안드로이드 프로그래밍 005 - Notepadv1

Notepadv1 은 http://developer.android.com 에서 tutorials에서 볼 수 있는 소스다.
그냥 완성된 Notepad를 보고 분석하려다가 머리에 쥐가나서 처음부터 따라해 보기로 했다.
(역시 난 천재는 아닌가보다. 열심히 한 계단씩 가는수 밖에 ...)

tutorial에서는 완전하지 않은 소스를 완성해 가며 배울 수 있다.

기능은 단순하다. MENU 버튼을 누르면 Note1, Note2 ... 이런식으로 늘어난다.
그러나 SQLite에 저장하고 저장된 데이터를 불러오고 ListView에 뿌려주는 조금 복잡하다. (지금까지 해본 것 중에)
 
1. layout을 잡자. layout 이 두개다. 하나는 메인이고 하나는 ListView에 끼워넣어질 layout이다.
notepad_list.xml

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content" > <ListView android:id="@android:id/list" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <TextView android:id="@android:id/empty" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/no_notes" /> </LinearLayout>
notes_row.xml

<?xml version="1.0" encoding="utf-8"?> <TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/text1" android:layout_width="wrap_content" android:layout_height="wrap_content" />
2. Notepadv1.java - 메인 Activity

package com.android.demo.notepad1; import android.app.ListActivity; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.os.Bundle; import android.view.Menu; import android.view.MenuItem; import android.widget.SimpleCursorAdapter; public class Notepadv1 extends ListActivity { private int mNoteNumber = 1; private NotesDbAdapter mDbHelper; public static final int INSERT_ID = Menu.FIRST; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.notepad_list); // layout 장착 mDbHelper = new NotesDbAdapter(this); // NotesDbAdapter class 확인 필요 // Activity = context 항상 명심... mDbHelper.open(); // open()메소드를 실행함으로써 // SQLiteDatabase mDb 멤버 필드를 초기화 한다. 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}; SimpleCursorAdapter notes = new SimpleCursorAdapter(this, R.layout.notes_row, c, from , to); setListAdapter(notes); } @Override public boolean onCreateOptionsMenu(Menu menu) { // menu 버튼을 누르면 나오는 아이템등록 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(); } }

3. NotesDbAdapter.java - SQLite 에 붙는 클래스 

package com.android.demo.notepad1; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.SQLException; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import android.util.Log; public class NotesDbAdapter { 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); // SQLiteOpenHelper(Context context, // String name, // SQLiteDatabase.CursorFactory factory, // int version) // 생성자. } @Override public void onCreate(SQLiteDatabase db) { // 추상 클래스인 SQLiteOpenHelper의 구현되어야할 메소드 db.execSQL(DATABASE_CREATE); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // 추상 클래스인 SQLiteOpenHelper의 구현되어야할 메소드 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; } }
4. strings.xml

<?xml version="1.0" encoding="utf-8"?> <resources> <string name="app_name">Notepad v1</string> <string name="no_notes">No Notes Yet</string> <string name="menu_insert">Add Item</string> </resources>
Manifest.xml 파일은 수정할 필요가 없다.

다음은 v2로 가죠...