从JTextField获取数字作为数组用于Java中的标准偏差计算

Question

I'm new to Java programming and right now I'm making a Calculation app where you can input numbers to one textfield and get the result of Mean, Median, Mode and Standard Deviation. the problem I'm facing right now is in Standard Deviation part. I've created a method to calculate the Standard Deviation based on the numbers inputted on the one textfield in app using the code below:

static double Q2(ArrayList<Integer> input) {
    Collections.sort(input);

    ArrayList<Double> input2 = new ArrayList<>();
    double sum = 0;
    double sum2 = 0;
    double sd = 0;

    for (int i = 0; i < input.size(); i++) {
        sum = sum + input.get(i);
    }

    double mean = sum / input.size();

    for (int i = 0; i < input.size(); i++) {
        input2.add((Math.pow((input.get(i) - mean), 2)));
    }

    for (int i = 0; i < input2.size(); i++) {
        sum2 = sum2 + input2.get(i);
    }

    double mean2 = sum2 / input2.size();

    sd = Math.sqrt(mean2);

    return sd;
}

and this is my actionListener code:

standardevButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            String [] numString = inputField.getText().trim().split(" ");
            outputLabel.setText(getStandarDev(getValueSet(numString)));
        }

but the problem I have now is I don't know how to get the numbers inputted in the textfield and show the result of Standard Deviation calculation when I press the Standard Deviation button in app.

This is the interface of the application

below is the code for main method and Standard Deviation:

public static void main(String [] args)
{
    TugasMatematika runIt = new TugasMatematika();
}
public static String getStandarDev(double [] nums) 
{

}

I've been searching for the answers for this problem quite a while so I'll be really really grateful if someone can help me to solve this problem.

Answer 1

在标准偏差按钮上使用鼠标单击侦听器，然后使用set方法将文本字段设置为所需答案的文本

Answer 2

This line of code here:

String [] numString = inputField.getText().trim().split(" ");

Actually gets every space seperated numbers on your textfield. However, these data are in string data type so you would have to parse them one by one to a numerical data type such a double or integer. Let me give you an idea here:

for each String variable in my String array
receivingIntegerVariable = Integer.parseInt(stringVariable) or
receivingDoubleVariable = Double.parseDouble(stringVariable)

On the other hand, if you would like to display the actual result of computation after button click, try to attach an event listener to the button and have a handling method that would update your JTextField with the result you had with your computation.

JTextFieldX.setText(resultGoesHere);

EDIT: It seems like you're using a label for display your results. The same concept applies in here.