Java 对自定义对象列表排序时出现NullPointerException

我想根据字段对自定义列表进行排序。我的列表有大约125条记录，因为它是静态的

Collections.sort(receivedSOSModelArrayList, new Comparator<ReceivedSOSModel>() {
    @Override
    public int compare(ReceivedSOSModel receivedSOSModel, ReceivedSOSModel t1) {
        return receivedSOSModel.getReceivedSOSFrom().compareTo(t1.getReceivedSOSFrom());
    }
});

---

在比较之前添加空检查：

Collections.sort(receivedSOSModelArrayList, new Comparator<ReceivedSOSModel>() {
    @Override
    public int compare(ReceivedSOSModel receivedSOSModel, ReceivedSOSModel t1) {
        if (receivedSOSModel == null || receivedSOSModel.getReceivedSOSFrom() == null) {
            Log.v("first", "NULL");
            return -1;  //null values will be displayed at bottom in sorted list
        }

        if (t1 == null || t1.getReceivedSOSFrom() == null ) {
            Log.v("second", "NULL");
            return 1;  //null values will be displayed at bottom in sorted list
        }

        return receivedSOSModel.getReceivedSOSFrom().compareTo(t1.getReceivedSOSFrom());
    }
});

Collections.sort（receivedSOSModelArrayList，newcomparator（）{
@凌驾
公共int比较（ReceivedSOSModel ReceivedSOSModel，ReceivedSOSModel t1）{
if（receivedSOSModel==null | | receivedSOSModel.getReceivedSOSFrom（）==null）{
Log.v（“第一个”、“空”）；
return-1；//空值将显示在排序列表的底部
}
if（t1==null | | t1.getReceivedSOSFrom（）==null）{
Log.v（“第二个”、“空”）；
返回1；//空值将显示在排序列表的底部
}
返回receivedSOSModel.getReceivedSOSFrom（）.compareTo（t1.getReceivedSOSFrom（））；
}
});

确保列表中的所有元素都不是空的是，它们不是空的。选中我的错误谢谢列表元素可能不为null，但

元素。GetReceivedSoFrom（）

至少用于其中一个元素。是的，它们不为null。检查我的错误谢谢

Collections.sort(receivedSOSModelArrayList, new Comparator<ReceivedSOSModel>() {
    @Override
    public int compare(ReceivedSOSModel receivedSOSModel, ReceivedSOSModel t1) {
        if (receivedSOSModel == null || receivedSOSModel.getReceivedSOSFrom() == null) {
            Log.v("first", "NULL");
            return -1;  //null values will be displayed at bottom in sorted list
        }

        if (t1 == null || t1.getReceivedSOSFrom() == null ) {
            Log.v("second", "NULL");
            return 1;  //null values will be displayed at bottom in sorted list
        }

        return receivedSOSModel.getReceivedSOSFrom().compareTo(t1.getReceivedSOSFrom());
    }
});