Android studio 简易计算器App的实现及实现加减乘除功能（附完整源码）
在Android studio 实现简易计算器App并实现加减乘除功能
结果
activity_main.xml
MainActivity.java
package com.example.a86189.szcounter;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends AppCompatActivity {
Button btn1; // 数字1
Button btn2; // 数字2
Button btn3; // 数字3
Button btn4; // 数字4
Button btn5; // 数字5
Button btn6; // 数字6
Button btn7; // 数字7
Button btn8; // 数字8
Button btn9; // 数字9
Button btn0; // 数字0
Button add; // +号
Button sub; // -号
Button mul; // *号
Button div; // 除号
Button dot; // 小数点
Button equ; // =号
Button clear; //清除
EditText result; // 显示文本
double num1 = 0, num2 = 0; //计算的数字
double Result = 0;//计算结果
int op = 0;//判断操作符
String opd = " ";//显示操作符
@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.btn_1);
btn2 = (Button)findViewById(R.id.btn_2);
btn3 = (Button)findViewById(R.id.btn_3);
btn4 = (Button)findViewById(R.id.btn_4);
btn5 = (Button)findViewById(R.id.btn_5);
btn6 = (Button)findViewById(R.id.btn_6);
btn7 = (Button)findViewById(R.id.btn_7);
btn8 = (Button)findViewById(R.id.btn_8);
btn9 = (Button)findViewById(R.id.btn_9);
btn0 = (Button)findViewById(R.id.btn_0);
add = (Button)findViewById(R.id.btn_add);
sub = (Button)findViewById(R.id.btn_sub);
mul = (Button)findViewById(R.id.btn_mul);
div = (Button)findViewById(R.id.btn_div);
equ = (Button)findViewById(R.id.btn_equ);
dot = (Button)findViewById(R.id.btn_dot);
clear =(Button) findViewById(R.id.btn_clear);
result =(EditText) findViewById(R.id.et_result);
// 按钮的单击事件
btn1.setOnClickListener(new Click());
btn2.setOnClickListener(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());
add.setOnClickListener(new Click());
sub.setOnClickListener(new Click());
mul.setOnClickListener(new Click());
div.setOnClickListener(new Click());
equ.setOnClickListener(new Click());
dot.setOnClickListener(new Click());
clear.setOnClickListener(new Click());
result.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.btn_0: //获取，0-9、小数点，并在编辑框显示
String myString = result.getText().toString();
myString += "0";
result.setText(myString);
break;
case R.id.btn_1:
String myString1 = result.getText().toString();
myString1 += "1";
result.setText(myString1);
break;
case R.id.btn_2:
String myString2 = result.getText().toString();
myString2 += "2";
result.setText(myString2);
break;
case R.id.btn_3:
String myString3 = result.getText().toString();
myString3 += "3";
result.setText(myString3);
break;
case R.id.btn_4:
String myString4 = result.getText().toString();
myString4 += "4";
result.setText(myString4);
break;
case R.id.btn_5:
String myString5 = result.getText().toString();
myString5 += "5";
result.setText(myString5);
break;
case R.id.btn_6:
String myString6 = result.getText().toString();
myString6 += "6";
result.setText(myString6);
break;
case R.id.btn_7:
String myString7 = result.getText().toString();
myString7 += "7";
result.setText(myString7);
break;
case R.id.btn_8:
String myString8 = result.getText().toString();
myString8 += "8";
result.setText(myString8);
break;
case R.id.btn_9:
String myString9 = result.getText().toString();
myString9 += "9";
result.setText(myString9);
break;
case R.id.btn_dot:
String myStringDot = result.getText().toString();
myStringDot += ".";
result.setText(myStringDot);
break;
case R.id.btn_add: //判断，使用加减乘除的操作符
String myStringAdd = result.getText().toString();
if (myStringAdd.equals(null)) {
return;
}
num1 = Double.valueOf(myStringAdd);
result.setText(null);
op = 1;
opd = "+";
break;
case R.id.btn_sub:
String myStringSub = result.getText().toString();
if (myStringSub.equals(null)) {
return;
}
num1 = Double.valueOf(myStringSub);
result.setText(null);
op = 2;
opd = "-";
break;
case R.id.btn_mul:
String myStringMul = result.getText().toString();
if (myStringMul.equals(null)) {
return;
}
num1 = Double.valueOf(myStringMul);
result.setText(null);
op = 3;
opd = "×";
break;
case R.id.btn_div:
String myStringDiv = result.getText().toString();
if (myStringDiv.equals(null)) {
return;
}
num1 = Double.valueOf(myStringDiv);
result.setText(null);
op = 4;
opd = "÷";
break;
case R.id.btn_clear: //清除，将编辑框文本显示为空
result.setText(null);
break;
case R.id.btn_equ: //计算，以操作符为判断，选择所需的运算，并将结果输出
String myStringEqu = result.getText().toString();
if (myStringEqu.equals(null)) {
return;
}
num2 = Double.valueOf(myStringEqu);
result.setText(null);
switch (op) {
case 0:
Result = num2;
break;
case 1:
Result = num1 + num2;
break;
case 2:
Result = num1 - num2;
break;
case 3:
Result = num1 * num2;
break;
case 4:
if (num2 == 0) //除法中分子与分母之分
Result = 0;
else
Result = num1 / num2;
break;
default:
Result = 0;
break;
}
result.setText(Double.toString(num1) + opd + Double.toString(num2) + "=" + Double.toString(Result)); //将结果完整输出
break;
default:
break;
}
}
}
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