小编dem*_*ro1的帖子

你好我正在研究一个项目,我正在尝试将NSUInteger添加到NSMutableArray.我是Objective-C和C的新手.当我运行应用程序时,NSLog显示为null.

我很感激任何人都能提供的帮助.

这是我的代码

-(NSMutableArray *)flipCardAtIndex:(NSUInteger)index
{
    Card *card = [self cardAtIndex:index];
    [self.flipCardIndexes addObject:index];

    if(!card.isUnplayable)
    {
        if(!card.isFaceUp)
        {
            for(Card *otherCard in self.cards)
            {
                if(otherCard.isFaceUp && !otherCard.isUnplayable)
                {
                    int matchScore = [card match:@[otherCard]];
                    if(matchScore)
                    {
                        otherCard.unplayable = YES;
                        card.unplayable = YES;
                        self.score += matchScore * MATCH_BONUS;
                    }
                    else 
                    {
                        otherCard.faceUp = NO;
                        self.score -=MISMATCH_PENALTY;
                    }
                    break;
                }
            }
            self.score -=FLIP_COST;
        }
        card.faceUp = !card.isFaceUp;
    }
    NSLog(@"%@",self.flipCardIndexes[self.flipCardIndexes.count-1]);
    return self.flipCardIndexes;
}

我正在研究一个项目,并且我被教导在构造函数中实例化变量.我在使用ArrayList思想时遇到了一些麻烦.您能否提出一些最佳实践,我是否需要使用实例变量定义ArrayList,或者我可以在构造函数中执行此操作.谢谢你的建议!我有一个我正在谈论的内容的例子:

//imports
import java.util.*;
import java.lang.*;

public class ArrayListConstructorDemo
{
//instance variables/attributes

String string;
List<String> list;// for example does this line need to say List<String> list = new ArrayList<String>();

//constructors
public ArrayListConstructorDemo()
{
    String string = "null";
    List<String> list = new ArrayList<String>();//is there anyway I can do this here instead of 6 lines up?
}//end default constructor
public ArrayListConstructorDemo(String string,List<String> list)
{
    this.string = string;
    this.list = list;
}//end generic constructor

//observers/getters/accessors
 public String getString(){return string;}//end method getString()
 public List<String> …