如何比较每个位置的两个数组字符串

Question

I am new to java, and I have this problem; I am working with a webservice from android where I send a request and I get an answer formatted like this string: 1-0,2-0,3-0,4-0,5-0,6-0,7-0,8-0,12-0,13-0 where the number before the "-" means the number of my button and the number after "-" means the button status. I split this string into an array like this:

String  buttons = "1-0,2-0,3-0,4-0,5-0,6-0,7-0,8-0,13-0,14-0";
String[] totalButtons = buttons.split(",");

then I make a new request to get the status of my buttons and I get this

String status = "1-0,2-0,3-2,4-0,5-4,6-0,7-4,8-0,9-2,10-1,13-4,14-2";
String[] statusButtons = status.split(",");

The number of the buttons are going to be the same all time; in this case 10 buttons. The problem that I have is how to compare each element of the two arrays if they can change their status every two seconds and I receive more buttons than the first time and I have to change their status with the new value. For example the first element of the array one is equal to the first element of the second array so there is no problem, but the first array does not have two elements in the second array in this case 9-2,10-1 so they should be deleted. The final result should be like this

String  buttons =     "1-0,2-0,3-0,4-0,5-0,6-0,7-0,8-0,13-0,14-0";
String status =       "1-0,2-0,3-2,4-0,5-4,6-0,7-4,8-0,9-2,10-1,13-4,14-2";
String finalButtons = "1-0,2-0,3-2,4-0,5-4,6-0,7-4,8-0,13-4,14-2";

Answer 1

Here's an idea to get you started;

Map<String,String> buttonStatus = new HashMap<String,String>();

for (String button : totalButtons) {
    String parts[] = button.split("-");
    buttonStatus.put(parts[0], parts[1]);
}

for (String button : statusButtons) {
    String parts[] = button.split("-");
    if (buttonStatus.containsKey(parts[0])) {
        buttonStatus.put(parts[0], parts[1]);
    }
    // Java 8 has a "replace" method that will change the value only if the key
    // already exists; unfortunately, Android doesn't support it
}

The result will be a map whose keys are taken from the original totalButtons , and whose values will be taken from statusButtons if present. You can go through the keys and values in the Map to get the results, but they won't be in order; if you want them to be in the same order as totalButtons , go through totalButtons again and use buttonStatus.get to get each value.

The javadoc for Map is here .

Answer 2

I would split up each of those again and then compare those values.

ex:

String[] doubleSplit = totalButtons[index].split("-"); // "1-0" -> {"1", "0"}

Answer 3

import java.util.HashMap;
import java.util.Map;

/**
 * @author Davide
 */
public class test {
    static Map map;

    public static void main(String[] args) {
        // init value
        String buttons = "1-0,2-0,3-0,4-0,5-4,6-0,7-0,8-0,13-0,14-0";
        String[] keys = buttons.split("(-[0-9]*,*)");

        init(keys);

        // new value
        String status = "1-0,2-0,3-2,4-0,5-4,6-0,7-4,8-0,9-2,10-1,13-4,14-2";
        String[] statusButtons = status.split(",");

        update(statusButtons);
        print();
    }

    public static void init(String[] keys) {
        map = new HashMap<Integer, Integer>();
        for (String k : keys) {
            map.put(Integer.valueOf(k), 0);
        }
    }

    public static void update(String[] statusButtons) {
        for (String state : statusButtons) {
            String[] split = state.split("-");
            int k = Integer.valueOf(split[0]);
            int v = Integer.valueOf(split[1]);
            if (map.containsKey(k)) {
                map.put(k, v);
            }
        }
    }

    public static void print() {
        String out = "";
        for (Object k : map.keySet()) {
            out += k + "-" + map.get(k) + ",";
        }
        System.out.println(out.substring(0, out.length() - 1));
    }
}