
case R.id.jia: {
if (ss.length() == 0) {
break;
}
if (ss.contains(" ")) {
if (ss.indexOf(" ") == ss.length() - 3 || ss.indexOf(" ") == ss.length() - 2 || ss.indexOf(" ") == ss.length() - 1)
break;
getResult();
}

ss += " ＋ ";
edit.setText(ss);
}
break;
case R.id.jian: {
if (ss.length() == 0) {
break;
}
if (ss.contains(" ")) {
if (ss.indexOf(" ") == ss.length() - 3 || ss.indexOf(" ") == ss.length() - 2 || ss.indexOf(" ") == ss.length() - 1)
break;
getResult();
}

ss += " － ";
edit.setText(ss);
}
break;
case R.id.cheng: {
if (ss.length() == 0) {
break;
}
if (ss.contains(" ")) {
if (ss.indexOf(" ") == ss.length() - 3 || ss.indexOf(" ") == ss.length() - 2 || ss.indexOf(" ") == ss.length() - 1)
break;
getResult();
}

ss += " × ";
edit.setText(ss);
}
break;
case R.id.chu: {
if (ss.length() == 0) {
break;
}
if (ss.contains(" ")) {
if (ss.indexOf(" ") == ss.length() - 3 || ss.indexOf(" ") == ss.length() - 2 || ss.indexOf(" ") == ss.length() - 1)
break;
getResult();
}

ss += " / ";
edit.setText(ss);
}
break;
case R.id.sum:
getResult();
break;
}
}

private void getResult() {
double result = 0;
if (ss == null || ss.equals("")) return;
if (!ss.contains(" ")) return;
String s1 = ss.substring(0, ss.indexOf(" "));
String op = ss.substring(ss.indexOf(" ") + 1, ss.indexOf(" ") + 2);
String s2 = ss.substring(ss.indexOf(" ") + 3);
if (!s1.equals("") && !s2.equals("")) {
double d1 = Double.parseDouble(s1);
double d2 = Double.parseDouble(s2);
switch (op) {
case "＋":
result = d1 + d2;
break;
case "－":
result = d1 - d2;
break;
case "×":
result = d1 * d2;
break;
case "÷": {
if (d2 == 0) {
edit.setText("不能除以零");
break;
}
result = d1 / d2 * 1.0;
}
break;
}

int r = (int) result;
if (r == result) {
edit.setText("" + r);
ss = "" + r;
} else {
edit.setText(result + "");
ss = "" + result;
}

}

}
}

}