本文示例分享了实现简单计算器的具体代码，供大家参考。 具体内容如下
话不多说，先附上代码：
.java
package com.example.calculator;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import java.util.Stack;
public class MainActivity extends AppCompatActivity {
EditText edit = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
edit = findViewById(R.id.edit_textview);
}
public void btnClick(View view) {
switch (view.getId()){
case R.id.btn0:
edit.append("0");
break;
case R.id.btn1:
edit.append("1");
break;
case R.id.btn2:
edit.append("2");
break;
case R.id.btn3:
edit.append("3");
break;
case R.id.btn4:
edit.append("4");
break;
case R.id.btn5:
edit.append("5");
break;
case R.id.btn6:
edit.append("6");
break;
case R.id.btn7:
edit.append("7");
break;
case R.id.btn8:
edit.append("8");
break;
case R.id.btn9:
edit.append("9");
break;
case R.id.btnPlus:
edit.append("+");
break;
case R.id.btnSubtract:
edit.append("-");
break;
case R.id.btnMultiply:
edit.append("*");
break;
case R.id.btnDivide:
edit.append("/");
break;
}
}
public void btnEqual(View view) {
String str = edit.getText().toString();//1+2
String res="";
//Java计算代码
String result = calculate(str);
edit.setText(result);
}
private static int number(char[] arr,int start,int end){
StringBuilder buffer = new StringBuilder();
for(int i=start;i<=end;i++){
buffer.append(arr[i]);
}
return Integer.parseInt(buffer.toString());
}
// 待实现函数，在此函数中填入答题代码
private static int comp(String op){
if(op.equals("+") || op.equals("-"))
return 1;
if(op.equals("*") || op.equals("/"))
return 2;
return 0;
}
private static String compute(Integer a,Integer b,String op){
Integer res;
if(op.equals("+")) {
res = a + b;
return res.toString();
}
if (op.equals("-")) {
res= a - b;
return res.toString();
}
if (op.equals("*")) {
res = a * b;
return res.toString();
}
if (op.equals("/") && b!=0) {
res= a / b;
return res.toString();
}else{
return "error";
}
}
private static String calculate(String source) {
Stack numbers=new Stack<>();
Stack operator=new Stack<>();
operator.push(".");
char[] exps=source.toCharArray();
int start=0;
if(exps[0]=="-") numbers.push(0);
for(int j=0;j=comp(String.valueOf(exps[j]))){
Integer two=numbers.peek();numbers.pop();
Integer one=numbers.peek();numbers.pop();
String result=compute(one,two,operator.peek());operator.pop();
if (result.equals("error")) {
return result;
}
numbers.push(Integer.parseInt(result));
}
operator.push(String.valueOf(exps[j]));
}
}
numbers.push(number(exps,start,exps.length-1));
while (operator.size()>1){
Integer two=numbers.peek();numbers.pop();
Integer one =numbers.peek();numbers.pop();
String op=operator.peek();operator.pop();
String value = compute(one, two, op);
if (value.equals("error")) {
return value;
}
numbers.push(Integer.parseInt(value));
}
return numbers.peek().toString();
}
public void btnClear(View view) {
edit.setText("");
}
}
.xml
ntext=".MainActivity">
计算器界面：
