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这是一个名为 note 的类的定义（没有大多数函数）。

   public class Note
    {
        private String text;
        String fileName = "";
        NoteManager noteManager = null;
        List<String> hyperlinks = new ArrayList<String>();

        public static final int BUFFER_SIZE = 512;

        public Note(NoteManager noteManager) {
            this.noteManager = noteManager;
            this.text = "";
        }

        public Note(NoteManager noteManager, String content) {
            this(noteManager);
            if (content == null)
                setText("");
            else
                setText(content);
        }

        public Note(NoteManager noteManager, CharSequence content) {
            this(noteManager, content.toString());
        }

        ....some functions....

        public static Note newFromFile(NoteManager noteManager, Context context,
            String filename) throws IOException
        {

        FileInputStream inputFileStream = context.openFileInput(filename);
        StringBuilder stringBuilder = new StringBuilder();
        byte[] buffer = new byte[BUFFER_SIZE];
        int len;
        while ((len = inputFileStream.read(buffer)) > 0)

         {
            String line = new String(buffer, 0, len);
            stringBuilder.append(line);

            buffer = new byte[Note.BUFFER_SIZE];
        }

        Note n = new Note(noteManager, stringBuilder.toString().trim());
        n.fileName = filename;

        inputFileStream.close();

        return n;
    }

       .... some functions attributed to this class

}

这些笔记由一个名为 NoteManager.java 的类管理，我在下面对其进行了缩写：

public class NoteManager
{
    Context context=null;
    ArrayList<Note> notes = new ArrayList<Note>();

    ..... some functions...

    public void addNote(Note note)
    {
        if (note == null || note.noteManager != this ||   notes.contains(note)) return;
        note.noteManager = this;
        notes.add(note);    
        try
        {
            note.saveToFile(context);
        } catch (IOException e)
        {
            e.printStackTrace();
        }
    }


    ....some functions....

    public void loadNotes()
    {
        String[] files = context.fileList();
        notes.clear();
        for (String fname:files)
        {
            try
            {
                notes.add(Note.newFromFile(this, context, fname));
            } catch (IOException e)
            {
                e.printStackTrace();
            }
        }

    }
}

public void addNote(Note note)
    {
        if (note == null || notes.contains(note)) return;
        note.noteManager = this;
        notes.add(note);    
        try
        {
            note.saveToFile(context);
        } catch (IOException e)
        {
            e.printStackTrace();
        }
    }

我试图弄清楚为什么这个记事本应用程序在应用程序完全关闭然后重新打开时会创建随机的新笔记，但是我看不出问题是什么。我已经删除了所有似乎与问题无关的功能，所以逻辑错误一定在某个地方。

如何找到我猜测的某种循环引用或缺乏检查？

4

1 回答 1

1

Android 通常使用带有多字节字符的 UTF-8。如果您偏离 ASCII，在任意字节子数组上创建新字符串可能会在开始和结束时出现问题。

public static Note newFromFile(NoteManager noteManager, Context context,
        String filename) throws IOException
{
    Path path = Paths.get(filename);
    byte[] bytes = Files.readAllBytes(path);
    String content = new String(bytes,  "UTF-8");

    Note n = new Note(noteManager, content.trim());
    n.fileName = filename;
    noteManager.add(n); // One registration?
    return n;
}

拥有多个节点实例的问题可能需要在 newFromFile 中添加，或者可能需要额外检查：

public void addNote(Note note)
{
    if (note == null || note.noteManager != this || notes.contains(note)) {
        return;
    }
    note.noteManager = this;
    notes.add(note);

最后，必须明确定义注释。

public class Note extends Comparable<Note> {

    private NoteManager noteManager:
    private final String content; // Immutable.

    public NoteManager(NoteManager noteManager, String content) {
        this.noteManager = noteManager;
        this.content = content;
    }
    ... compare on the immutable content
    ... hashCode on content

不能改变内容，并且在字符串内容上进行比较，意味着音符不能翻倍，改变集合，混淆集合顺序。

于 2016-01-30T22:30:13.677 回答