Notepad Tutorial (Exercise 1) ④

2012年6月19日火曜日

Notepad Tutorial (Exercise 1) ④

ステップ 11

createNote メソッドを追加します。
Notepadv1.javaを開き以下のように変更します。

/*
 * Copyright (C) 2008 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.demo.notepad1;

import android.app.ListActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class Notepadv1 extends ListActivity {
    public static final int INSERT_ID = Menu.FIRST;
    private int mNoteNumber = 1;
    private NotesDbAdapter mDbHelper;

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

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

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

        return super.onOptionsItemSelected(item);
    }

    private void createNote() {
        String noteName = "Note " + mNoteNumber++;
        mDbHelper.createNote(noteName, "");
        fillData();
    }
}

createNote では、mNoteNumberをインクリメントし、ノートのタイトルを作成して、NotesDbAdapterのcreateNoteを呼んでいます。

ステップ 12

fillData メソッドを追加します。
Notepadv1.javaを開き以下のように変更します。

/*
 * Copyright (C) 2008 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.demo.notepad1;

import android.app.ListActivity;
import android.database.Cursor;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.SimpleCursorAdapter;

public class Notepadv1 extends ListActivity {
    public static final int INSERT_ID = Menu.FIRST;
    private int mNoteNumber = 1;
    private NotesDbAdapter mDbHelper;

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

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

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

        return super.onOptionsItemSelected(item);
    }

    private void createNote() {
        String noteName = "Note " + mNoteNumber++;
        mDbHelper.createNote(noteName, "");
        fillData();
    }

    private void fillData() {
        // Get all of the notes from the database and create the item list
        Cursor c = mDbHelper.fetchAllNotes();
        startManagingCursor(c);

        String[] from = new String[] { NotesDbAdapter.KEY_TITLE };
        int[] to = new int[] { R.id.text1 };

        // Now create an array adapter and set it to display using our row
        SimpleCursorAdapter notes =
            new SimpleCursorAdapter(this, R.layout.notes_row, c, from, to);
        setListAdapter(notes);
    }
}

fetchAllNotesにてデータベースから、全レコードを取得し、startManagingCursorへCursorを登録しリソースの管理を行います。
その後、表示するテキスト(ノートのタイトル)の配列と、テキストを表示するView(ステップ 5で作成したTextView)を定義したintの配列を作成します。
作成した配列をSimpleCursorAdapter に渡し、リスト表示を行います。

なお、SimpleCursorAdapterはAndroid 2.3.3(APIレベル 10)では非推奨となったみたいですが、勉強不足で代替の実装方法も思い浮かばないため、ここではSimpleCursorAdapterを使用します。

This constructor is deprecated.
This option is discouraged, as it results in Cursor queries being performed on the application's UI thread and thus can cause poor responsiveness or even Application Not Responding errors. As an alternative, use LoaderManager with a CursorLoader.

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2012年6月19日火曜日