Android: How to fix accidental uncheck the checkbox of the parent node in the tree

I wrote the class to represent a tree file hierarchy. The main task - the ability to mark files and folders (using the checkbox). Has faced with such a problem: disappears check mark of the parent directory with the following sequence of actions:

0) Go to the root directory, check file (leave one directory unchecked)

1) Go to the unchecked directory and check any file (or more)

2) Return to a higher level and uncheck the directory,in which was carried out operation (1)

Return to a higher level and you'll see that check mark of the parent directory is unchecked (although there is at least one checked file in a root directory).

For many days I am in search of a problem. Maybe someone will notice the error. Thank you in advance.

Screenshots:

Bug

Normal state

The class:

public class FileTree {
    /* The name for pointer to the parent node */
    public static final String PARENT_DIR = "..";

    private String mName;
    private boolean mIsLeaf;
    private boolean mIsChecked = false;
    private long mSize;
    /* Number of checked children */
    private int childrenCheckNum = 0;
    private FileTree mParent;
    private Map<String, FileTree> mChildren = new LinkedHashMap<String, FileTree>();

    public FileTree(String name, long size, int type)
    {
        this(name, size, type, null);
    }

    public FileTree(String name, long size, int type, FileTree parent)
    {
        mName = name;
        mIsLeaf = type == FileNode.Type.FILE;
        mParent = parent;
        mSize = size;
    }

    public void addChild(FileTree node)
    {
        if (!mChildren.containsKey(node.getName())) {
            mChildren.put(node.getName(), node);
            mSize += node.size();
            if (mParent != null) {
                mParent.onChildAdd(node.size());
            }
        }
    }

    /*
     * Sending new child size up the tree.
     */

    private void onChildAdd(long size)
    {
        mSize += size;
        if (mParent != null) {
            mParent.onChildAdd(size);
        }
    }

    public boolean findChild(String name)
    {
        if (mChildren.containsKey(name)) {
            return true;
        }

        return false;
    }

    ...

    public boolean isChecked()
    {
        return mIsChecked;
    }

    public void setCheck(boolean check)
    {
        mIsChecked = check;

        /* Sending check change event up the parent */
        if (mParent != null && mParent.isChecked() != check) {
            mParent.onChildCheckChange(check);
        }

        /* Sending check change event down the tree */
        if (getChildrenCount() != 0) {
            childrenCheckNum = check ? getChildrenCount() : 0;

            for (FileTree node : mChildren.values()) {
                if (node.isChecked() != check) {
                    node.setCheck(check);
                }
            }
        }
    }

    /*
     * Sending check change events up the tree.
     */

    private void onChildCheckChange(boolean check)
    {
        if (check) {
            ++childrenCheckNum;
            mIsChecked = true;
        } else {
            if (childrenCheckNum > 0) {
                --childrenCheckNum;
            }

            /* Uncheck parent only if don't left selected children nodes */
            if (childrenCheckNum == 0) {
                mIsChecked = false;
            }
        }

        /* Sending check change event up the parent */
        if (mParent != null && mParent.isChecked() != check) {
            mParent.onChildCheckChange(check);
        }
    }
    ...
}