Java - 无限循环单例类方法调用

Question

我有一个关于单例类的问题。当我调用方法 next() 时，我预计 mProcessIndex 会增加，但实际上，它不会增加，因此会导致堆栈溢出错误。那么，问题是修改 mProcessIndex 值的正确方法是什么？

代码如下:

public class HomePopupDisplayManager {
    private static HomePopupDisplayManager sInstance;
    private List<WeakReference<HomePopupMessage>> mMessages;
    private int mProcessIndex;

    private HomePopupDisplayManager() {
        mMessages = new ArrayList<>();
        mProcessIndex = 0;
    }

    public static synchronized HomePopupDisplayManager getInstance() {
        if (sInstance == null) {
            sInstance = new HomePopupDisplayManager();
        }

        return sInstance;
    }

        public void register(@NonNull HomePopupMessage message, @IntRange(from = 0) int order) {
            mMessages.add(order, new WeakReference<>(message));
    }

    public void next() {
        if (mProcessIndex >= 0 && mProcessIndex < mMessages.size()) {
            HomePopupMessage message = mMessages.get(mProcessIndex).get();
            if (message != null) {
                next();
                mProcessIndex++;
            }
        }
    }
}

Answer 1

问题出在:

next();
mProcessIndex++;

应该是:

mProcessIndex++;
next();