Android 记事本NotePad
起初接触Android的时候用Eclipse写的小应用，后面手动移植到了Android Studio中，可以新建，查看，删除便签等，今天整理一下代码，完整的代码可以在我的GitHub上看到，链接在文末。
DbHelper：
package com.zms.notepad;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import java.util.ArrayList;
import java.util.List;
/**
* Created by AlexZhou on 2015/2/3.
* 11:12
*/
public class NoteDbHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 2;
private static final String DATABASE_NAME = "notes_db";
private static final String NOTE_TABLE_NAME = "note";
private static final String NOTE_COL_ID = "_id";
private static final String NOTE_COL_TITLE = "title";
private static final String NOTE_COL_CONTENT = "content";
private static final String NOTE_COL_CREATED = "created";
private static final String NOTE_COL_MODIFIED = "modified";
private static final String[] NOTE_COL_PROJECTION = new String[] {
NOTE_COL_ID,
NOTE_COL_TITLE,
NOTE_COL_CONTENT,
NOTE_COL_CREATED,
NOTE_COL_MODIFIED
};
public NoteDbHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Create table
@Override
public void onCreate(SQLiteDatabase db) {
String createNoteTableSql = "CREATE TABLE " + NOTE_TABLE_NAME + " ("
+ NOTE_COL_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + NOTE_COL_TITLE
+ " TEXT," + NOTE_COL_CONTENT + " TEXT," + NOTE_COL_CREATED
+ " INTEGER," + NOTE_COL_MODIFIED + " INTEGER" + ");";
db.execSQL(createNoteTableSql);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + NOTE_TABLE_NAME);
// Create tables again
onCreate(db);
}
// Add new note
public int addNote(Note note) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(NOTE_COL_TITLE, note.getTitle());
values.put(NOTE_COL_CONTENT, note.getContent());
values.put(NOTE_COL_CREATED, note.getCreated());
values.put(NOTE_COL_MODIFIED, note.getModified());
// Insert to database
long rowId = db.insert(NOTE_TABLE_NAME, null, values);
// Close the database
db.close();
return (int) rowId;
}
// Get one note
public Note getNote(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(NOTE_TABLE_NAME, NOTE_COL_PROJECTION,
NOTE_COL_ID + "=?", new String[] { String.valueOf(id) }, null,
null, null, null);
if (cursor != null)
cursor.moveToFirst();
Note note = new Note(cursor.getInt(0), cursor.getString(1),
cursor.getString(2), cursor.getLong(3), cursor.getLong(4));
return note;
}
// Get all notes
public List getAllNotes() {
List noteList = new ArrayList();
String selectQuery = "SELECT * FROM " + NOTE_TABLE_NAME;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Note note = new Note(cursor.getInt(0), cursor.getString(1),
cursor.getString(2), cursor.getLong(3),
cursor.getLong(4));
noteList.add(note);
} while (cursor.moveToNext());
}
// return contact list
return noteList;
}
public Cursor getAllNotesCursor() {
String selectQuery = "SELECT * FROM " + NOTE_TABLE_NAME;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
return cursor;
}
public int updateNote(Note note) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(NOTE_COL_TITLE, note.getTitle());
values.put(NOTE_COL_CONTENT, note.getContent());
values.put(NOTE_COL_CREATED, note.getCreated());
values.put(NOTE_COL_MODIFIED, note.getModified());
return db.update(NOTE_TABLE_NAME, values,
NOTE_COL_ID + "=?", new String[] { String.valueOf(note.getId()) });
}
public void deleteNote(int noteId) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(NOTE_TABLE_NAME, NOTE_COL_ID + "=?",new String[] { String.valueOf(noteId) } );
db.close();
}
public void deleteAllNotes() {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(NOTE_TABLE_NAME, null, null);
db.close();
}
}
新建和修改便签：
package com.zms.notepad;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
/**
* Created by AlexZhou on 2015/2/3.
* 11:14
*/
public class NoteNew extends Activity {
private EditText etTitle; //便签标题
private EditText etContent; //便签内容
private Button btnCancel;
private Button btnSave;
private int _noteId; //便签ID
private NoteDbHelper _db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.note_new);
etTitle = (EditText) findViewById(R.id.etTitle);
etContent = (EditText) findViewById(R.id.etContent);
btnCancel = (Button) findViewById(R.id.btnCancel);
btnSave = (Button) findViewById(R.id.btnSave);
btnCancel.setOnClickListener(new OnClickListenerImp());
btnSave.setOnClickListener(new OnClickListenerImp());
_db = new NoteDbHelper(this);
Intent intent = getIntent();
_noteId = intent.getIntExtra(NoteList.EXTRA_NOTE_ID, -1);
if (_noteId > 0) {
Note note = _db.getNote(_noteId);
etTitle.setText(note.getTitle());
etContent.setText(note.getContent());
}
}
private class OnClickListenerImp implements View.OnClickListener {
@Override
public void onClick(View v) {
if (v == btnCancel) {
Toast.makeText(NoteNew.this, "天启提示：放弃新建便签", Toast.LENGTH_SHORT).show();
finish();
} else if (v == btnSave) {
String titleVoid = etTitle.getText().toString();
String contentVoid = etContent.getText().toString();
if (titleVoid.equals("") || contentVoid.equals("")) {
Toast.makeText(NoteNew.this, "天启提示：标题或内容为空", Toast.LENGTH_SHORT).show();
} else {
ToDatabase(); //插入数据库
Toast.makeText(NoteNew.this, "天启提示：便签保存成功", Toast.LENGTH_SHORT).show();
finish();
}
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.note_new_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_exit) {
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
android.os.Process.killProcess(android.os.Process.myPid());
return true;
} else if (id == R.id.action_about) {
Intent intent = new Intent(this, About.class);
startActivity(intent);
return true;
}
return super.onOptionsItemSelected(item);
}
public final int ToDatabase() {
String title = etTitle.getText().toString();
String content = etContent.getText().toString();
int newNoteId = -1;
if (_noteId > 0) {
Note note = _db.getNote(_noteId);
note.setTitle(title);
note.setContent(content);
note.setModified(Long.valueOf(System.currentTimeMillis()));
_db.updateNote(note);
} else {
Note newNote = new Note(title, content);
newNoteId = _db.addNote(newNote);
}
return newNoteId;
}
}
查看便签：
package com.zms.notepad;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
public class Main extends ActionBarActivity {
private ImageView ivLogo;
private Button btnView;
private Button btnNew;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ivLogo = (ImageView) findViewById(R.id.ivLogo);
btnView = (Button) findViewById(R.id.btnView);
btnNew = (Button) findViewById(R.id.btnNew);
btnView.setOnClickListener(new OnClickListenerImp());
btnNew.setOnClickListener(new OnClickListenerImp());
ivLogo.setAlpha(50); //Alpha 0-255,设置主页Logo的透明度
}
private class OnClickListenerImp implements View.OnClickListener {
@Override
public void onClick(View v) {
if (v == btnView) {
Intent intent = new Intent(Main.this, NoteList.class);
startActivity(intent);
} else if (v == btnNew) {
Intent intent = new Intent(Main.this, NoteNew.class);
startActivity(intent);
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_about) {
//点击菜单兰“关于”按钮后触发
Intent intent = new Intent(this, About.class);
startActivity(intent);
return true;
} else if (id == R.id.action_exit) {
//点击菜单兰“退出”按钮后触发
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
android.os.Process.killProcess(android.os.Process.myPid());
return true;
}
return super.onOptionsItemSelected(item);
}
}
转载请注明出处：周木水的CSDN博客 http://blog.csdn.net/zhoumushui