I have built a simple calculator and i am trying to get it to multiply and subtract correctly as i already have addition and division working. my problem is i cant figure out why multiplication and subtraction wouldn't be working.Here is what i have.
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.stage.*;
import javafx.scene.*;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.HBox;
public class JavaFxCalc extends Application implements
EventHandler<ActionEvent>{
Button [] numButtons;
Insets insets = new Insets(5,5,5,5);
TextField resultsTextField;
HBox topRow,middleRow,lowerRow,bottomRow;
Scene mainScene;
String[] template = {"7","8","9","/",
"4","5","6","*",
"1","2","3","-",
"0",".","=","+",
};
int num1;
String currentOperation;
@Override
public void handle(ActionEvent e){
//numbers 7-9
for(int x =0; x<3; x++){
if(e.getSource() == numButtons[x]){
String numOne = resultsTextField.getText();
resultsTextField.setText(numOne+template[x]);
}
}
//numbers 4-6
for(int x =4; x<7; x++){
if(e.getSource() == numButtons[x]){
String numOne = resultsTextField.getText();
resultsTextField.setText(numOne+template[x]);
}
}
//numbers 1-3
for(int x =7; x<11; x++){
if(e.getSource() == numButtons[x]){
String numOne = resultsTextField.getText();
resultsTextField.setText(numOne+template[x]);
}
}
// 0 and a decimal
for(int x =11; x<14; x++){
if(e.getSource() == numButtons[x]){
String numOne = resultsTextField.getText();
resultsTextField.setText(numOne+template[x]);
}
}
// operation
for(int x =0; x<16; x++) {
if(e.getSource() == numButtons[7] || e.getSource() == numButtons[3] ||
e.getSource() == numButtons[11] || e.getSource() == numButtons[15]){
String firstNum = resultsTextField.getText();
num1 = Integer.parseInt(firstNum);
resultsTextField.setText("");
currentOperation = ((Button) e.getSource()).getText();
}
}
// Equals sign
for(int x =14; x<=15; x++){
if(e.getSource() == numButtons[x]){
String secondNum = resultsTextField.getText();
Integer num2 = Integer.parseInt(secondNum);
switch (currentOperation) {
case "+":
num1 = num1 + num2;
resultsTextField.setText(String.valueOf(num1));
break;
case "-":
num1 = num1 - num2;
resultsTextField.setText(String.valueOf(num1));
break;
case "*":
num1 = num1 * num2;
resultsTextField.setText(String.valueOf(num1));
break;
case "/":
num1 = num1 / num2;
resultsTextField.setText(String.valueOf(num1));
break;
default:
break;
}
}
}
}
@Override
public void start(Stage primaryStage)throws Exception{
primaryStage.setTitle("Javafx Calc");
primaryStage.setResizable(false);
primaryStage.sizeToScene();
GridPane mainPane = new GridPane();
mainScene = new Scene(mainPane);
resultsTextField = new TextField();
resultsTextField.setPrefSize(100, 50);
mainPane.setPadding(insets);
mainPane.setConstraints(resultsTextField,0,0);
//adds buttons 7-9 and division sign to top row and adds top row to
mainPane
topRow = new HBox(5);
topRow.setAlignment(Pos.CENTER);
topRow.setPadding(insets);
numButtons = new Button[17];
for(int x=0; x < 4; x++){
numButtons[x] = new Button();
numButtons[x].setText(template[x]);
topRow.getChildren().addAll(numButtons[x]);
}
mainPane.setConstraints(topRow,0,1);
//adds buttons 4-6 and multiplication sign to middle row and adds middle
row to mainPane
middleRow = new HBox(5);
middleRow.setAlignment(Pos.CENTER);
middleRow.setPadding(insets);
for(int x=4; x < 8; x++){
numButtons[x] = new Button();
numButtons[x].setText(template[x]);
middleRow.getChildren().addAll(numButtons[x]);
}
mainPane.setConstraints(middleRow,0,2);
//adds 1-3 and adds minus sign to lowerRow and adds lower row to mainPane
lowerRow = new HBox(5);
lowerRow.setAlignment(Pos.CENTER);
lowerRow.setPadding(insets);
for(int x=8; x < 12; x++){
numButtons[x] = new Button();
numButtons[x].setText(template[x]);
lowerRow.getChildren().addAll(numButtons[x]);
}
mainPane.setConstraints(lowerRow,0,3);
//adds 0, . , = and + to the bottom row and adds the bottom row to the
mainPane
bottomRow = new HBox(5);
bottomRow.setAlignment(Pos.CENTER);
bottomRow.setPadding(insets);
for(int x=12; x < 16; x++){
numButtons[x] = new Button();
numButtons[x].setText(template[x]);
bottomRow.getChildren().addAll(numButtons[x]);
}
mainPane.setConstraints(bottomRow,0,4);
//sets preffered size for all buttons and adds action listeners to each
button
for(int x =0; x < 16; x++){
numButtons[x].setPrefSize(50,30);
numButtons[x].setOnAction(this);
}
mainPane.getChildren().addAll(resultsTextField,topRow
,middleRow,lowerRow,bottomRow);
primaryStage.setScene(mainScene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
The main issue with your code comes from that you're handling everything in a one big event handler.
The for loops causes multiple actions to be carried out for a single event, causing multiple issues for you.
You should restructure it so that you add a separate event handler for each specific task so that each handler can do it's specific thing without filtering out everything that it shouldn't do - this is a lot easier to keep track of.
public class JavaFxCalc extends Application {
// All members are the same as your original code
// public void handle(ActionEvent e) has been removed
@Override
public void start(Stage primaryStage) throws Exception {
// All setup code is the same up until the for-loop below
//sets preffered size for all buttons
for (int x = 0; x < 16; x++) {
numButtons[x].setPrefSize(50, 30);
}
// Add action handlers for the number buttons
for (int x = 0; x < 14; x++) {
// We need a final variable for the event handler
final int index = x;
if(x == 3 || x == 7 || x == 11) {
// Skip the operation buttons, we won't hit 15 (+) here since the loop only goes to 13 (.)
continue;
}
// This will create one unique event handler for each button.
// Since we have the final index variable here we don't need to
// iterate over the buttons to find the correct template position - we already know it
numButtons[x].setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(final ActionEvent event) {
String numOne = resultsTextField.getText();
resultsTextField.setText(numOne + template[index]);
}
});
}
// Add action handlers for the operation buttons
for (int x : new int[]{3, 7, 11, 15}) {
numButtons[x].setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(final ActionEvent event) {
String firstNum = resultsTextField.getText();
num1 = Integer.parseInt(firstNum);
resultsTextField.setText("");
currentOperation = ((Button) event.getSource()).getText();
}
});
}
// Add action handler for the equals button
numButtons[14].setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(final ActionEvent event) {
String secondNum = resultsTextField.getText();
int num2 = Integer.parseInt(secondNum);
switch (currentOperation) {
case "+":
num1 = num1 + num2;
resultsTextField.setText(String.valueOf(num1));
break;
case "-":
num1 = num1 - num2;
resultsTextField.setText(String.valueOf(num1));
break;
case "*":
num1 = num1 * num2;
resultsTextField.setText(String.valueOf(num1));
break;
case "/":
num1 = num1 / num2;
resultsTextField.setText(String.valueOf(num1));
break;
default:
break;
}
}
});
mainPane.getChildren().addAll(resultsTextField, topRow
, middleRow, lowerRow, bottomRow);
primaryStage.setScene(mainScene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}