arraylist

问题 so I'm currently doing an exercise for college that has several optional parts (because we havn't done this in class yet), one of them being to use lists instead of arrays (so it'd be variable size) and another one printing the list sorted by points (I'll get to that now) So, I have the Player.java class which looks like this. public class Player { String name; String password; int chips; int points; public Player(String n, String pw, int c, int p) { name = n; password = pw; chips = c; points

问题 so I'm currently doing an exercise for college that has several optional parts (because we havn't done this in class yet), one of them being to use lists instead of arrays (so it'd be variable size) and another one printing the list sorted by points (I'll get to that now) So, I have the Player.java class which looks like this. public class Player { String name; String password; int chips; int points; public Player(String n, String pw, int c, int p) { name = n; password = pw; chips = c; points

问题 I am facing with this unwanted char to int conversion in a loop. Say I have this List of Characters and I want to remove one of those: List<Character> chars = new ArrayList<>(); chars.add('a'); chars.add('b'); chars.add('c'); chars.remove('a'); // or chars.remove('a'-'0'); so 'a' is interpreted as its int value and I'm getting an IndexOutOfBoundsException exception. Is there any easy workaround for this? 回答1: A char is promoted to an int , which takes precedence over autoboxing, so remove(int

问题 I am facing with this unwanted char to int conversion in a loop. Say I have this List of Characters and I want to remove one of those: List<Character> chars = new ArrayList<>(); chars.add('a'); chars.add('b'); chars.add('c'); chars.remove('a'); // or chars.remove('a'-'0'); so 'a' is interpreted as its int value and I'm getting an IndexOutOfBoundsException exception. Is there any easy workaround for this? 回答1: A char is promoted to an int , which takes precedence over autoboxing, so remove(int

问题 I am facing with this unwanted char to int conversion in a loop. Say I have this List of Characters and I want to remove one of those: List<Character> chars = new ArrayList<>(); chars.add('a'); chars.add('b'); chars.add('c'); chars.remove('a'); // or chars.remove('a'-'0'); so 'a' is interpreted as its int value and I'm getting an IndexOutOfBoundsException exception. Is there any easy workaround for this? 回答1: A char is promoted to an int , which takes precedence over autoboxing, so remove(int

问题 I have a question about using getter methods in java. Suppose I had this class: class Test { private ArrayList<String> array = new ArrayList<String>(); public ArrayList getArray() { return this.array; } public void initArray() { array.add("Test 1"); array.add("Test 2"); } } class Start { public static void main(String args[]) { initArray(); getArray().remove(0); } } My question is: Would the actual arraylist object be modified ("Test 1" removed from it)? I think I have seen this in places,

问题 I'm a beginner in Java and this time I'm trying to learn more by finding code examples and editing them, for example from this website. I have a JFrame and each time it (or more precise the JPanel in it) is clicked on, a circle is drawn which will grow/expand outwards like a water ripple. Each circle starts with a certain radius and will be removed or redrawn when reaching a bigger radius (I chose radius "r" from 10 to 200). I have two programs for this which almost work but are missing

问题 I'm a beginner in Java and this time I'm trying to learn more by finding code examples and editing them, for example from this website. I have a JFrame and each time it (or more precise the JPanel in it) is clicked on, a circle is drawn which will grow/expand outwards like a water ripple. Each circle starts with a certain radius and will be removed or redrawn when reaching a bigger radius (I chose radius "r" from 10 to 200). I have two programs for this which almost work but are missing

问题 I need to keep the order of my list of objects as it can be changed and reordered anytime in my webapp. In my model I have a array list of objects example objectList = [object1, object2, object3, object4] and I save the order of each object belonging to this instance to a Map example: order { "object1":4, "object2":2, "object3":1, "object4":3 } Therefore i want to sort my array according to its value in the map retrieved by the objects Id as the key: Expected result: [object3, object2,

问题 I need to create a list with different datatypes element, for example: {{10, 10}, "IT", 1, "Test", {100, 100}, "Test"} respectively: {object, string, integer, string, object, string} I have tried declaring it as list of objects or using Tuple(Of Object, String, Integer, String, Object, String) but when I give them the values, "Array initializer has too few dimensions" error occurs. The class where the variable is declared: Public Class SignatureResponse Public signature As Tuple(Of Object,