Android implements the calculator (and calculates the decimal point and parentheses)
- 2021-12-09 09:55:06
- OfStack
In this paper, we share the specific code of Android calculator for your reference, the specific contents are as follows
Layout code:
<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:stretchColumns="4"
android:focusable="true"
android:focusableInTouchMode="true"
tools:context=".MainActivity">
<TableRow
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#aaaaaa">
<LinearLayout
android:layout_width="0dp"
android:layout_height="200dp"
android:layout_column="0"
android:gravity="right"
android:layout_weight="1">
<EditText
android:id="@+id/content_box"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|right"
android:background="@null"
android:hint="0"
android:textSize="20pt" />
</LinearLayout>
</TableRow> <!-- Evaluate expression input box -->
<TableRow>
<Button
android:id="@+id/btn_c"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="0"
android:layout_weight="1"
android:text="C"
android:textColor="#ff0000"
android:textSize="12pt" />
<Button
android:id="@+id/btn_ce"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="1"
android:layout_weight="1"
android:text="CE"
android:textColor="#ff0000"
android:textSize="12pt" />
<Button
android:id="@+id/btn_aliquot"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="2"
android:layout_weight="1"
android:text="%"
android:textColor="#ff0000"
android:textSize="12pt" />
<Button
android:id="@+id/btn_divide"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="3"
android:layout_weight="1"
android:text="/"
android:textColor="#ff0000"
android:textSize="12pt" />
</TableRow>
<TableRow>
<Button
android:id="@+id/btn_leftBracket"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="0"
android:layout_span="1"
android:layout_weight="1"
android:text="("
android:textColor="#ff0000"
android:textSize="12pt" />
<Button
android:id="@+id/btn_rightBracket"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="0"
android:layout_span="1"
android:layout_weight="1"
android:text=")"
android:textColor="#ff0000"
android:textSize="12pt" />
</TableRow>
<TableRow>
<Button
android:id="@+id/btn_seven"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="0"
android:layout_weight="1"
android:text="7"
android:textSize="12pt" />
<Button
android:id="@+id/btn_eight"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="1"
android:layout_weight="1"
android:text="8"
android:textSize="12pt" />
<Button
android:id="@+id/btn_nine"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="2"
android:layout_weight="1"
android:text="9"
android:textSize="12pt" />
<Button
android:id="@+id/btn_multiply"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="3"
android:layout_weight="1"
android:text="*"
android:textColor="#ff0000"
android:textSize="12pt" />
</TableRow>
<TableRow>
<Button
android:id="@+id/btn_four"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="0"
android:layout_weight="1"
android:text="4"
android:textSize="12pt" />
<Button
android:id="@+id/btn_five"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="1"
android:layout_weight="1"
android:text="5"
android:textSize="12pt" />
<Button
android:id="@+id/btn_six"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="2"
android:layout_weight="1"
android:text="6"
android:textSize="12pt" />
<Button
android:id="@+id/btn_subtract"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="3"
android:layout_weight="1"
android:text="-"
android:textColor="#ff0000"
android:textSize="12pt" />
</TableRow>
<TableRow>
<Button
android:id="@+id/btn_one"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="0"
android:layout_weight="1"
android:text="1"
android:textSize="12pt" />
<Button
android:id="@+id/btn_two"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="1"
android:layout_weight="1"
android:text="2"
android:textSize="12pt" />
<Button
android:id="@+id/btn_three"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="2"
android:layout_weight="1"
android:text="3"
android:textSize="12pt" />
<Button
android:id="@+id/btn_add"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="3"
android:layout_weight="1"
android:text="+"
android:textColor="#ff0000"
android:textSize="12pt" />
</TableRow>
<TableRow>
<Button
android:id="@+id/btn_point"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="0"
android:layout_weight="1"
android:text="."
android:textSize="12pt" />
<Button
android:id="@+id/btn_zero"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="1"
android:layout_weight="1"
android:text="0"
android:textSize="12pt" />
<Button
android:id="@+id/btn_equal"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_column="2"
android:layout_weight="2"
android:text="="
android:textColor="#ff0000"
android:textSize="12pt" />
</TableRow>
</TableLayout>Activicy code:
package com.example.newcalculator;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import java.lang.reflect.Type;
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
/* Button definition */
Button btn_one; //1
Button btn_two; //2
Button btn_three; //3
Button btn_four; //4
Button btn_five; //5
Button btn_six; //6
Button btn_seven; //7
Button btn_eight; //8
Button btn_nine; //9
Button btn_zero; //0
Button btn_c; //c
Button btn_ce; //ce
Button btn_aliquot; //%
Button btn_divide; // Division sign
Button btn_multiply;//x
Button btn_subtract;//-
Button btn_add; //+
Button btn_point; //.
Button btn_equal; //=
Button btn_leftBracket;//(
Button btn_rightBracket;//)
EditText contentBox;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initControls();
initClickEvent();
}
// Find the control
private void initControls() {
btn_one = findViewById(R.id.btn_one);
btn_two = findViewById(R.id.btn_two);
btn_three = findViewById(R.id.btn_three);
btn_four = findViewById(R.id.btn_four);
btn_five = findViewById(R.id.btn_five);
btn_six = findViewById(R.id.btn_six);
btn_seven = findViewById(R.id.btn_seven);
btn_eight = findViewById(R.id.btn_eight);
btn_nine = findViewById(R.id.btn_nine);
btn_zero = findViewById(R.id.btn_zero);
btn_c = findViewById(R.id.btn_c);
btn_ce = findViewById(R.id.btn_ce);
btn_aliquot = findViewById(R.id.btn_aliquot);
btn_divide = findViewById(R.id.btn_divide);
btn_multiply = findViewById(R.id.btn_multiply);
btn_subtract = findViewById(R.id.btn_subtract);
btn_add = findViewById(R.id.btn_add);
btn_point = findViewById(R.id.btn_point);
btn_equal = findViewById(R.id.btn_equal);
contentBox = findViewById(R.id.content_box);
btn_leftBracket = findViewById(R.id.btn_leftBracket);
btn_rightBracket = findViewById(R.id.btn_rightBracket);
}
@Override
public void onClick(View view) {
switch (view.getId()){
case R.id.btn_one:{
changeVal("1");
}break;
case R.id.btn_two:{
changeVal("2");
}break;
case R.id.btn_three:{
changeVal("3");
}break;
case R.id.btn_four:{
changeVal("4");
}break;
case R.id.btn_five:{
changeVal("5");
}break;
case R.id.btn_six:{
changeVal("6");
}break;
case R.id.btn_seven:{
changeVal("7");
}break;
case R.id.btn_eight:{
changeVal("8");
}break;
case R.id.btn_nine:{
changeVal("9");
}break;
case R.id.btn_zero:{
changeVal("0");
}break;
case R.id.btn_aliquot:{
changeVal("%");
}break;
case R.id.btn_divide:{
changeVal("/");
}break;
case R.id.btn_multiply:{
changeVal("*");
}break;
case R.id.btn_subtract:{
changeVal("-");
}break;
case R.id.btn_add:{
changeVal("+");
}break;
case R.id.btn_rightBracket:{
changeVal(")");
}break;
case R.id.btn_leftBracket:{
changeVal("(");
}break;
case R.id.btn_c:{
funC();
}break;
case R.id.btn_ce:{
funClearAll();
}break;
case R.id.btn_point:{
changeVal(".");
}break;
case R.id.btn_equal:{
String str = contentBox.getText().toString();
Calculator calculator = new Calculator();
Double result = calculator.Eval(str);
contentBox.setText(result.toString());
}break;
}
}
private void changeVal(String flag){
String str = contentBox.getText().toString();
contentBox.setText(str+flag);
}
private void funC(){
String str = contentBox.getText().toString();
str = str.substring(0,str.length()-1);
contentBox.setText(str);
}
private void funClearAll(){
contentBox.setText("");
}
private void initClickEvent(){
btn_one.setOnClickListener(this);
btn_two.setOnClickListener(this);
btn_three.setOnClickListener(this);
btn_four.setOnClickListener(this);
btn_five.setOnClickListener(this);
btn_six.setOnClickListener(this);
btn_seven.setOnClickListener(this);
btn_eight.setOnClickListener(this);
btn_nine.setOnClickListener(this);
btn_zero.setOnClickListener(this);
btn_aliquot.setOnClickListener(this);
btn_divide.setOnClickListener(this);
btn_multiply.setOnClickListener(this);
btn_subtract.setOnClickListener(this);
btn_point.setOnClickListener(this);
btn_equal.setOnClickListener(this);
btn_add.setOnClickListener(this);
btn_c.setOnClickListener(this);
btn_ce.setOnClickListener(this);
btn_rightBracket.setOnClickListener(this);
btn_leftBracket.setOnClickListener(this);
}
}Evaluate expression code:
package com.example.newcalculator;
import java.util.*;
// Calculation 2*(4+(88-86)/2)
// Calculation 2*(4+(88-86)/2)
class Caculater {
private String[] sArry;// Save the segmented string
private Stack<String> houx = new Stack<String>();
private Stack<String> fuhao = new Stack<String>();
// Structure initialization
Caculater(String str) {
int i = str.length() - 1;
String temp = "";
int j = 0;
Boolean bool = true;
// Add to the left and right of the symbol 1 A # Character partition
while (true) {
if (!bool) break;
if (i == j) {
bool = false;
}
if (str.charAt(j) == '+'
|| str.charAt(j) == '-'
|| str.charAt(j) == '*'
|| str.charAt(j) == '/'
|| str.charAt(j) == '('
|| str.charAt(j) == ')') {
temp += '#';
temp += str.charAt(j);
temp += '#'; // After filling it out, it is 2#*##(#4#+##(#88#-#86#)##/#32#)#
} else {
temp += str.charAt(j);
}
j++;
}
sArry = temp.split("#+");// Split into strings with regular expressions, #+ Denote 1 One or more # Character // Results: [2,*,(,4,+,(,88,-,85,),/,2,)]
}
// Post-sequential arrangement
public void backsort() {
// Cycle sArry
for (int i = 0; i < sArry.length; i++) {
// If it is not a character, it will be directly push Into houx Stack
if (!sArry[i].equals("+")
&& !sArry[i].equals("-")
&& !sArry[i].equals("*")
&& !sArry[i].equals("/")
&& !sArry[i].equals("(")
&& !sArry[i].equals(")")) {
houx.push(sArry[i]);
continue;
// Otherwise, it is a character. If the symbol stack is empty, it will be directly put into the stack
} else if (fuhao.isEmpty()) {
fuhao.push(sArry[i]);
continue;
// If it is (parentheses, go directly to the symbol stack
} else if (sArry[i].equals("(")) {
fuhao.push(sArry[i]);
continue;
// If) parentheses
} else if (sArry[i].equals(")")) {
/**
* Keep going out of the stack until (parentheses appear)
*
*/
while (!fuhao.peek().equals("(")) {
houx.push(fuhao.pop());
}
fuhao.pop();// Clear (brackets)
// If it is not empty and the symbol to be entered has higher priority than the symbol at the top of the symbol stack, the push Into symbol stack
} else if (!fuhao.isEmpty() && check(sArry[i], fuhao.peek())) { //
fuhao.push(sArry[i]);
continue;
// Otherwise, the symbol with high priority in the symbol stack is removed from the stack, push Into houx Stack, and then store the symbols into the symbol stack
} else {
houx.push(fuhao.pop());
fuhao.push(sArry[i]);
continue;
}
}
// After traversing, the symbols in the stack are directly out of the stack in turn. push Into houx Stack
while (!fuhao.isEmpty()) {
houx.push(fuhao.pop());
}// The result is: 2 4 88 86 - 2 / + * In-stack sequence
}
//check Contrast priority
private boolean check(String a, String b) {
// If the symbol stack is (parentheses, return directly true
if (b.equals("(")) {
return true;
}
// If the priority in the symbol stack is higher than the one to be entered, return false
if ((b.equals("*") || b.equals("/")) && (a.equals("+") || a.equals("-"))) { //b>a
return false;
}
// . . . . . . . . . . . . . Returns the low of true
if ((b.equals("+") || b.equals("-")) && (a.equals("*") || a.equals("/"))) { //b<a
return true;
}
return false;
}
// Off-stack calculation
public Double suan() {
backsort();// Post-sequential arrangement
// Result stack end
Stack<Double> end = new Stack<Double>();
// Traversal houx Stack
for (int i = 0; i < houx.size(); i++) {
// If it's a plus sign, end pop Two numbers come out, and the calculated results are put into the stack
if (houx.get(i).equals("+")) {
Double b = end.pop();
Double a = end.pop();
end.push(a + b);
continue;
// If it's a minus sign, end pop Two numbers are stacked, and the calculated results are put into the stack
} else if (houx.get(i).equals("-")) {
Double b = end.pop();
Double a = end.pop();
end.push(a - b);
continue;
// If it's a multiplication sign, end pop Two numbers are stacked, and the calculated results are put into the stack
} else if (houx.get(i).equals("*")) {
Double b = end.pop();
Double a = end.pop();
end.push(a * b);
continue;
// If it is a division sign, end pop Two numbers are stacked, and the calculated results are put into the stack
} else if (houx.get(i).equals("/")) {
Double b = end.pop();
Double a = end.pop();
end.push(a / b);
continue;
} else if (houx.get(i).isEmpty()) {
continue;
} else {
// It's not a symbol, that is, a number, Integer.parseInt Turn int Type, push Stack
end.push(Double.parseDouble(houx.get(i)));
}
}
// Output result
return end.pop();
}
}
public class Calculator {
static String str="";
public Double Eval(String str){
// Structured
Caculater cl = new Caculater(str);
// Calculation
Double result = cl.suan();
return result;
}
}Please check "Calculator Special Topics" for wonderful articles about calculators, and more wonderful articles are waiting for you to discover!