Android数据存储--SQLite 存储方式应用(日记管理系统)

 







values/Strings.xml内容：
<?xml version="1.0" encoding="utf-8"?>
<resources>
   <string name="app_name">日记管理系统</string>
    <string name="menu_insert">添加一篇新日记</string>
    <string name="menu_delete">删除一篇日记</string>
    <string name="title">标题</string>
    <string name="body">内容</string>
    <string name="confirm">确定</string>
    <string name="edit_diary">编辑日记</string>
</resources>

 layout/diary_edit.xml内容：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="vertical" android:layout_width="fill_parent"
 android:layout_height="fill_parent">
 <LinearLayout android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content">
  <TextView android:layout_width="wrap_content"
   android:layout_height="wrap_content" android:text="@string/title"
   android:padding="2px" />
  <EditText android:id="@+id/title"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content" android:layout_weight="1" />
 </LinearLayout>
 <TextView android:layout_width="wrap_content"
  android:layout_height="wrap_content" android:text="@string/body" />
 <EditText android:id="@+id/body" android:layout_width="fill_parent"
  android:layout_height="fill_parent" android:layout_weight="1"
  android:scrollbars="vertical" android:gravity="top" />
 <Button android:id="@+id/confirm" android:text="@string/confirm"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content" />
</LinearLayout>

layout/diary_list.xml内容：
<?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="@+id/android:list"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content" />
 <TextView android:id="@+id/android:empty"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content" android:text="您还没有开始写日记呢!点击下边的Menu按钮开始写日记吧:)" />
</LinearLayout>

layout/diary_row.xml内容：
<?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="@+id/android:list"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content" />
 <TextView android:id="@+id/android:empty"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content" android:text="您还没有开始写日记呢!点击下边的Menu按钮开始写日记吧:)" />
</LinearLayout>

AndroidManifest.xml的内容：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="SQLiteSave.Jcuckoo"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".SQLiteTest"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
  <activity android:name=".ActivityDiaryEdit"/>
    </application>
    <uses-sdk android:minSdkVersion="4" />
</manifest>

 程序入口SQLiteTest.java：
public class SQLiteTest 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 DiaryDbAdapter mDbHelper;
 private Cursor mDiaryCursor;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
     setContentView(R.layout.diary_list);
     //数据操作接口
  mDbHelper = new DiaryDbAdapter(this);
  mDbHelper.open();
  renderListView();
    }
    //获取并显示所有记录
    private void renderListView() {
  mDiaryCursor = mDbHelper.getAllNotes();
  startManagingCursor(mDiaryCursor);
  //指定需要显示表的字段
  String[] from = new String[] { DiaryDbAdapter.KEY_TITLE,DiaryDbAdapter.KEY_CREATED };
  //将指定字段“标题”和“创建时间”，在指定的“R.layout.diary_row”界面中的ListView、TextView标签显示出来
  int[] to = new int[] { R.id.text1, R.id.created };
  SimpleCursorAdapter notes = new SimpleCursorAdapter(this,R.layout.diary_row, mDiaryCursor, from, to);
  //将SimpleCursorAdapter 和本类继承的ListActivity 里边的ListView 绑定起来，至此在界面当中才会显示出列表来。
  setListAdapter(notes);
 }

    //创建“Menu按钮”菜单：添加记录、删除记录
 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
  super.onCreateOptionsMenu(menu);
  menu.add(0, INSERT_ID, 0, R.string.menu_insert);
  menu.add(0, DELETE_ID, 0, R.string.menu_delete);
  return true;
 }
 //菜单事件：当点击添加时，进入添加界面；当点击删除时，删掉当前被选中的记录
 @Override
 public boolean onMenuItemSelected(int featureId, MenuItem item) {
  switch (item.getItemId()) {
  case INSERT_ID:
   createDiary();
   return true;
  case DELETE_ID:
   mDbHelper.deleteDiary(getListView().getSelectedItemId());
   renderListView();
   return true;
  }
  return super.onMenuItemSelected(featureId, item);
 }
 //激活添加记录界面，2个界面间无数据传输
 private void createDiary() {
  Intent i = new Intent(this, ActivityDiaryEdit.class);
  startActivityForResult(i, ACTIVITY_CREATE);
 }

 //list列表被选择事件：当记录被选择时，切换到修改该记录的界面
 @Override
 // 需要对position和id进行一个很好的区分
 // position指的是点击的这个ViewItem在当前ListView中的位置
 // 每一个和ViewItem绑定的数据，肯定都有一个id，通过这个id可以找到那条数据。
 protected void onListItemClick(ListView l, View v, int position, long id) {
  super.onListItemClick(l, v, position, id);
  Cursor c = mDiaryCursor;
  c.moveToPosition(position);
  //先将要传输的数据填充到Intent对象中，再切换到编辑界面
  Intent i = new Intent(this, ActivityDiaryEdit.class);
  i.putExtra(DiaryDbAdapter.KEY_ROWID, id);
  i.putExtra(DiaryDbAdapter.KEY_TITLE, c.getString(c.getColumnIndexOrThrow(DiaryDbAdapter.KEY_TITLE)));
  i.putExtra(DiaryDbAdapter.KEY_BODY, c.getString(c.getColumnIndexOrThrow(DiaryDbAdapter.KEY_BODY)));
  startActivityForResult(i, ACTIVITY_EDIT);
 }
 @Override
 protected void onActivityResult(int requestCode, int resultCode,
   Intent intent) {
  super.onActivityResult(requestCode, resultCode, intent);
  renderListView();
 }
}

数据库访问接口DiaryDbAdapter.java：
//数据访问接口
public class DiaryDbAdapter {
 public static final String KEY_TITLE = "title";
 public static final String KEY_BODY = "body";
 public static final String KEY_ROWID = "_id";
 public static final String KEY_CREATED = "created";
 private DatabaseHelper mDbHelper;
 private SQLiteDatabase mDb;
 private static final String DATABASE_CREATE = "create table diary (_id integer primary key autoincrement, "
   + "title text not null, body text not null, created text not null);";
 private static final String DATABASE_NAME = "database";
 private static final String DATABASE_TABLE = "diary";
 private static final int DATABASE_VERSION = 1;

 private final Context mCtx;

 private static class DatabaseHelper extends SQLiteOpenHelper {
  DatabaseHelper(Context context) {
   super(context, DATABASE_NAME, null, DATABASE_VERSION);
  }
  //创建数据表diary
  @Override
  public void onCreate(SQLiteDatabase db) {
   db.execSQL(DATABASE_CREATE);
  }
  @Override
  public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
   //如果存在diary 这张表，我们需要先删除，因为在同一个数据库当中不能出现两张同样名字的表。
   db.execSQL("DROP TABLE IF EXISTS diary");
   onCreate(db);
  }
 }
 public DiaryDbAdapter(Context ctx) {
  this.mCtx = ctx;
 }
 //首先得到一个可写的数据库
 public DiaryDbAdapter open() throws SQLException {
  mDbHelper = new DatabaseHelper(mCtx);
  mDb = mDbHelper.getWritableDatabase();
  return this;
 }
 public void closeclose() {
  mDbHelper.close();
 }
 //向数据库中写入记录
 public long createDiary(String title, String body) {
  ContentValues initialValues = new ContentValues();
  initialValues.put(KEY_TITLE, title);
  initialValues.put(KEY_BODY, body);
  Calendar calendar = Calendar.getInstance();
  String created = calendar.get(Calendar.YEAR) + "年"
    + calendar.get(Calendar.MONTH) + "月"
    + calendar.get(Calendar.DAY_OF_MONTH) + "日"
    + calendar.get(Calendar.HOUR_OF_DAY) + "时"
    + calendar.get(Calendar.MINUTE) + "分";
  initialValues.put(KEY_CREATED, created);
  return mDb.insert(DATABASE_TABLE, null, initialValues);
 }
 //删除指定记录
 public boolean deleteDiary(long rowId) {
  return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
 }
 //获取数据库中所有记录，且只包含id、title、body、created四个字段
 public Cursor getAllNotes() {
  return mDb.query(DATABASE_TABLE, new String[] { KEY_ROWID, KEY_TITLE,KEY_BODY, KEY_CREATED }, null, null, null, null, null);
 }
 //获取指定id的记录
 public Cursor getDiary(long rowId) throws SQLException {
  Cursor mCursor =mDb.query(true, DATABASE_TABLE, new String[] { KEY_ROWID, KEY_TITLE,KEY_BODY, KEY_CREATED }, KEY_ROWID + "=" + rowId, null, null,null, null, null);
  if (mCursor != null) {
   mCursor.moveToFirst();
  }
  return mCursor;
 }
 //更新指定id记录的内容
 public boolean updateDiary(long rowId, String title, String body) {
  ContentValues args = new ContentValues();
  args.put(KEY_TITLE, title);
  args.put(KEY_BODY, body);
  Calendar calendar = Calendar.getInstance();
  String created = calendar.get(Calendar.YEAR) + "年"
    + calendar.get(Calendar.MONTH) + "月"
    + calendar.get(Calendar.DAY_OF_MONTH) + "日"
    + calendar.get(Calendar.HOUR_OF_DAY) + "时"
    + calendar.get(Calendar.MINUTE) + "分";
  args.put(KEY_CREATED, created);
  return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
 }
}

编辑日记界面ActivityDiaryEdit.java
//记录编辑界面
public class ActivityDiaryEdit extends Activity {
 private EditText mTitleText;
 private EditText mBodyText;
 private Long mRowId;
 private DiaryDbAdapter mDbHelper;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  mDbHelper = new DiaryDbAdapter(this);
  mDbHelper.open();
  setContentView(R.layout.diary_edit);
  mTitleText = (EditText) findViewById(R.id.title);
  mBodyText = (EditText) findViewById(R.id.body);
  Button confirmButton = (Button) findViewById(R.id.confirm);
  mRowId = null;
  // 每一个intent都会带一个Bundle型的extras数据。
  //从intent中获取传递内容
  Bundle extras = getIntent().getExtras();
  if (extras != null) {
   String title = extras.getString(DiaryDbAdapter.KEY_TITLE);
   String body = extras.getString(DiaryDbAdapter.KEY_BODY);
   mRowId = extras.getLong(DiaryDbAdapter.KEY_ROWID);
   if (title != null) {
    mTitleText.setText(title);
   }
   if (body != null) {
    mBodyText.setText(body);
   }
  }
  //填写完毕后，写入数据库
  confirmButton.setOnClickListener(new View.OnClickListener() {
   public void onClick(View view) {
    String title = mTitleText.getText().toString();
    String body = mBodyText.getText().toString();
    if (mRowId != null) {
     mDbHelper.updateDiary(mRowId, title, body);
    } else
     mDbHelper.createDiary(title, body);
    Intent mIntent = new Intent();
    setResult(RESULT_OK, mIntent);
    finish();
   }
  });
 }
}