Android 如何在记事本中查看笔记

我已经完成了记事本教程v3，但有一件事我不知道如何使我的笔记在视图模式而不是编辑模式下打开

我用按钮和其他东西做了自己的记事本，但还是看不见。。 助手类

public static final String KEY_TITLE = "title";
public static final String KEY_BODY = "body";
public static final String KEY_ROWID = "_id";

private static final String TAG = "NotesDbAdapter";
private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;

/**
 * Database creation sql statement
 */
private static final String DATABASE_CREATE =
    "create table notes (_id integer primary key autoincrement, "
    + "title text not null, body text not null);";

private static final String DATABASE_NAME = "data";
private static final String DATABASE_TABLE = "notes";
private static final int DATABASE_VERSION = 2;

private final Context mCtx;

private static class DatabaseHelper extends SQLiteOpenHelper {

    DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        db.execSQL(DATABASE_CREATE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                + newVersion + ", which will destroy all old data");
        db.execSQL("DROP TABLE IF EXISTS notes");
        onCreate(db);
    }
}

/**
 * Constructor - takes the context to allow the database to be
 * opened/created
 * 
 * @param ctx the Context within which to work
 */
public NotesDbAdapter(Context ctx) {
    this.mCtx = ctx;
}

/**
 * Open the notes database. If it cannot be opened, try to create a new
 * instance of the database. If it cannot be created, throw an exception to
 * signal the failure
 * 
 * @return this (self reference, allowing this to be chained in an
 *         initialization call)
 * @throws SQLException if the database could be neither opened or created
 */
public NotesDbAdapter open() throws SQLException {
    mDbHelper = new DatabaseHelper(mCtx);
    mDb = mDbHelper.getWritableDatabase();
    return this;
}

public void close() {
    mDbHelper.close();
}


/**
 * Create a new note using the title and body provided. If the note is
 * successfully created return the new rowId for that note, otherwise return
 * a -1 to indicate failure.
 * 
 * @param title the title of the note
 * @param body the body of the note
 * @return rowId or -1 if failed
 */
public long createNote(String title, String body) {
    ContentValues initialValues = new ContentValues();
    initialValues.put(KEY_TITLE, title);
    initialValues.put(KEY_BODY, body);

    return mDb.insert(DATABASE_TABLE, null, initialValues);
}

/**
 * Delete the note with the given rowId
 * 
 * @param rowId id of note to delete
 * @return true if deleted, false otherwise
 */
public boolean deleteNote(long rowId) {

    return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}

/**
 * Return a Cursor over the list of all notes in the database
 * 
 * @return Cursor over all notes
 */
public Cursor fetchAllNotes() {

    return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_TITLE,
            KEY_BODY}, null, null, null, null, null);
}

/**
 * Return a Cursor positioned at the note that matches the given rowId
 * 
 * @param rowId id of note to retrieve
 * @return Cursor positioned to matching note, if found
 * @throws SQLException if note could not be found/retrieved
 */
public Cursor fetchNote(long rowId) throws SQLException {

    Cursor mCursor =

        mDb.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
                KEY_TITLE, KEY_BODY}, KEY_ROWID + "=" + rowId, null,
                null, null, null, null);
    if (mCursor != null) {
        mCursor.moveToFirst();
    }
    return mCursor;

}

/**
 * Update the note using the details provided. The note to be updated is
 * specified using the rowId, and it is altered to use the title and body
 * values passed in
 * 
 * @param rowId id of note to update
 * @param title value to set note title to
 * @param body value to set note body to
 * @return true if the note was successfully updated, false otherwise
 */
public boolean updateNote(long rowId, String title, String body) {
    ContentValues args = new ContentValues();
    args.put(KEY_TITLE, title);
    args.put(KEY_BODY, body);

    return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}

public class Notepadv3 extends ListActivity {
private static final int ACTIVITY_CREATE=0;
private static final int ACTIVITY_EDIT=1;

private static final int INSERT_ID = Menu.FIRST;
private static final int DELETE_ID = Menu.FIRST + 1;

private NotesDbAdapter mDbHelper;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.notes_list);
    mDbHelper = new NotesDbAdapter(this);
    mDbHelper.open();
    fillData();
    registerForContextMenu(getListView());
}

private void fillData() {
    Cursor notesCursor = mDbHelper.fetchAllNotes();
    startManagingCursor(notesCursor);

    // Create an array to specify the fields we want to display in the list (only TITLE)
    String[] from = new String[]{NotesDbAdapter.KEY_TITLE};

    // and an array of the fields we want to bind those fields to (in this case just text1)
    int[] to = new int[]{R.id.text1};

    // Now create a simple cursor adapter and set it to display
    SimpleCursorAdapter notes = 
        new SimpleCursorAdapter(this, R.layout.notes_row, notesCursor, from, to);
    setListAdapter(notes);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    super.onCreateOptionsMenu(menu);
    menu.add(0, INSERT_ID, 0, R.string.menu_insert);
    return true;
}

@Override
public boolean onMenuItemSelected(int featureId, MenuItem item) {
    switch(item.getItemId()) {
        case INSERT_ID:
            createNote();
            return true;
    }

    return super.onMenuItemSelected(featureId, item);
}

@Override
public void onCreateContextMenu(ContextMenu menu, View v,
        ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);
    menu.add(0, DELETE_ID, 0, R.string.menu_delete);
}

@Override
public boolean onContextItemSelected(MenuItem item) {
    switch(item.getItemId()) {        
        case DELETE_ID:
            AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
            mDbHelper.deleteNote(info.id);
            fillData();
            return true;
    }
    return super.onContextItemSelected(item);
}

private void createNote() {
    Intent i = new Intent(this, NoteEdit.class);
    startActivityForResult(i, ACTIVITY_CREATE);
}

@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);
    Intent i = new Intent(this, NoteEdit.class);
    i.putExtra(NotesDbAdapter.KEY_ROWID, id);
    startActivityForResult(i, ACTIVITY_EDIT);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
    super.onActivityResult(requestCode, resultCode, intent);
    fillData();
}

}

主类

public static final String KEY_TITLE = "title";
public static final String KEY_BODY = "body";
public static final String KEY_ROWID = "_id";

private static final String TAG = "NotesDbAdapter";
private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;

/**
 * Database creation sql statement
 */
private static final String DATABASE_CREATE =
    "create table notes (_id integer primary key autoincrement, "
    + "title text not null, body text not null);";

private static final String DATABASE_NAME = "data";
private static final String DATABASE_TABLE = "notes";
private static final int DATABASE_VERSION = 2;

private final Context mCtx;

private static class DatabaseHelper extends SQLiteOpenHelper {

    DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        db.execSQL(DATABASE_CREATE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                + newVersion + ", which will destroy all old data");
        db.execSQL("DROP TABLE IF EXISTS notes");
        onCreate(db);
    }
}

/**
 * Constructor - takes the context to allow the database to be
 * opened/created
 * 
 * @param ctx the Context within which to work
 */
public NotesDbAdapter(Context ctx) {
    this.mCtx = ctx;
}

/**
 * Open the notes database. If it cannot be opened, try to create a new
 * instance of the database. If it cannot be created, throw an exception to
 * signal the failure
 * 
 * @return this (self reference, allowing this to be chained in an
 *         initialization call)
 * @throws SQLException if the database could be neither opened or created
 */
public NotesDbAdapter open() throws SQLException {
    mDbHelper = new DatabaseHelper(mCtx);
    mDb = mDbHelper.getWritableDatabase();
    return this;
}

public void close() {
    mDbHelper.close();
}


/**
 * Create a new note using the title and body provided. If the note is
 * successfully created return the new rowId for that note, otherwise return
 * a -1 to indicate failure.
 * 
 * @param title the title of the note
 * @param body the body of the note
 * @return rowId or -1 if failed
 */
public long createNote(String title, String body) {
    ContentValues initialValues = new ContentValues();
    initialValues.put(KEY_TITLE, title);
    initialValues.put(KEY_BODY, body);

    return mDb.insert(DATABASE_TABLE, null, initialValues);
}

/**
 * Delete the note with the given rowId
 * 
 * @param rowId id of note to delete
 * @return true if deleted, false otherwise
 */
public boolean deleteNote(long rowId) {

    return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}

/**
 * Return a Cursor over the list of all notes in the database
 * 
 * @return Cursor over all notes
 */
public Cursor fetchAllNotes() {

    return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_TITLE,
            KEY_BODY}, null, null, null, null, null);
}

/**
 * Return a Cursor positioned at the note that matches the given rowId
 * 
 * @param rowId id of note to retrieve
 * @return Cursor positioned to matching note, if found
 * @throws SQLException if note could not be found/retrieved
 */
public Cursor fetchNote(long rowId) throws SQLException {

    Cursor mCursor =

        mDb.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
                KEY_TITLE, KEY_BODY}, KEY_ROWID + "=" + rowId, null,
                null, null, null, null);
    if (mCursor != null) {
        mCursor.moveToFirst();
    }
    return mCursor;

}

/**
 * Update the note using the details provided. The note to be updated is
 * specified using the rowId, and it is altered to use the title and body
 * values passed in
 * 
 * @param rowId id of note to update
 * @param title value to set note title to
 * @param body value to set note body to
 * @return true if the note was successfully updated, false otherwise
 */
public boolean updateNote(long rowId, String title, String body) {
    ContentValues args = new ContentValues();
    args.put(KEY_TITLE, title);
    args.put(KEY_BODY, body);

    return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}

public class Notepadv3 extends ListActivity {
private static final int ACTIVITY_CREATE=0;
private static final int ACTIVITY_EDIT=1;

private static final int INSERT_ID = Menu.FIRST;
private static final int DELETE_ID = Menu.FIRST + 1;

private NotesDbAdapter mDbHelper;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.notes_list);
    mDbHelper = new NotesDbAdapter(this);
    mDbHelper.open();
    fillData();
    registerForContextMenu(getListView());
}

private void fillData() {
    Cursor notesCursor = mDbHelper.fetchAllNotes();
    startManagingCursor(notesCursor);

    // Create an array to specify the fields we want to display in the list (only TITLE)
    String[] from = new String[]{NotesDbAdapter.KEY_TITLE};

    // and an array of the fields we want to bind those fields to (in this case just text1)
    int[] to = new int[]{R.id.text1};

    // Now create a simple cursor adapter and set it to display
    SimpleCursorAdapter notes = 
        new SimpleCursorAdapter(this, R.layout.notes_row, notesCursor, from, to);
    setListAdapter(notes);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    super.onCreateOptionsMenu(menu);
    menu.add(0, INSERT_ID, 0, R.string.menu_insert);
    return true;
}

@Override
public boolean onMenuItemSelected(int featureId, MenuItem item) {
    switch(item.getItemId()) {
        case INSERT_ID:
            createNote();
            return true;
    }

    return super.onMenuItemSelected(featureId, item);
}

@Override
public void onCreateContextMenu(ContextMenu menu, View v,
        ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);
    menu.add(0, DELETE_ID, 0, R.string.menu_delete);
}

@Override
public boolean onContextItemSelected(MenuItem item) {
    switch(item.getItemId()) {        
        case DELETE_ID:
            AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
            mDbHelper.deleteNote(info.id);
            fillData();
            return true;
    }
    return super.onContextItemSelected(item);
}

private void createNote() {
    Intent i = new Intent(this, NoteEdit.class);
    startActivityForResult(i, ACTIVITY_CREATE);
}

@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);
    Intent i = new Intent(this, NoteEdit.class);
    i.putExtra(NotesDbAdapter.KEY_ROWID, id);
    startActivityForResult(i, ACTIVITY_EDIT);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
    super.onActivityResult(requestCode, resultCode, intent);
    fillData();
}

---

}您可以创建一个新的活动。如果要使其快速且脏，请复制和修改NoteEdit类中的内容。如果您有时间，您应该花一些时间考虑设计，并遵循代码大师建议的“复制粘贴编码是一种糟糕的设计”

找到一个按钮或某个可以触发该活动的地方

public void onClick(View v) {
Intent i = new Intent(mCtx, NoteView.class);
    i.putExtra(NotesDbAdapter.KEY_ROWID, id);
    mCtx.startActivity(i);
}

---

如您所知，您可以通过在

意图中使用“extras”将数据发送到
活动。要确定数据是处于“查看”模式还是“编辑”模式，只需发送一个
boolean
值来指示它是哪个。然后，接收
活动
可以检查
布尔值
“额外”，并根据该标志禁用或启用所有可编辑视图。
记事本应用程序##[免费记事本是在智能手机上保存笔记的简单、优雅、简单的方法。
曾几何时，你必须在纸记事本上记下笔记。]

公共类FontTypePreference扩展了DialogPreference{
私有列表字体=null；
选择私人int；
公共FontTypePreference（上下文、属性集属性）{
超级（上下文，attrs）；
SharedPreferences sharedPref=首选项管理器
.GetDefaultSharedReferences（getContext（））；
String font=sharedPref.getString（“font”，“Monospace”）；
如果（字体等于（“衬线”））
所选=1；
else if（字体等于（“无衬线”））
选择=2；
其他的
所选=0；
}
受保护的无效onPrepareDialogBuilder（AlertDialog.Builder）{
//数据已更改，请通知以便刷新UI！
setTitle（“选择字体类型”）；
setPositiveButton（“确定”，新的DialogInterface.OnClickListener（）{
public void onClick（对话框接口对话框，int whichButton）{
Editor=PreferenceManager.GetDefaultSharedReferences(
getContext（））.edit（）；
如果（所选==0）
编辑器.putString（“字体”、“单空格”）；
else if（所选==1）
编辑器.putString（“字体”、“衬线”）；
其他的
putString（“字体”，“无衬线”）；
commit（）；
notifyChanged（）；
}
});
builder.setNegativeButton（“取消”，
新建DialogInterface.OnClickListener（）{
public void onClick（对话框接口对话框，int whichButton）{
//在取消时不执行任何操作
}
});
//加载字体名称
String[]ArrayOffnts={“单空间”、“衬线”、“无衬线”}；
字体=数组.asList（ArrayOffnts）；
FontTypeArrayAdapter=新的FontTypeArrayAdapter（getContext（），
android.R.layout.simple_list_item_single_choice，字体）；
builder.setSingleChoiceItems（适配器，选定，
新建DialogInterface.OnClickListener（）{
public void onClick（DialogInterface dialog，int which）{
所选=哪个；
}
});
} 
公共类FontTypeArrayAdapter扩展了ArrayAdapter{
公共FontTypeArrayAdapter（上下文上下文、int资源、，
列出对象）{
超级（上下文、资源、对象）；
}
公共视图getView（int位置、视图转换视图、视图组父视图）{
视图v=super.getView（位置、转换视图、父级）；
最终文本视图电视=（文本视图）v；
最终字符串选项=tv.getText（）.toString（）；
如果（选项等于（“衬线”））
设置字体（字体衬线）；
else if（option.equals（“无衬线”））
tv.setTypeface（字体无衬线）；
else if（option.equals（“Monospace”））
tv.setTypeface（Typeface.MONOSPACE）；
tv.setTextColor（Color.BLACK）；
设置填充（10,3,3,3）；
返回v；
}
}

}
请显示代码的相关部分，以及来自LogcatCopy和paste编码的错误消息（如果存在）。好吧，我更新了我的答案。很抱歉，我没有时间为他设计整个项目，所以我复制并粘贴了给他一条行会路线。你至少可以建议一些高层次的替代设计，这是我在写答案时的意图；-）当我第一次看到这个问题时，我的想法和你们的回答一样，但我认为初学者如果看到了什么，他们会更容易，他们已经看到了。不管怎样，我不明白为什么我被否决了。我的答案绝对正确，也没那么糟糕。