<<SQLiteDemo2.zip>>

SQLite Demo 2

本演練演示一個日記本程序

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• 新建項目SQLiteDemo2, 編輯res/layout/main.xml 文件

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  <?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="沒有日記內容點擊菜單開始寫日記" />

  </LinearLayout>

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  2. 在res/layout/ 新建布局文件 diary_row.xml 用于顯示日記的界面：

  <?xml version="1.0" encoding="utf-8"?>

  <RelativeLayout android:id="@+id/row"

  xmlns:android="http://schemas.android.com/apk/res/android"

  android:layout_width="fill_parent"

  android:layout_height="fill_parent">

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  <TextView android:id="@+id/text1"

  android:layout_width="wrap_content" android:layout_height="30px"

  android:maxWidth="200dip"

  android:textSize="22sp"

  android:layout_marginTop="10dip"

  android:text="標題" />

  <TextView android:id="@+id/created" android:layout_width="wrap_content"

  android:layout_height="35px" android:layout_alignParentRight="true"

  android:layout_marginLeft="10dip"

  android:layout_marginTop="10dip"

  android:text="xxxx年xx月xx日" />

  </RelativeLayout>

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  3. 在res/layout/新建布局文件 diary_edit.xml 用于編輯日記的界面

  <?xml version="1.0" encoding="utf-8"?>

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  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

  android:orientation="vertical" android:layout_width="fill_parent"

  android:layout_height="fill_parent">

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  <LinearLayout android:orientation="vertical"

  android:layout_width="fill_parent"

  android:layout_height="wrap_content">

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  <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>

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  <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" />

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  <Button android:id="@+id/confirm" android:text="@string/confirm"

  android:layout_width="wrap_content"

  android:layout_height="wrap_content" />

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  </LinearLayout>

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  4. 打開res/values/string.xml，添加如下內容：

  <?xml version="1.0" encoding="utf-8"?>

  <resources>

  <string name="hello">Hello World, SQLiteDemo2!</string>

  <string name="app_name">SQLiteDemo2</string>

  <string name="menu_insert">添加一篇新日記</string>

  <string name="menu_delete">刪除一篇日記</string>

  <string name="title">標題</string>

  <string name="body">內容</string>

  <string name="confirm">確定</string>

  <string name="edit_diary">編輯日記</string>

  </resources>

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  5. 新建DiaryDbAdapter類，用于封裝對數據庫的操作。

  import java.util.Calendar;

  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;

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  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";

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  private static final String TAG = "DiaryDbAdapter";

  private DatabaseHelper mDbHelper;

  private SQLiteDatabase mDb;

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  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);";

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  private static final String DATABASE_NAME = "database";

  private static final String DATABASE_TABLE = "diary";

  private static final int DATABASE_VERSION = 1;

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  private final Context mCtx;

  private static class DatabaseHelper extends SQLiteOpenHelper {

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  DatabaseHelper(Context context) {

  super(context, DATABASE_NAME, null, DATABASE_VERSION);

  }

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  @Override

  public void onCreate(SQLiteDatabase db) {

  db.execSQL(DATABASE_CREATE);

  }

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  @Override

  public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

  db.execSQL("DROP TABLE IF EXISTS diary");

  onCreate(db);

  }

  }

  public DiaryDbAdapter(Context ctx) {

  this.mCtx = ctx;

  }

  public DiaryDbAdapter open() throws SQLException {

  mDbHelper = new DatabaseHelper(mCtx);

  mDb = mDbHelper.getWritableDatabase();

  return this;

  }

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  public void closeclose() {

  mDbHelper.close();

  }

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  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) + "時"

  + calendar.get(Calendar.MINUTE) + "分";

  initialValues.put(KEY_CREATED, created);

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

  }

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  public boolean deleteDiary(long rowId) {

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

  }

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  public Cursor getAllNotes() {

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  return mDb.query(DATABASE_TABLE, new String[] { KEY_ROWID, KEY_TITLE,

  KEY_BODY, KEY_CREATED }, null, null, null, null, null);

  }

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  public Cursor getDiary(long rowId) throws SQLException {

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  Cursor mCursor =

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  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;

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  }

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  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) + "時"

  + calendar.get(Calendar.MINUTE) + "分";

  args.put(KEY_CREATED, created);

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

  }

  }

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  6. 新建類DiaryEditActivity類繼承自Activity類用于編輯日記:

  import android.app.Activity;

  import android.content.Intent;

  import android.os.Bundle;

  import android.view.View;

  import android.widget.Button;

  import android.widget.EditText;

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  public class DiaryEditActivity extends Activity {

  private EditText mTitleText;

  private EditText mBodyText;

  private Long mRowId;

  private DiaryDbAdapter mDbHelper;

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  @Override

  protected void onCreate(Bundle savedInstanceState) {

  super.onCreate(savedInstanceState);

  mDbHelper = new DiaryDbAdapter(this);

  mDbHelper.open();

  setContentView(R.layout.diary_edit);

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  mTitleText = (EditText) findViewById(R.id.title);

  mBodyText = (EditText) findViewById(R.id.body);

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  Button confirmButton = (Button) findViewById(R.id.confirm);

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  mRowId = null;

  // 每一個intent都會帶一個Bundle型的extras數據。

  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);

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  if (title != null) {

  mTitleText.setText(title);

  }

  if (body != null) {

  mBodyText.setText(body);

  }

  }

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  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();

  }

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  });

  }

  }

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  7. 編輯SQLiteDemo2類

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  import android.app.Activity;

  import android.app.ListActivity;

  import android.content.Intent;

  import android.database.Cursor;

  import android.os.Bundle;

  import android.view.Menu;

  import android.view.MenuItem;

  import android.view.View;

  import android.widget.ListView;

  import android.widget.SimpleCursorAdapter;

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  public class SQLiteDemo2 extends ListActivity {

  private static final int ACTIVITY_CREATE = 0;

  private static final int ACTIVITY_EDIT = 1;

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  private static final int INSERT_ID = Menu.FIRST;

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

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  private DiaryDbAdapter mDbHelper;

  private Cursor mDiaryCursor;

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  @Override

  public void onCreate(Bundle savedInstanceState) {

  super.onCreate(savedInstanceState);

  setContentView(R.layout.main);

  mDbHelper = new DiaryDbAdapter(this);

  mDbHelper.open();

  renderListView();

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  }

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  private void renderListView() {

  mDiaryCursor = mDbHelper.getAllNotes();

  startManagingCursor(mDiaryCursor);

  String[] from = new String[] { DiaryDbAdapter.KEY_TITLE,

  DiaryDbAdapter.KEY_CREATED };

  int[] to = new int[] { R.id.text1, R.id.created };

  SimpleCursorAdapter notes = new SimpleCursorAdapter(this,

  R.layout.diary_row, mDiaryCursor, from, to);

  setListAdapter(notes);

  }

  @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;

  }

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  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);

  }

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  private void createDiary() {

  Intent i = new Intent(this, DiaryEditActivity.class);

  startActivityForResult(i, ACTIVITY_CREATE);

  }

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  protected void onListItemClick(ListView l, View v, int position, long id) {

  super.onListItemClick(l, v, position, id);

  Cursor c = mDiaryCursor;

  c.moveToPosition(position);

  Intent i = new Intent(this, DiaryEditActivity.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);

  }

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  @Override

  protected void onActivityResult(int requestCode, int resultCode,

  Intent intent) {

  super.onActivityResult(requestCode, resultCode, intent);

  renderListView();

  }

  }

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  8. 在AndroidManifest.xml 中配置

  <activity android:name="DiaryEditActivity"></activity>

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轉載于:https://www.cnblogs.com/xingquan/archive/2011/03/25/1995718.html

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