私はアンドロイドで電卓を設計しています。たとえば、5+5 を実行してから = を押すと、10 になります。ただし、5+5+5 を実行してから = を押すと、10 になります。たとえば、5+5+5 の場合、等号をヒットすると 15 になります。これが私がこれまでに持っているものです：
package edu.uwstout.pocketcalculator;
import java.text.DecimalFormat;
import java.util.ArrayList;
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.graphics.Color;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class Basic extends Activity {
private Button one, two, three, four,
five, six, seven, eight, nine, zero,
add, subtract, multiply, divide, decimal,
negative, enter, clear;
private TextView output;
double numberOne;
double numberTwo;
double total;
double plusMinus;
int plus;
int minus;
int multiply_counter;
int divide_counter;
int decimal_counter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_basic);
one = (Button) findViewById(R.id.b1);
one.setTextColor(Color.BLACK);
one.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
output.setText(output.getText() + "1");
}
});
two = (Button) findViewById(R.id.b2);
two.setTextColor(Color.BLACK);
two.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
output.setText(output.getText() + "2");
}
});
three = (Button) findViewById(R.id.b3);
three.setTextColor(Color.BLACK);
three.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
output.setText(output.getText() + "3");
}
});
four = (Button) findViewById(R.id.b4);
four.setTextColor(Color.BLACK);
four.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
output.setText(output.getText() + "4");
}
});
five = (Button) findViewById(R.id.b5);
five.setTextColor(Color.BLACK);
five.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
output.setText(output.getText() + "5");
}
});
six = (Button) findViewById(R.id.b6);
six.setTextColor(Color.BLACK);
six.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
output.setText(output.getText() + "6");
}
});
seven = (Button) findViewById(R.id.b7);
seven.setTextColor(Color.BLACK);
seven.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
output.setText(output.getText() + "7");
}
});
eight = (Button) findViewById(R.id.b8);
eight.setTextColor(Color.BLACK);
eight.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
output.setText(output.getText() + "8");
}
});
nine = (Button) findViewById(R.id.b9);
nine.setTextColor(Color.BLACK);
nine.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
output.setText(output.getText() + "9");
}
});
zero = (Button) findViewById(R.id.b0);
zero.setTextColor(Color.BLACK);
zero.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
output.setText(output.getText() + "9");
}
});
decimal = (Button) findViewById(R.id.bDot);
decimal.setTextColor(Color.BLACK);
decimal.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
if(decimal_counter == 0){
output.setText(output.getText() + ".");
}
decimal_counter = 1;
}
});
negative = (Button) findViewById(R.id.bNeg);
negative.setTextColor(Color.BLACK);
negative.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
plusMinus=(Double.parseDouble(String.valueOf(output.getText())));
plusMinus=plusMinus*(-1);
output.setText(String.valueOf(plusMinus));
}
});
add = (Button) findViewById(R.id.bPlus);
add.setTextColor(Color.BLACK);
add.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
numberOne=(Double.parseDouble(String.valueOf(output.getText())));
plus = 1;
output.setText("");
decimal_counter=0;
}
});
subtract = (Button) findViewById(R.id.bMinus);
subtract.setTextColor(Color.BLACK);
subtract.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
numberOne=(Double.parseDouble(String.valueOf(output.getText())));
output.setText("");
minus=1;
decimal_counter=0;
}
});
multiply = (Button) findViewById(R.id.bTimes);
multiply.setTextColor(Color.BLACK);
multiply.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
numberOne=(Double.parseDouble(String.valueOf(output.getText())));
output.setText("");
multiply_counter=1;
decimal_counter=0;
}
});
divide = (Button) findViewById(R.id.bDivide);
divide.setTextColor(Color.BLACK);
divide.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
numberOne=(Double.parseDouble(String.valueOf(output.getText())));
output.setText("");
divide_counter=1;
decimal_counter=0;
}
});
enter = (Button) findViewById(R.id.bEnter);
enter.setTextColor(Color.BLACK);
enter.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
output.setText(String.valueOf(enter(numberOne)));
}
});
clear = (Button) findViewById(R.id.bClear);
clear.setTextColor(Color.BLACK);
clear.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
output.setText("");
decimal_counter=0;
}
});
output = (TextView) findViewById(R.id.bOutput);
registerForContextMenu(output);
}
public double enter(double numberOne){
numberTwo = (Double.parseDouble(String.valueOf(output.getText())));
if(plus>0){
total = numberOne + numberTwo;
numberOne = 0;
numberTwo = 0;
plus = 0;
return total;
}
if(minus>0){
total = numberOne - numberTwo;
numberOne = 0;
numberTwo = 0;
minus = 0;
return total;
}
if(multiply_counter>0){
total = numberOne * numberTwo;
numberOne = 0;
numberTwo = 0;
multiply_counter = 0;
return total;
}
if(divide_counter>0){
total = numberOne / numberTwo;
numberOne = 0;
numberTwo = 0;
divide_counter = 0;
return total;
}
return total;
}
}