arraylist

erase an object from canvas

由 …衆ロ難τιáo~ 提交于 2020-01-07 04:58:06
问题 I am trying to develop an application and i want the sprites to erase once they reach the end. I am using arraylist to handle my sprites on a canvas. I want the sprites to erase themselves from the canvas and from the arraylist once their x<0 (outside of the canvas) Please help me asap. Thanks This is my code so far for the erase command: for(Sprite sprite : rockSprites){ sprite.x -=10; if (Rect.intersects(sprite.dst, die)) { rockSprites.remove(this); currentAmountOfSprites--; try { Thread

How to write and retrieve objects arraylist to file?

由 我只是一个虾纸丫 提交于 2020-01-07 04:36:07
问题 I have an object arraylist, can someone please help me by telling me the most efficient way to write AND retrieve an object from file? Thanks. My attempt public static void LOLadd(String ab, String cd, int ef) throws IOException { MyShelf newS = new MyShelf(); newS.Fbooks = ab; newS.Bbooks = cd; newS.Cbooks = ef; InfoList.add(newS); FileWriter fw; fw = new FileWriter("UserInfo.out.txt"); PrintWriter outt = new PrintWriter(eh); for (int i = 0; i <InfoList.size(); i++) { String ax = InfoList

Is it there a better way to Search HashMap from ArrayList

由 家住魔仙堡 提交于 2020-01-07 04:12:27
问题 I am trying to implement Searching in ListView . My ListView is comprised of HashMap in ArrayList and I managed to implement the logic but I guess there is much object and memory allocation in my approach each time the text change. Therefore I am looking for less memory allocated logic to search in my ListView with HashMap in ArrayList @Override public void onTextChanged(CharSequence s, int start, int before, int count) { //textlength = searchBar.getText().length(); //text_sort.clear();

Is it there a better way to Search HashMap from ArrayList

由 霸气de小男生 提交于 2020-01-07 04:12:09
问题 I am trying to implement Searching in ListView . My ListView is comprised of HashMap in ArrayList and I managed to implement the logic but I guess there is much object and memory allocation in my approach each time the text change. Therefore I am looking for less memory allocated logic to search in my ListView with HashMap in ArrayList @Override public void onTextChanged(CharSequence s, int start, int before, int count) { //textlength = searchBar.getText().length(); //text_sort.clear();

All elements are replaced by last element in an arraylist of hashmap

由 痴心易碎 提交于 2020-01-07 03:10:11
问题 I have values as Question Q-id Q1 1 Q2 2 ...and so on I want to retrieve them by calling a function. So i used an arraylist of HashMaps as follows.. public ArrayList<HashMap<String,String>> getAllQuestions(Integer id) { try { HashMap<String,String> QuesList = new HashMap<String,String>(); ArrayList<HashMap<String, String>> QuestionArrayList = new ArrayList<HashMap<String, String>>(); // Select All Query String selectQuery = <some query here>; cursor = mDb.rawQuery(selectQuery, null); //

Writing an ArrayList of non-string objects to file

由 假装没事ソ 提交于 2020-01-07 02:15:50
问题 EDIT: I solved the problem, I forgot to close the ObjectOutputStream. 'doh! I'll leave the question just in case someone wants to propose a more elegant option, which would be much appreciated. I currently am trying to write a class called phonebook to file, which contains an ArrayList of objects called PhonebookEntry. Here is the Phonebook class: import java.util.ArrayList; import java.io.*; public class Phonebook implements Serializable private static final long serialVersionUID = 1;

Java高阶:ArrayList源码分析

由 只谈情不闲聊 提交于 2020-01-06 22:06:15
* ArrayList源码分析 * jdk7和jdk8版本有一些不同 首先，不管7版本还是8版本，ArrayList底层存储没有改变 private transient Object[] elementData; 在使用的时候，最简单的使用方式为： ArrayList list = new ArrayList(); 1.所以首先看ArrayList源码中的空参构造器 public ArrayList() { this(10); } public ArrayList(int initialCapacity) { super(); if (initialCapacity < 0) throw new IllegalArgumentException("Illegal Capacity: "+ initialCapacity); this.elementData = new Object[initialCapacity]; } 从源码可以看出，空参的时候，初始化的长度就是为10。 即new ArrayList();会创建一个长度为10的Object类型 数组 2.在ArrayList中的add方法： 第一次添加的时候，size大小为0 public boolean add(E e) { ensureCapacityInternal(size + 1); // Increments

Sorting an ArrayList based on a class data member's data member

由 狂风中的少年 提交于 2020-01-06 21:23:20
问题 So, I have a class which contains another class object as its data member. I have created an ArrayList based on this prototype. Here is the code: package Stack; import java.io.*; import java.util.*; class Point { int x; int y; Point(int x, int y) { this.x = x; this.y = y; } } public class MergeInterval { Point P; MergeInterval() {} public static void main(String args[]) { ArrayList<Point> arr = new ArrayList<Point>(); // Point p = new Point(6,8); arr.add(new Point(6,8)); arr.add(new Point(1,9

How to sum values in arrayList

由 社会主义新天地 提交于 2020-01-06 21:05:37
问题 I am trying to create a console application where i take input from the user asking for total area then i ask the user the amount of structures that our in that area and then I store the values in the list what I am trying t do is substract the total area by structure are but i cant sum the values from the List package lawn; import java.util.Scanner; import java.util.List; import java.util.ArrayList; /** * * @author norbe */ public class Lawn { private double lenght, width; private double

How to sum values in arrayList

由 此生再无相见时 提交于 2020-01-06 21:05:01
问题 I am trying to create a console application where i take input from the user asking for total area then i ask the user the amount of structures that our in that area and then I store the values in the list what I am trying t do is substract the total area by structure are but i cant sum the values from the List package lawn; import java.util.Scanner; import java.util.List; import java.util.ArrayList; /** * * @author norbe */ public class Lawn { private double lenght, width; private double
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