Question

我有时会遇到非常奇怪的例外:

04-18 18:08:08.121: E/AndroidRuntime(3031): Uncaught handler: thread main exiting due to uncaught exception
04-18 18:08:08.141: E/AndroidRuntime(3031): java.lang.ArrayIndexOutOfBoundsException
04-18 18:08:08.141: E/AndroidRuntime(3031): at java.util.ArrayList.addAll(ArrayList.java:257)
04-18 18:08:08.141: E/AndroidRuntime(3031): at com.zigzagworld.text.formatter.FormatManager.formatIfNeeded(FormatManager.java:185)
etc.

这在一名1.6名支持者身上发生。我的代码“addAll的行文是:

mTasksAbove.addAll(schedule.above);

我所能想象的唯一东西是同时进入<代码>。任务Above。然而,我非常谨慎地确保所有出入都在同一目标上同步进行。我想到的只有<代码>附件.above在执行<代码>add时经过修改的,但我认为这将产生<代码>目前版本的(加上,我认为我的代码并不这样)。是否有任何人知道我应该找什么东西?

http://www.ohchr.org。

根据Rykud的回答,我做了些微的挖掘,发现了确切的 b。在安的1.6种来源中,<代码>addAll方法指一种内部方法,即:growAtEnd。来源本身:

private void growAtEnd(int required) {
    int size = size();
    if (firstIndex >= required - (array.length - lastIndex)) {
        int newLast = lastIndex - firstIndex;
        if (size > 0) {
            System.arraycopy(array, firstIndex, array, 0, size);
            int start = newLast < firstIndex ? firstIndex : newLast;
            Arrays.fill(array, start, array.length, null);
        }
        firstIndex = 0;
        lastIndex = newLast;
    } else {
        int increment = size / 2;
        if (required > increment) {
            increment = required;
        }
        if (increment < 12) {
            increment = 12;
        }
        E[] newArray = newElementArray(size + increment);
        if (size > 0) {
            System.arraycopy(array, firstIndex, newArray, 0, size);
            /********************************************************
            * BUG! The next 2 lines of code should be outside the if *
            ********************************************************/
            firstIndex = 0;
            lastIndex = size;
        }
        array = newArray;
    }
}

The bug rears its ugly head when the list had been previously populated and then emptied, leaving size == 0 and firstIndex == lastIndex > 0 and you try to add a collection large enough that it doesn t fit between lastIndex and the current array size.

The bug is gone as of 2.2, when the addAll method was rewritten and growAtEnd disappeared from the class.

感谢雷库德为点人!

Answer 1

as of 1.5 the method addAll in arraylist was buggy, it was supposed to get fixed in a future realease, however I m not sure in wich one. To work around this you could create an Iterator for your collection and adding the elements one by one. Here is a little code to help:

Iterator<MyTypeofObjectToAdd> e = myArrayListToCopyFrom.iterator();
    while (e.hasNext()) {
      arrayListToAdd(e.next());
    }

and the IndexOutOfBounds exception is caused because you are trying to retrieve an item from a position where there is nothing.

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