android 计算器

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1、核心：

（1）计算器的每一次输入要检查合法性

（2）计算的核心是把从文本编辑框获得的内容进行分离，将数字压入数字栈，符号进行优先级判断后压入符号栈，然后依次取出运算得到结果。

（3）计算流程图（由于电脑之前重装了，没有亿图，流程图不多就用写的了）

（4）重要代码

1、这个函数是对输入的运算式进行检查，如果输入的有错误，就进行提示，并且将输入框锁定。

（代码注释比较多，这里就不多说了）

private void TipChecker(String tipcommand1,String tipcommand2){

//Tipcode1表示数据类型，Tipcode2表示名词类型解释

int Tipcode1=0,Tipcode2=0;

//表示命令类型

int tiptype1=0,tiptype2=0;

//括号数

int bracket=0;

//+-*/^)根号不能作为第一位

if(tipcommand1.compareTo("#")==0&&(tipcommand2.compareTo("÷")==0||tipcommand2.compareTo("")==0||tipcommand2.compareTo("+")==0||tipcommand2.compareTo(")")==0||tipcommand2.compareTo("")==0||tipcommand2.compareTo("^")==0)){Tipcode1=-1;}

//定义存储字符串中最后一位的类型

elseif(tipcommand1.compareTo("#")!=0){if(tipcommand1.compareTo("(")==0){tiptype1=1;}elseif(tipcommand1.compareTo(")")==0){tiptype1=2;}else if(tipcommand1.compareTo(".")==0){tiptype1=3;}else if("0123456789".indexOf(tipcommand1)!=-1){tiptype1=4;}

else if("+-×÷".indexOf(tipcommand1)!=-1){tiptype1=5;}else if("√^".indexOf(tipcommand1)!=-1){tiptype1=6;}else if("sincostanlnlogn!".indexOf(tipcommand1)!=-1){tiptype1=7;}

//定义欲输入的按键类型

if(tipcommand2.compareTo("(")==0){tiptype2=1;}else if(tipcommand2.compareTo(")")==0){tiptype2=2;}else if(tipcommand2.compareTo(".")==0){tiptype2=3;}else if("0123456789".indexOf(tipcommand1)!=-1){tiptype2=4;}

else if("+-×÷".indexOf(tipcommand2)!=-1){tiptype2=5;}else if("√^".indexOf(tipcommand2)!=-1){tiptype2=6;}else if("sincostanlnlogn!".indexOf(tipcommand2)!=-1){tiptype2=7;}

switch(tiptype1){

case 1://左括号后面直接接右括号，“+*/”(符号不算)，或者“根号^”

if(tiptype2==2||(tiptype2==5&&tipcommand2.compareTo("-")!=0)||tiptype2==6) Tipcode1=1; break;

case 2://右括号后面接左括号、数字、“+-*/sin^...”

if(tiptype2==1||tiptype2==3||tiptype2==4||tiptype2==7) Tipcode1=2; break;

case 3://"."后面接左括号或者sincon...

if(tiptype2==1||tiptype2==7) Tipcode1=3;

//连续输入两个“.”

if(tiptype2==3) Tipcode1=8; break;

case 4://数字后面直接接左括号或者“sincon...”

if(tiptype2==1||tiptype2==7) Tipcode1=4;break;

case 5://+-×÷后面直接接右括号，+-×÷根号^

if(tiptype2==2||tiptype2==5||tiptype2==6) Tipcode1=5;break;

case 6://根号^后面直接接右括号，+-×÷根号^以及“sincos...”

if(tiptype2==2||tiptype2==5||tiptype2==6||tiptype2==7) Tipcode1=6;break;

case 7://sincos...后面直接接右括号“+-*/根号^”以及sincos

if(tiptype2==2||tiptype2==5||tiptype2==6||tiptype2==7) Tipcode1=7;break;

}

}//(tipcommand1.compareTo("#")!=0)

//检测小数点的重复性，Tipcondel=0，表明满足前面的规则

if(Tipcode1==0 &&tipcommand2.compareTo(".")==0){

int tip_point=0;

for(int i=0;i<tip_i;i++){

if(Tipcommand[i].compareTo(".")==0)

tip_point++;

//若出现以下几个运算符之一，小数点计数清零

if(Tipcommand[i].compareTo("sin")==0||Tipcommand[i].compareTo("cos")==0||Tipcommand[i].compareTo("tan")==0||

Tipcommand[i].compareTo("log")==0||Tipcommand[i].compareTo("ln")==0||Tipcommand[i].compareTo("n!")==0

||Tipcommand[i].compareTo("√")==0||Tipcommand[i].compareTo("^")==0||Tipcommand[i].compareTo("+")==0

||Tipcommand[i].compareTo("-")==0||Tipcommand[i].compareTo("×")==0||Tipcommand[i].compareTo("÷")==0

||Tipcommand[i].compareTo("(")==0||Tipcommand[i].compareTo(")")==0){tip_point=0;}

}

tip_point++;

//若小数点计数大于1，表明小数点重复了

if(tip_point>1){Tipcode1 = 8;}

}//if(Tipcode1==0 &&tipcommand2.compareTo(".")==0){}

//检测右括号是否匹配

if(Tipcode1==0 &&tipcommand2.compareTo(")")==0){

int tip_right_bracket=0;

for(int i=0;i<tip_i;i++){if(Tipcommand[i].compareTo("(")==0)tip_right_bracket++;if(Tipcommand[i].compareTo(")")==0)tip_right_bracket--;}

if(tip_right_bracket==0){Tipcode1=10;}

}

//检测输入=的合法性

if(Tipcode1==0 &&tipcommand2.compareTo("=")==0){

int tip_bracket=0;

for(int i=0;i<tip_i;i++){if(Tipcommand[i].compareTo("(")==0){tip_bracket++;}if(Tipcommand[i].compareTo(")")==0){tip_bracket--;}}

//若大于0，表明左括号还有未比配的

if(tip_bracket>0){Tipcode1=9;bracket=tip_bracket;}

//若前一个字符是以下之一，表明=不合法

else if(tip_bracket==0){if("√^sincostanlnlogn!".indexOf(tipcommand1)!=-1){Tipcode1=6;}

if("+-×÷".indexOf(tipcommand1)!=-1){Tipcode1=5;}}

}

//显示帮助和错误信息

TipShow(bracket,Tipcode1,Tipcode2,tipcommand1,tipcommand2);

}//private void TipChecker(String tipcommand1,String tipcommand2){}

2、计算部分的代码

public void process(String str) {

int weightPlus = 0, topOp = 0,

topNum = 0, flag = 1, weightTemp = 0;

//weightPlus为同一（）下的基本优先级，weightTemp临时记录优先级的变化

//topOp为weight[]，operator[]的计数器；topNum为number[]的计数器

//flag为正负数的计数器，1为正数，-1为负数

int weight[]; //保存operator栈中运算符的优先级，以topOp计数

double number[]; //保存数字，以topNum计数

char ch, ch_gai, operator[];//operator[]保存运算符，以topOp计数

String num;//记录数字，str以+-×÷()sctgl!√^分段，+-×÷()sctgl!√^字符之间的字符串即为数字

weight = new int[MAXLEN];

number = new double[MAXLEN];

operator = new char[MAXLEN];

String expression = str;

StringTokenizer expToken = new StringTokenizer(expression,"+-×÷()sctgl!√^");

int i = 0;

while (i < expression.length()) {

ch = expression.charAt(i);

//判断正负数

if (i == 0) {

if (ch == '-')

flag = -1;

} else if(expression.charAt(i-1) == '(' && ch == '-')

flag = -1;

//取得数字，并将正负符号转移给数字

if (ch <= '9' && ch >= '0'|| ch == '.' || ch == 'E') {

num = expToken.nextToken();

ch_gai = ch;

Log.e("guojs",ch+"--->"+i);

//取得整个数字

while (i < expression.length() &&

(ch_gai <= '9' && ch_gai >= '0'|| ch_gai == '.' || ch_gai == 'E'))

{

ch_gai = expression.charAt(i++);

Log.e("guojs","i的值为："+i);

}

//将指针退回之前的位置

if (i >= expression.length()) i-=1; else {i-=2;}

if (num.compareTo(".") == 0) number[topNum++] = 0;

//将正负符号转移给数字

else {

number[topNum++] = Double.parseDouble(num)*flag;

flag = 1;

}

//计算运算符的优先级

if (ch == '(') weightPlus+=4;

if (ch == ')') weightPlus-=4;

if (ch == '-' && flag == 1 || ch == '+' || ch == '×'|| ch == '÷' ||

ch == 's' ||ch == 'c' || ch == 't' || ch == 'g' || ch == 'l' ||

ch == '!' || ch == '√' || ch == '^') {

switch (ch) {

//+-的优先级最低，为1

case '+':

case '-':

weightTemp = 1 + weightPlus;

break;

//x÷的优先级稍高，为2

case '×':

case '÷':

weightTemp = 2 + weightPlus;

break;

//sincos之类优先级为3

case 's':

case 'c':

case 't':

case 'g':

case 'l':

case '!':

weightTemp = 3 + weightPlus;

break;

//其余优先级为4

//case '^':

//case '√':

default:

weightTemp = 4 + weightPlus;

break;

}

//如果当前优先级大于堆栈顶部元素，则直接入栈

if (topOp == 0 || weight[topOp-1] < weightTemp) {

weight[topOp] = weightTemp;

operator[topOp] = ch;

topOp++;

//否则将堆栈中运算符逐个取出，直到当前堆栈顶部运算符的优先级小于当前运算符

}else {

while (topOp > 0 && weight[topOp-1] >= weightTemp) {

switch (operator[topOp-1]) {

//取出数字数组的相应元素进行运算

case '+':

number[topNum-2]+=number[topNum-1];

break;

case '-':

number[topNum-2]-=number[topNum-1];

break;

case '×':

number[topNum-2]*=number[topNum-1];

break;

//判断除数为0的情况

case '÷':

if (number[topNum-1] == 0) {

showError(1,str_old);

return;

}

number[topNum-2]/=number[topNum-1];

break;

case '√':

if(number[topNum-1] == 0 || (number[topNum-2] < 0 &&

number[topNum-1] % 2 == 0)) {

showError(2,str_old);

return;

}

number[topNum-2] =

Math.pow(number[topNum-2], 1/number[topNum-1]);

break;

case '^':

number[topNum-2] =

Math.pow(number[topNum-2], number[topNum-1]);

break;

//计算时进行角度弧度的判断及转换

//sin

case 's':

if(drg_flag == true) {

number[topNum-1] = Math.sin((number[topNum-1]/180)*pi);

} else {

number[topNum-1] = Math.sin(number[topNum-1]);

}

topNum++;

break;

//cos

case 'c':

if(drg_flag == true) {

number[topNum-1] = Math.cos((number[topNum-1]/180)*pi);

} else {

number[topNum-1] = Math.cos(number[topNum-1]);

}

topNum++;

break;

//tan

case 't':

if(drg_flag == true) {

if((Math.abs(number[topNum-1])/90)%2 == 1) {

showError(2,str_old);

return;

}

number[topNum-1] = Math.tan((number[topNum-1]/180)*pi);

} else {

if((Math.abs(number[topNum-1])/(pi/2))%2 == 1) {

showError(2,str_old);

return;

}

number[topNum-1] = Math.tan(number[topNum-1]);

}

topNum++;

break;

//log

case 'g':

if(number[topNum-1] <= 0) {

showError(2,str_old);

return;

}

number[topNum-1] = Math.log10(number[topNum-1]);

topNum++;

break;

//ln

case 'l':

if(number[topNum-1] <= 0) {

showError(2,str_old);

return;

}

number[topNum-1] = Math.log(number[topNum-1]);

topNum++;

break;

//阶乘

case '!':

if(number[topNum-1] > 170) {

showError(3,str_old);

return;

} else if(number[topNum-1] < 0) {

showError(2,str_old);

return;

}

number[topNum-1] = N(number[topNum-1]);

topNum++;

break;

}

//继续取堆栈的下一个元素进行判断

topNum--;

topOp--;

}

//将运算符如堆栈

weight[topOp] = weightTemp;

operator[topOp] = ch;

topOp++;

}

i++;

}

//依次取出堆栈的运算符进行运算

while (topOp>0) {

//+-x直接将数组的后两位数取出运算

switch (operator[topOp-1]) {

case '+':

number[topNum-2]+=number[topNum-1];

break;

case '-':

number[topNum-2]-=number[topNum-1];

break;

case '×':

number[topNum-2]*=number[topNum-1];

break;

//涉及到除法时要考虑除数不能为零的情况

case '÷':

if (number[topNum-1] == 0) {

showError(1,str_old);

return;

}

number[topNum-2]/=number[topNum-1];

break;

case '√':

if(number[topNum-1] == 0 || (number[topNum-2] < 0 &&

number[topNum-1] % 2 == 0)) {

showError(2,str_old);

return;

}

number[topNum-2] =

Math.pow(number[topNum-2], 1/number[topNum-1]);

break;

case '^':

number[topNum-2] =

Math.pow(number[topNum-2], number[topNum-1]);

break;

//sin

case 's':

if(drg_flag == true) {

number[topNum-1] = Math.sin((number[topNum-1]/180)*pi);

} else {

number[topNum-1] = Math.sin(number[topNum-1]);

}

topNum++;

break;

//cos

case 'c':

if(drg_flag == true) {

number[topNum-1] = Math.cos((number[topNum-1]/180)*pi);

} else {

number[topNum-1] = Math.cos(number[topNum-1]);

}

topNum++;

break;

//tan

case 't':

if(drg_flag == true) {

if((Math.abs(number[topNum-1])/90)%2 == 1) {

showError(2,str_old);

return;

}

number[topNum-1] = Math.tan((number[topNum-1]/180)*pi);

} else {

if((Math.abs(number[topNum-1])/(pi/2))%2 == 1) {

showError(2,str_old);

return;

}

number[topNum-1] = Math.tan(number[topNum-1]);

}

topNum++;

break;

//对数log

case 'g':

if(number[topNum-1] <= 0) {

showError(2,str_old);

return;

}

number[topNum-1] = Math.log10(number[topNum-1]);

topNum++;

break;

//自然对数ln

case 'l':

if(number[topNum-1] <= 0) {

showError(2,str_old);

return;

}

number[topNum-1] = Math.log(number[topNum-1]);

topNum++;

break;

//阶乘

case '!':

if(number[topNum-1] > 170) {

showError(3,str_old);

return;

} else if(number[topNum-1] < 0) {

showError(2,str_old);

return;

}

number[topNum-1] = N(number[topNum-1]);

topNum++;

break;

}

//取堆栈下一个元素计算

topNum--;

topOp--;

}

//如果是数字太大，提示错误信息

if(number[0] > 7.3E306) {

showError(3,str_old);

return;

}

//输出最终结果

input.setText(String.valueOf(FP(number[0])));

tip.setText("计算完毕，要继续请按归零键 C");

mem.setText(str_old+"="+String.valueOf(FP(number[0])));

}

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