有没有办法提取＆＃34;提取＆＃34; ArrayList中的单个字符串？ 我已将字符串存储在ArrayList中，并希望将它们打印到控制台。 我知道我可以使用for循环，但它并不那么简单。我正在尝试创建基于列的打印，并且我使用一种方法（由＃34创建; CandiedOrange＆＃34;此处为堆栈溢出），它将逗号分隔的字符串作为输入。
它基本上是做什么的;它根据每列中字符串的长度创建列间距。 （全部归入＆＃34; CandiedOrange＆＃34;）
List<List<String>> lines = new ArrayList<>();
List<Integer> maxLengths = new ArrayList<>();
int numColumns = -1;
public Columns addLine(String... line) {
if (numColumns == -1){
numColumns = line.length;
for(int i = 0; i < numColumns; i++) {
maxLengths.add(0);
}
}
if (numColumns != line.length) {
throw new IllegalArgumentException();
}
for(int i = 0; i < numColumns; i++) {
maxLengths.set( i, Math.max( maxLengths.get(i), line[i].length() ) );
}
lines.add( Arrays.asList(line) );
return this;
}
我想要打印的列数在编译期间是未知的，因为用户在运行时输入列数1-5。所以我想我可以使用ArrayLists作为行，并使用addLine（）方法与行的每个arraylists。
如果有更好的解决方法，我会非常乐意知道。
编辑：
从一开始：
我创造了一个拥有1-5名玩家的Yahtzee游戏。每个播放器都由类＆＃34;播放器＆＃34;
的实例定义public class Player {
private String name;
private int ones;
private int twos;
private int threes;
private int fours;
private int fives;
private int sixes;
private int threeofakind;
private int fourofakind;
private int fullhouse;
private int smallstraight;
private int largestraight;
private int chance;
private int yahtzee;
private int totalscore;
public int getOnes() {
return ones;
}
public void setOnes(int ones) {
this.ones = ones;
}
public int getTwos() {
return twos;
}
public void setTwos(int twos) {
this.twos = twos;
}
public int getThrees() {
return threes;
}
public void setThrees(int threes) {
this.threes = threes;
}
public int getFours() {
return fours;
}
public void setFours(int fours) {
this.fours = fours;
}
public int getFives() {
return fives;
}
public void setFives(int fives) {
this.fives = fives;
}
public int getSixes() {
return sixes;
}
public void setSixes(int sixes) {
this.sixes = sixes;
}
public int getThreeofakind() {
return threeofakind;
}
public void setThreeofakind(int threeofakind) {
this.threeofakind = threeofakind;
}
public int getFourofakind() {
return fourofakind;
}
public void setFourofakind(int fourofakind) {
this.fourofakind = fourofakind;
}
public int getFullhouse() {
return fullhouse;
}
public void setFullhouse(int fullhouse) {
this.fullhouse = fullhouse;
}
public int getSmallstraight() {
return smallstraight;
}
public void setSmallstraight(int smallstraight) {
this.smallstraight = smallstraight;
}
public int getLargestraight() {
return largestraight;
}
public void setLargestraight(int largestraight) {
this.largestraight = largestraight;
}
public int getChance() {
return chance;
}
public void setChance(int chance) {
this.chance = chance;
}
public int getYahtzee() {
return yahtzee;
}
public void setYahtzee(int yahtzee) {
this.yahtzee = yahtzee;
}
public int getTotalscore() {
return totalscore;
}
public void setTotalscore(int totalscore) {
this.totalscore = totalscore;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
我实现了MVC结构（尽我所能），这意味着我有一个View类，其中包含一个显示主控制台列记分板的方法。 （方法未完成）
public void displayMainScoreBoard(ArrayList<Player> playerList) {
Columns col = new Columns(); //Instance of column class.
ArrayList<String> Name = new ArrayList<>();
ArrayList<Integer> Ones = new ArrayList<>();
ArrayList<Integer> Twos = new ArrayList<>();
ArrayList<Integer> Threes = new ArrayList<>();
ArrayList<Integer> Fours = new ArrayList<>();
ArrayList<Integer> Fives = new ArrayList<>();
ArrayList<Integer> Sixes = new ArrayList<>();
ArrayList<Integer> Threeofakind = new ArrayList<>();
ArrayList<Integer> Fourofakind = new ArrayList<>();
ArrayList<Integer> Fullhouse = new ArrayList<>();
ArrayList<Integer> Smallstraight = new ArrayList<>();
ArrayList<Integer> Largestraight = new ArrayList<>();
ArrayList<Integer> Chance = new ArrayList<>();
ArrayList<Integer> Yahtzee = new ArrayList<>();
ArrayList<Integer> Totalscore = new ArrayList<>();
for (Player p : playerList) { //For every player, append their category data.
Name.add(p.getName());
Ones.add(p.getOnes());
Twos.add(p.getTwos());
Threes.add(p.getThrees());
Fours.add(p.getFours());
Fives.add(p.getFives());
Sixes.add(p.getSixes());
Threeofakind.add(p.getThreeofakind());
Fourofakind.add(p.getFourofakind());
Fullhouse.add(p.getFullhouse());
Smallstraight.add(p.getSmallstraight());
Largestraight.add(p.getLargestraight());
Chance.add(p.getChance());
Yahtzee.add(p.getYahtzee());
Totalscore.add(p.getTotalscore());
}
}
还有CandiedOrange的完整专栏课程。 （同样，我声称他的代码没有权利。）
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class Columns {
List<List<String>> lines = new ArrayList<>();
List<Integer> maxLengths = new ArrayList<>();
int numColumns = -1;
public Columns addLine(String... line) {
if (numColumns == -1){
numColumns = line.length;
for(int i = 0; i < numColumns; i++) {
maxLengths.add(0);
}
}
if (numColumns != line.length) {
throw new IllegalArgumentException();
}
for(int i = 0; i < numColumns; i++) {
maxLengths.set( i, Math.max( maxLengths.get(i), line[i].length() ) );
}
lines.add( Arrays.asList(line) );
return this;
}
public void print(){
System.out.println( toString() );
}
public String toString(){
String result = "";
for(List<String> line : lines) {
for(int i = 0; i < numColumns; i++) {
result += pad( line.get(i), maxLengths.get(i) + 1 );
}
result += System.lineSeparator();
}
return result;
}
private String pad(String word, int newLength){
while (word.length() < newLength) {
word += " ";
}
return word;
}
}
如何在视图中将我的ArrayLists的字符串传递给addLine（）方法？
答案 0 :(得分：0)
...将逗号分隔的字符串作为输入。
从技术上讲，它需要一个数组（more in this Java tutorial on varargs）。但是，Java允许您在使用离散参数调用它时自动创建该数组。
由于它接受一个数组，并且你有一个ArrayList，你可以使用toArray(T[])轻松地将一个数组传递给它：
List<List<String>> linesToAdd = /*...*/;
// ...
for (List<String> line : linesToAdd) {
addLine(line.toArray(new String[line.size()]));
}
也就是说，修改addLine直接接受List<String>将是微不足道的（以及良好的编码练习）。
答案 1 :(得分：0)
我相信你根本不应该使用那个Columns课程。
您的大多数列表都是数字而不是字符串。数字最好显示右对齐。并且您想要显示的每个行中唯一的字符串是播放器名称。
因此，不是将所有数据复制到各种列表，并假设对于大多数数字，你有一个合理的宽度，他们将无法通过（4位数？6位数？），那么你的任务就变成了：
您可以将这些作为方法添加到Player类，以便查找给定播放列表的最大名称长度：
public static int maxNameLength( List<? extends Player> players ) {
int maxLength = 0;
for ( Player player : players ) {
int currLength = player.getName().length();
if ( currLength > maxLength ) {
maxLength = currLength;
}
}
return maxLength;
}
现在，可以使用String.format使用Formatter以正确填充的方式显示当前播放器。
为了简洁起见，假设我只想显示名字，Yahtzee和总分。您在Player：
public String getScoreLine( int maxLength ) {
String format = "%-" + maxLength + "s %6d %6d";
return String.format( format, getName(), getYahtzee(), getTotalscore() );
}
第一部分的作用是为字符串创建左对齐字段。因此，如果maxLength是20，则格式为%-20s %6d %6d。这些数字将在6个字符宽的字段中右对齐显示，名称左对齐并填充为20个字符。
现在，您可以循环显示列表并显示如下：
int maxNameLength = Player.maxNameLength( playerList );
for ( Player p : playerList ) {
System.out.println( p.getScoreLine( maxNameLength ) );
}
注意：如果你想将getScoreLine方法放在你的View而不是Player类中（因为你试图做MVC），你需要把它作为一个播放器。参数。
答案 2 :(得分：0)
我遵循了不使用列类的建议，即使我想尝试使用它。我对解决方案进行了半硬编码。
playerList是游戏中存在的玩家列表。和类别从另一个类获得，以检查评分时哪些类别是可选择的。 （不可用时显示为X，可选时显示为O。）
case Value of
IntVal x -> doWhatYouWantToDoWithInteger x
BoolVal x -> doWhatYouWantToDoWithBoolean x
打印出来：
public void displayMainScoreBoard(ArrayList<Player> playerList, ArrayList<Boolean> categories) {
List<String> Name = new ArrayList<>();
List<String> Ones = new ArrayList<>();
List<String> Twos = new ArrayList<>();
List<String> Threes = new ArrayList<>();
List<String> Fours = new ArrayList<>();
List<String> Fives = new ArrayList<>();
List<String> Sixes = new ArrayList<>();
List<String> Threeofakind = new ArrayList<>();
List<String> Fourofakind = new ArrayList<>();
List<String> Fullhouse = new ArrayList<>();
List<String> Smallstraight = new ArrayList<>();
List<String> Largestraight = new ArrayList<>();
List<String> Chance = new ArrayList<>();
List<String> Yahtzee = new ArrayList<>();
List<String> Totalscore = new ArrayList<>();
for (Player p : playerList) { //For every player, append their category data.
Name.add(p.getName());
Ones.add(String.valueOf(p.getOnes()));
Twos.add(String.valueOf(p.getTwos()));
Threes.add(String.valueOf(p.getThrees()));
Fours.add(String.valueOf(p.getFours()));
Fives.add(String.valueOf(p.getFives()));
Sixes.add(String.valueOf(p.getSixes()));
Threeofakind.add(String.valueOf(p.getThreeofakind()));
Fourofakind.add(String.valueOf(p.getFourofakind()));
Fullhouse.add(String.valueOf(p.getFullhouse()));
Smallstraight.add(String.valueOf(p.getSmallstraight()));
Largestraight.add(String.valueOf(p.getLargestraight()));
Chance.add(String.valueOf(p.getChance()));
Yahtzee.add(String.valueOf(p.getYahtzee()));
Totalscore.add(String.valueOf(p.getTotalscore()));
}
boolean checkones = categories.get(0); //Checkers for which categories are available to score in.
boolean checktwos = categories.get(1);
boolean checkthrees = categories.get(2);
boolean checkfours = categories.get(3);
boolean checkfives = categories.get(4);
boolean checksixes = categories.get(5);
boolean checkthreeofkind = categories.get(6);
boolean checkfourofkind = categories.get(7);
boolean checkfullhouse = categories.get(8);
boolean checksmallstraight = categories.get(9);
boolean checklargestraight = categories.get(10);
boolean checkchance = categories.get(11);
boolean checkyahtzee = categories.get(12);
System.out.println("| "+ "| | Name " + stringBuilder(Name));
System.out.println("|" + isPickable(checkones) + "|1. | Ones " + stringBuilder(Ones));
System.out.println("|" + isPickable(checktwos) + "|2. | Twos " + stringBuilder(Twos));
System.out.println("|" + isPickable(checkthrees) + "|3. | Threes " + stringBuilder(Threes));
System.out.println("|" + isPickable(checkfours) + "|4. | Fours " + stringBuilder(Fours));
System.out.println("|" + isPickable(checkfives) + "|5. | Fives " + stringBuilder(Fives));
System.out.println("|" + isPickable(checksixes) + "|6. | Sixes " + stringBuilder(Sixes));
System.out.println("|" + isPickable(checkthreeofkind) + "|7. | Three of a kind " + stringBuilder(Threeofakind));
System.out.println("|" + isPickable(checkfourofkind) + "|8. | Four of a kind " + stringBuilder(Fourofakind));
System.out.println("|" + isPickable(checkfullhouse) + "|9. | Full House " + stringBuilder(Fullhouse));
System.out.println("|" + isPickable(checksmallstraight) + "|1. | Small Straight " + stringBuilder(Smallstraight));
System.out.println("|" + isPickable(checklargestraight) + "|11.| Large Straight " + stringBuilder(Largestraight));
System.out.println("|" + isPickable(checkchance) + "|12.| Chance " + stringBuilder(Chance));
System.out.println("|" + isPickable(checkyahtzee) + "|13.| Yahtzee " + stringBuilder(Yahtzee));
System.out.println("| "+ "| | Total Score " + stringBuilder(Totalscore));
}
/*
* Method for creating the lines for the scoreboard.
*/
public String stringBuilder(List<String> arrIn) {
StringBuilder sb = new StringBuilder();
for (String s : arrIn) {
sb.append("|");
sb.append(s);
sb.append(pad(s));
}
return sb.toString();
}
/*
* Method for padding the spaces between columns.
*/
public String pad(String s) {
int space = 15;
int sLength = s.length();
String retPad = "";
int temp = space - sLength;
for (int i = 0; i <= temp ; i++) {
retPad += " ";
}
return retPad;
}
public String isPickable(boolean b) {
if (b == true) {
return "O";
}
else {
return "X";
}
}
只要用户没有输入可笑的长名称，这种方式就会很好看。这可以通过要求用户输入较短的名称（昵称）来解决。 无论如何，谢谢你的帮助！