中间有负数运算的时候有些bug, 时间紧迫，算法问题有待后期完善，
package com.lw.calc;
import java.math.BigDecimal;
import java.math.RoundingMode;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
/***
* 我的计算器
* @author david.li
* @version 1.0
* create date : 20140905
*/
public class CALCActivity extends Activity {
private static final String NUM_0 = "0";
private static final String NUM_MAX = "∞";
private static final String NUM_MIN = "-∞";
private EditText text;
private EditText calc_text;
private Button btn_no0;
private Button btn_no1;
private Button btn_no2;
private Button btn_no3;
private Button btn_no4;
private Button btn_no5;
private Button btn_no6;
private Button btn_no7;
private Button btn_no8;
private Button btn_no9;
private Button btn_add;
private Button btn_sub;
private Button btn_mul;
private Button btn_div;
private Button btn_pot;
private Button btn_clr;
private Button btn_del;
private Button btn_equ;
private OnClickListener listener_no0;
private OnClickListener listener_no1;
private OnClickListener listener_no2;
private OnClickListener listener_no3;
private OnClickListener listener_no4;
private OnClickListener listener_no5;
private OnClickListener listener_no6;
private OnClickListener listener_no7;
private OnClickListener listener_no8;
private OnClickListener listener_no9;
private OnClickListener listener_btn_add;
private OnClickListener listener_btn_sub;
private OnClickListener listener_btn_mul;
private OnClickListener listener_btn_div;
private OnClickListener listener_btn_pot;
private OnClickListener listener_btn_clr;
private OnClickListener listener_btn_del;
private OnClickListener listener_btn_equ;
public enum CALC_TYPE {
ADD("add", 1),
SUB("sub", 2),
MUL("mul", 3),
DIV("div", 4);
private String name;
private int value;
private CALC_TYPE(String name, int value) {
this.name = name;
this.value = value;
}
@Override
public String toString() {
return this.name;
}
}
/***
* 创建打开我的计算器窗体
* 1、获取窗口控件
* 2、实现每一个控件的点击事件监听（处理操作过程）
* 3、将事件监听附加到对应的窗体控件上
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
setTitle("David 计算器");
/***
* 获取每一个窗体控件
*/
text = (EditText)findViewById(R.id.text);
text.setText(NUM_0);
calc_text = (EditText)findViewById(R.id.calc_text);
btn_no0 = (Button)findViewById(R.id.btn_no0);
btn_no1 = (Button)findViewById(R.id.btn_no1);
btn_no2 = (Button)findViewById(R.id.btn_no2);
btn_no3 = (Button)findViewById(R.id.btn_no3);
btn_no4 = (Button)findViewById(R.id.btn_no4);
btn_no5 = (Button)findViewById(R.id.btn_no5);
btn_no6 = (Button)findViewById(R.id.btn_no6);
btn_no7 = (Button)findViewById(R.id.btn_no7);
btn_no8 = (Button)findViewById(R.id.btn_no8);
btn_no9 = (Button)findViewById(R.id.btn_no9);
btn_add = (Button)findViewById(R.id.btn_add);
btn_sub = (Button)findViewById(R.id.btn_sub);
btn_mul = (Button)findViewById(R.id.btn_mul);
btn_div = (Button)findViewById(R.id.btn_div);
btn_pot = (Button)findViewById(R.id.btn_pot);
btn_clr = (Button)findViewById(R.id.btn_clr);
btn_del = (Button)findViewById(R.id.btn_del);
btn_equ = (Button)findViewById(R.id.btn_equ);
/***
* 实现每一个控件的点击事件监听（处理操作过程）
*/
listener_no0 = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(reInput(num_now)) {
num_now = NUM_0;
} else {
num_now += NUM_0;
}
text.setText(num_now);
}
};
listener_no1 = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(reInput(num_now)) {
num_now = "1";
} else {
num_now += "1";
}
text.setText(num_now);
}
};
listener_no2 = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(reInput(num_now)) {
num_now = "2";
} else {
num_now += "2";
}
text.setText(num_now);
}
};
listener_no3 = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(reInput(num_now)) {
num_now = "3";
} else {
num_now += "3";
}
text.setText(num_now);
}
};
listener_no4 = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(reInput(num_now)) {
num_now = "4";
} else {
num_now += "4";
}
text.setText(num_now);
}
};
listener_no5 = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(reInput(num_now)) {
num_now = "5";
} else {
num_now += "5";
}
text.setText(num_now);
}
};
listener_no6 = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(reInput(num_now)) {
num_now = "6";
} else {
num_now += "6";
}
text.setText(num_now);
}
};
listener_no7 = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(reInput(num_now)) {
num_now = "7";
} else {
num_now += "7";
}
text.setText(num_now);
}
};
listener_no8 = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(reInput(num_now)) {
num_now = "8";
} else {
num_now += "8";
}
text.setText(num_now);
}
};
listener_no9 = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(reInput(num_now)) {
num_now = "9";
} else {
num_now += "9";
}
text.setText(num_now);
}
};
listener_btn_pot = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(num_now.indexOf(".") == -1) {
num_now += ".";
}
text.setText(num_now);
}
};
listener_btn_add = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(num_now.endsWith("+")
|| num_now.endsWith("-")
|| num_now.endsWith("x")
|| num_now.endsWith("÷")) {
num_now = num_now.substring(0, num_now.length() - 1);
}
text.setText(num_now + "+");
}
};
listener_btn_sub = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(num_now.endsWith("+")
|| num_now.endsWith("-")
|| num_now.endsWith("x")
|| num_now.endsWith("÷")) {
num_now = num_now.substring(0, num_now.length() - 1);
}
text.setText(num_now + "-");
}
};
listener_btn_mul = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(num_now.endsWith("+")
|| num_now.endsWith("-")
|| num_now.endsWith("x")
|| num_now.endsWith("÷")) {
num_now = num_now.substring(0, num_now.length() - 1);
}
text.setText(num_now + "x");
}
};
listener_btn_div = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(num_now.endsWith("+")
|| num_now.endsWith("-")
|| num_now.endsWith("x")
|| num_now.endsWith("÷")) {
num_now = num_now.substring(0, num_now.length() - 1);
}
text.setText(num_now + "÷");
}
};
listener_btn_clr = new OnClickListener() {
public void onClick(View v) {
text.setText(NUM_0);
calc_text.setText("");
}
};
listener_btn_del = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(!NUM_0.equals(num_now)) {
if(num_now.length() > 1) {
num_now = num_now.substring(0, num_now.length() - 1);
} else {
num_now = NUM_0;
}
}
text.setText(num_now);
if(NUM_0.equals(num_now)) {
calc_text.setText("");
}
}
};
listener_btn_equ = new OnClickListener() {
public void onClick(View v) {
String num_now = text.getText().toString();
if(num_now.endsWith("+")
|| num_now.endsWith("-")
|| num_now.endsWith("x")
|| num_now.endsWith("÷")) {
num_now = num_now.substring(0, num_now.length() - 1);
}
try {
String num = calc(num_now);
text.setText(num);
calc_text.setText(num_now + "=");
} catch (Exception e) {
}
}
};
/***
* 给数字按钮、运算操作添加点击事件监听
*/
// 数字按钮监听
btn_no0.setOnClickListener(listener_no0);
btn_no1.setOnClickListener(listener_no1);
btn_no2.setOnClickListener(listener_no2);
btn_no3.setOnClickListener(listener_no3);
btn_no4.setOnClickListener(listener_no4);
btn_no5.setOnClickListener(listener_no5);
btn_no6.setOnClickListener(listener_no6);
btn_no7.setOnClickListener(listener_no7);
btn_no8.setOnClickListener(listener_no8);
btn_no9.setOnClickListener(listener_no9);
// 运算操作按钮监听
btn_pot.setOnClickListener(listener_btn_pot);
btn_add.setOnClickListener(listener_btn_add);
btn_sub.setOnClickListener(listener_btn_sub);
btn_mul.setOnClickListener(listener_btn_mul);
btn_div.setOnClickListener(listener_btn_div);
btn_clr.setOnClickListener(listener_btn_clr);
btn_del.setOnClickListener(listener_btn_del);
btn_equ.setOnClickListener(listener_btn_equ);
}
private String calc(String num) {
if(num.indexOf(NUM_MAX) > -1) {
return NUM_MAX;
}
if(num.indexOf(NUM_MIN) > -1) {
return NUM_MIN;
}
boolean div_zero = false; // n÷0
boolean zero_div = false; // 0÷n
String[] array_add = num.split("\\+");
BigDecimal bd = BigDecimal.ZERO;
for(int i=0; i<array_add.length; i++) {
if(array_add[i].indexOf("-") > -1
||array_add[i].indexOf("x") > -1
||array_add[i].indexOf("÷") > -1) {
String[] array_sub = array_add[i].split("\\-");
for(int j=0; j<array_sub.length; j++) {
if(array_sub[j].indexOf("x") > -1
||array_sub[j].indexOf("÷") > -1) {
String[] array_div = array_sub[j].split("\\÷");
BigDecimal sum_mul = BigDecimal.ONE;
BigDecimal sum_div = BigDecimal.ONE;
for(int k=0; k<array_div.length; k++) {
if(array_div[k].indexOf("x") > -1) {
String[] array_mul = array_div[k].split("x");
for(int h=0; h<array_mul.length; h++) {
if(k!=0 && h==0) {
if(sum_mul.compareTo(BigDecimal.ZERO) == 0) {
zero_div = true;
}
if("0".equals(array_mul[h])) {
div_zero = true;
sum_mul = sum_mul.divide(BigDecimal.ONE); // 用于计算结果的正负
} else {
sum_mul = sum_mul.divide(new BigDecimal(array_mul[h]), 10, RoundingMode.HALF_UP);
}
} else {
sum_mul = sum_mul.multiply(new BigDecimal(array_mul[h]));
}
}
} else {
if(k==0) {
sum_div = sum_div.multiply(new BigDecimal(array_div[k]));
} else {
if(sum_div.compareTo(BigDecimal.ZERO) == 0) {
zero_div = true;
}
if(NUM_0.equals(array_div[k])) {
div_zero = true;
sum_div = sum_div.divide(BigDecimal.ONE); // 用于计算结果的正负
} else {
sum_div = sum_div.divide(new BigDecimal(array_div[k]), 10, RoundingMode.HALF_UP);
}
}
}
}
if(j==0) {
bd = bd.add(sum_mul.multiply(sum_div));
} else {
bd = bd.subtract(sum_mul.multiply(sum_div));
}
} else {
if(j==0) {
if("".equals(array_sub[j]) == false) {
bd = bd.add(new BigDecimal(array_sub[j]));
}
} else {
bd = bd.subtract(new BigDecimal(array_sub[j]));
}
}
}
} else {
bd = bd.add(new BigDecimal(array_add[i]));
}
}
String result = bd.toString();
if(result.indexOf(".") > -1) {
String[] ns = result.split("\\.");
if(new BigDecimal(ns[1]).equals(BigDecimal.ZERO)) {
result = ns[0];
} else {
String end = ns[1];
int len = end.length();
for(int i=0; i<len; i++) {
if(end.endsWith("0")) {
end = end.substring(0, end.length() - 1);
}
}
result = ns[0] + "." + end;
}
}
if(div_zero && bd.compareTo(BigDecimal.ZERO) >= 0) {
result = NUM_MAX;
} else if(div_zero && bd.compareTo(BigDecimal.ZERO) < 0) {
result = NUM_MIN;
}
if(zero_div) {
result = NUM_0;
}
if(zero_div && div_zero) {
result = "NAN";
}
return result;
}
private boolean reInput(String num_now) {
if(NUM_0.equals(num_now) || NUM_MAX.equals(num_now) || NUM_MIN.equals(num_now)) {
return true;
}
return false;
}
}
源码查看附件：