Java SQLiteOpenHelper类代码示例

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
public SQLiteDatabaseWrapper borrowObject() throws Exception {

        synchronized (pool) {
            if (!initialized) {
                for (int i = 0; i < connections; i++) {

                    // Initialize!
                    SQLiteOpenHelper outerSqLiteOpenHelper;
                    if(dbName == null)
                         outerSqLiteOpenHelper = createSQLiteOpenHelperInstance();
                    else
                        outerSqLiteOpenHelper = createSQLiteOpenHelperInstance(dbName);

                    pool.add(new SQLiteDatabaseWrapper(outerSqLiteOpenHelper));
                }
                initialized = true;
            }

            // wait until there is an available connection
            while (pool.size() == 0) {
                pool.wait();
            }

            return pool.remove(0);
        }
    }
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
public List<HistoryItem> buildHistoryItems() {
  SQLiteOpenHelper helper = new DBHelper(activity);
  List<HistoryItem> items = new ArrayList<>();
  SQLiteDatabase db = null;
  Cursor cursor = null;
  try {
    db = helper.getReadableDatabase();
    cursor = db.query(DBHelper.TABLE_NAME, COLUMNS, null, null, null, null, DBHelper.TIMESTAMP_COL + " DESC");
    while (cursor.moveToNext()) {
      String text = cursor.getString(0);
      String display = cursor.getString(1);
      String format = cursor.getString(2);
      long timestamp = cursor.getLong(3);
      String details = cursor.getString(4);
      Result result = new Result(text, null, null, BarcodeFormat.valueOf(format), timestamp);
      items.add(new HistoryItem(result, display, details));
    }
  } finally {
    close(cursor, db);
  }
  return items;
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
public HistoryItem buildHistoryItem(int number) {
  SQLiteOpenHelper helper = new DBHelper(activity);
  SQLiteDatabase db = null;
  Cursor cursor = null;
  try {
    db = helper.getReadableDatabase();
    cursor = db.query(DBHelper.TABLE_NAME, COLUMNS, null, null, null, null, DBHelper.TIMESTAMP_COL + " DESC");
    cursor.move(number + 1);
    String text = cursor.getString(0);
    String display = cursor.getString(1);
    String format = cursor.getString(2);
    long timestamp = cursor.getLong(3);
    String details = cursor.getString(4);
    Result result = new Result(text, null, null, BarcodeFormat.valueOf(format), timestamp);
    return new HistoryItem(result, display, details);
  } finally {
    close(cursor, db);
  }
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
public void deleteHistoryItem(int number) {
  SQLiteOpenHelper helper = new DBHelper(activity);
  SQLiteDatabase db = null;
  Cursor cursor = null;
  try {
    db = helper.getWritableDatabase();      
    cursor = db.query(DBHelper.TABLE_NAME,
                      ID_COL_PROJECTION,
                      null, null, null, null,
                      DBHelper.TIMESTAMP_COL + " DESC");
    cursor.move(number + 1);
    db.delete(DBHelper.TABLE_NAME, DBHelper.ID_COL + '=' + cursor.getString(0), null);
  } finally {
    close(cursor, db);
  }
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
public void trimHistory() {
  SQLiteOpenHelper helper = new DBHelper(activity);
  SQLiteDatabase db = null;
  Cursor cursor = null;
  try {
    db = helper.getWritableDatabase();      
    cursor = db.query(DBHelper.TABLE_NAME,
                      ID_COL_PROJECTION,
                      null, null, null, null,
                      DBHelper.TIMESTAMP_COL + " DESC");
    cursor.move(MAX_ITEMS);
    while (cursor.moveToNext()) {
      String id = cursor.getString(0);
      Log.i(TAG, "Deleting scan history ID " + id);
      db.delete(DBHelper.TABLE_NAME, DBHelper.ID_COL + '=' + id, null);
    }
  } catch (SQLiteException sqle) {
    // We're seeing an error here when called in CaptureActivity.onCreate() in rare cases
    // and don't understand it. First theory is that it's transient so can be safely ignored.
    Log.w(TAG, sqle);
    // continue
  } finally {
    close(cursor, db);
  }
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
/**
 * Upgrade existing database.
 */
@Test
public void sequentialUpgrade() {
    final Context ctx = RuntimeEnvironment.application.getApplicationContext();
    final int[] versions = new int[]{1, 2, 3};
    for (int i = 1; i <= 3; i++) {
        final SQLiteOpenHelper unit = new DBUnit(ctx, i);
        final SQLiteDatabase db = unit.getReadableDatabase();
        Cursor cursor = null;
        try {
            cursor = db.rawQuery("SELECT value FROM versions", new String[0]);
            assertVersions(cursor, Arrays.copyOf(versions, i));
        } finally {
            if (cursor != null) {
                cursor.close();
            }
            db.close();
        }
        unit.close();
    }
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
/**
 * Apply migrations from custom folder.
 */
@Test
public void customFolder() {
    final Context ctx = RuntimeEnvironment.application;

    final SQLiteOpenHelper unit = new DBUnit(ctx, 1, "custom_migrations");
    final SQLiteDatabase database = unit.getReadableDatabase();
    Cursor cursor = null;
    try {
        cursor = database.rawQuery("SELECT value FROM custom_versions", new String[0]);
        assertVersions(cursor, 1);
    } finally {
        if (cursor != null) {
            cursor.close();
        }
        database.close();
    }
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
@Provides
@Singleton
BriteDatabase provideDatabase(SqlBrite sqlBrite, SQLiteOpenHelper helper) {
    BriteDatabase db = sqlBrite.wrapDatabaseHelper(helper, Schedulers.io());
    db.setLoggingEnabled(true);
    return db;
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
protected SQLiteOpenHelper createSQLiteOpenHelperInstance() throws Exception {
    // We want the constructor with Context parameter
    Constructor<?> cons = sqliteOpenHelperClass.getConstructor(new Class[] { Context.class });

    // We create the instance!
    return (SQLiteOpenHelper) cons.newInstance(context);
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
@Override
public boolean onCreate()
{
	try
	{
		SQLiteOpenHelper databaseHelper = new Database(getContext(), DATABASE_NAME, null, DATABASE_VERSION);
		database = databaseHelper.getWritableDatabase();
		return (database != null) ? true : false;
	}
	catch (Exception e)
	{
		Log.e("DatabaseProvider", "onCreate : " + e);
		return false;
	}
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
public boolean hasHistoryItems() {
  SQLiteOpenHelper helper = new DBHelper(activity);
  SQLiteDatabase db = null;
  Cursor cursor = null;
  try {
    db = helper.getReadableDatabase();
    cursor = db.query(DBHelper.TABLE_NAME, COUNT_COLUMN, null, null, null, null, null);
    cursor.moveToFirst();
    return cursor.getInt(0) > 0;
  } finally {
    close(cursor, db);
  }
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
public void addHistoryItem(Result result, ResultHandler handler) {
  // Do not save this item to the history if the preference is turned off, or the contents are
  // considered secure.
  if (!activity.getIntent().getBooleanExtra(Intents.Scan.SAVE_HISTORY, true) ||
      handler.areContentsSecure() || !enableHistory) {
    return;
  }

  SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(activity);
  if (!prefs.getBoolean(PreferencesActivity.KEY_REMEMBER_DUPLICATES, false)) {
    deletePrevious(result.getText());
  }

  ContentValues values = new ContentValues();
  values.put(DBHelper.TEXT_COL, result.getText());
  values.put(DBHelper.FORMAT_COL, result.getBarcodeFormat().toString());
  values.put(DBHelper.DISPLAY_COL, handler.getDisplayContents().toString());
  values.put(DBHelper.TIMESTAMP_COL, System.currentTimeMillis());

  SQLiteOpenHelper helper = new DBHelper(activity);
  SQLiteDatabase db = null;
  try {
    db = helper.getWritableDatabase();      
    // Insert the new entry into the DB.
    db.insert(DBHelper.TABLE_NAME, DBHelper.TIMESTAMP_COL, values);
  } finally {
    close(null, db);
  }
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
private void deletePrevious(String text) {
  SQLiteOpenHelper helper = new DBHelper(activity);
  SQLiteDatabase db = null;
  try {
    db = helper.getWritableDatabase();      
    db.delete(DBHelper.TABLE_NAME, DBHelper.TEXT_COL + "=?", new String[] { text });
  } finally {
    close(null, db);
  }
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
/**
 * <p>Builds a text representation of the scanning history. Each scan is encoded on one
 * line, terminated by a line break (\r\n). The values in each line are comma-separated,
 * and double-quoted. Double-quotes within values are escaped with a sequence of two
 * double-quotes. The fields output are:</p>
 *
 * <ol>
 *  <li>Raw text</li>
 *  <li>Display text</li>
 *  <li>Format (e.g. QR_CODE)</li>
 *  <li>Unix timestamp (milliseconds since the epoch)</li>
 *  <li>Formatted version of timestamp</li>
 *  <li>Supplemental info (e.g. price info for a product barcode)</li>
 * </ol>
 */
CharSequence buildHistory() {
  SQLiteOpenHelper helper = new DBHelper(activity);
  SQLiteDatabase db = null;
  Cursor cursor = null;
  try {
    db = helper.getWritableDatabase();
    cursor = db.query(DBHelper.TABLE_NAME,
                      COLUMNS,
                      null, null, null, null,
                      DBHelper.TIMESTAMP_COL + " DESC");

    DateFormat format = DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.MEDIUM);
    StringBuilder historyText = new StringBuilder(1000);
    while (cursor.moveToNext()) {

      historyText.append('"').append(massageHistoryField(cursor.getString(0))).append("\",");
      historyText.append('"').append(massageHistoryField(cursor.getString(1))).append("\",");
      historyText.append('"').append(massageHistoryField(cursor.getString(2))).append("\",");
      historyText.append('"').append(massageHistoryField(cursor.getString(3))).append("\",");

      // Add timestamp again, formatted
      long timestamp = cursor.getLong(3);
      historyText.append('"').append(massageHistoryField(
          format.format(new Date(timestamp)))).append("\",");

      // Above we're preserving the old ordering of columns which had formatted data in position 5

      historyText.append('"').append(massageHistoryField(cursor.getString(4))).append("\"\r\n");
    }
    return historyText;
  } finally {
    close(cursor, db);
  }
}
 

import android.database.sqlite.SQLiteOpenHelper; //导入依赖的package包/类
void clearHistory() {
  SQLiteOpenHelper helper = new DBHelper(activity);
  SQLiteDatabase db = null;
  try {
    db = helper.getWritableDatabase();      
    db.delete(DBHelper.TABLE_NAME, null, null);
  } finally {
    close(null, db);
  }
}