我有一份笔记申请表。用户可以创建新注解或更改现有注解。
在这个应用程序中，我尝试在用户更改现有笔记时自动保存笔记。因此，我使用 textWatcher 我打电话给 saveNotes() 中的方法 onTextChanged() 文本的方法。因此，每当用户从文本中添加或删除任何字符时，我打算在这里保存注解。

var ide: Int? = null  //Global Variable

//in OnCreate()
if(intent.getBooleanExtra("isViewOrUpdate", false)){
            viewOrOpenedNote = intent.getSerializableExtra("note") as Note?
            ide = viewOrOpenedNote?.id

在以上两个代码示例中。。整个想法就是制造变量 ide 充当一个检查器，即如果用户正在创建一个新的便笺，它将返回null；否则，如果用户已打开一个现有便笺以查看或编辑便笺，它将存储便笺的id。
下面是textwatcher

title_edit_text.addTextChangedListener((object : TextWatcher {
            override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {}
            override fun onTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
                saveNote()   // here I 
            }
            override fun afterTextChanged(p0: Editable?) {}
        }))

savenote（）

private fun saveNote() {
                val note = Note()
                note.setTitle(Title)

                if (ide != null) {
                    note.setId(ide!!)  // Here I am assigning the note id to `ide` in case the 
                                         `saveNote()` is called when user has opened an existing note. If 
                                          this is a new note then ide will be null automatically.
                }
                class SaveNotes : AsyncTask<Void, Void, Void>() {
                    override fun doInBackground(vararg void: Void?): Void? {
                        NotesDatabase.getDatabase(applicationContext).noteDao().insertNote(note)
                        return null
                    }

                    override fun onPostExecute(result: Void?) {
                        super.onPostExecute(result)
                        ide = note.id               //This is because: If user has added a first 
                                                     character in new note, then after that an id will be 
                                                     assigned to this new database, whenever 
                                                    `saveNote()` method is called again after text change 
                                                     I need to save the changed note to the same existing 
                                                     id. I hope I am clear.

                     //***UPDATE***After much contemplation I have found out 
                       that here lies the problem! changing the value of ide by 
                       simply `ide = note.id` will always give null value for new 
                       note, as this id is not received from the created note, 
                       but from the blank note instance I created above. 
                    }
                }
                SaveNotes().execute()
}

问题：即使采取了上述预防措施，每次我更改一个便笺时，都会创建同一便笺的多个示例。例子：
假设我键入：你好
我得到的结果是5个不同id的音符，文字如下：
h//id=5
他//id=4
赫尔//id=3
地狱//id=2
你好//id=1
注解.java

@Dao
public interface NoteDao {

    @Query("SELECT * FROM note ORDER BY id DESC")
    List<Note> getAllNotes();

    @Insert(onConflict = OnConflictStrategy.REPLACE)
    void insertNote(Note note);

    @Delete
    void delete(Note note);
}

注解.java

@Entity(tableName = "note")
public class Note implements Serializable {

    @PrimaryKey(autoGenerate = true)
    private int id;

    @ColumnInfo(name = "title")

注解数据库.java

public static synchronized NotesDatabase getDatabase(Context context)
    {
        if(notesDatabase == null){
           notesDatabase =  Room.databaseBuilder(context
            , NotesDatabase.class,
                    "note_db"
                    )
                   .addMigrations(MIGRATION_1_2)
                   .build();
        }
        return notesDatabase;
    }

    public abstract NoteDao noteDao();