ArrayList.add() 导致 OutOfMemory 错误？

Question

今天我第一次遇到 OutOfMemory 错误。我正在尝试将一些数据的移动平均值计算到 ArrayList 中，并在第一个 .add() 步骤中发生崩溃。方法如下

  public ArrayList<Long> getNdaySMA(List<HistoricalQuote> history, int range){
    long sum =0;
    long SMA = 0;
    ArrayList<Long> SMAs = new ArrayList<Long>();
    //realRange is made due to the differences in defining "range in calculation vs speech
    //a 10 day range for day 9 is actually from prices of day0 to day9, inclusive
    int realRange =range-1;

    //First step, add in placeholder 0s for the days within the range that have no value
    //so if 10 day range, we have 0-> 9
    for (int i=0;i<i+realRange;i++){
        SMAs.add(i,0L);
    }

    //Next, actually calculate the SMAs for i.e. day 10
    for (int i =0;i<history.size();i++){
        //should be k<10, 0......9 = 10 days
        for(int k=i+realRange;k==i;k--){
            //Sum first from k=i+range-1 , go down to i.
            //This should give us a value of RANGE
            sum +=history.get(k).getClose().longValue();


        }
        //after summing up, we add calculate SMA and add it to list of SMAs
        SMA = sum/range;
        //we add the corresponding SMA to index i+range, made up of values calculated from before it
        //to excel
        SMAs.add(i+realRange,SMA);
        sum =0;
    }

    return SMAs;
}

堆栈跟踪如下

java.lang.OutOfMemoryError
                                                                at java.util.ArrayList.add(ArrayList.java:154)
                                                                at com.xu.investo.MethodDatabase.getNdaySMA(MethodDatabase.java:46)

其中第46行指的是

SMAs.add(i,0L);

这个错误是不是因为使用了 Long 数字格式？欢迎提出任何建议。

Answer 1

我想我已经确定了问题所在。

我可能在这一行创建了一个无限循环

 for (int i=0;i<i+realRange;i++){
    SMAs.add(i,0L);
}

Answer 2

看起来像无限循环：

for (int i=0;i<i+realRange;i++)

i 将始终小于 i+realRange 因为 realRange 大于零：

ArrayList.add() 导致 OutOfMemory 错误？

ArrayList.add() causing OutOfMemory error?

android

memory-management

add

arraylist

out-of-memory