android.database.sqlite.SQLiteDatabase#enableWriteAheadLogging ( )源码实例Demo

/**
 * 获取数据库连接
 */
SQLiteDatabase getDb() {
  SQLiteDatabase db;
  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
    SQLiteDatabase.OpenParams params = new SQLiteDatabase.OpenParams.Builder().setOpenFlags(
        SQLiteDatabase.NO_LOCALIZED_COLLATORS | SQLiteDatabase.OPEN_READWRITE |
            SQLiteDatabase.CREATE_IF_NECESSARY).build();
    setOpenParams(params);
    db = getWritableDatabase();
  } else {
    //SQLiteDatabase.openOrCreateDatabase()
    File dbFile = mContext.getDatabasePath(DBConfig.DB_NAME);
    if (!dbFile.exists()) {
      db = getWritableDatabase();
    } else {
      // 触发一次SQLiteOpenHelper的流程，再使用NO_LOCALIZED_COLLATORS标志打开数据库
      db = getReadableDatabase();
      db.close();
      db = SQLiteDatabase.openDatabase(dbFile.getPath(), null,
          SQLiteDatabase.NO_LOCALIZED_COLLATORS | SQLiteDatabase.OPEN_READWRITE |
              SQLiteDatabase.CREATE_IF_NECESSARY);
    }
  }
  db.enableWriteAheadLogging();
  return db;
}
 

@Override public void onOpen(SQLiteDatabase db) {
    super.onOpen(db);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
        setWriteAheadLoggingEnabled(true);
    } else {
        db.enableWriteAheadLogging();
    }
}
 

/**
 * Creates a new instance of the simple open helper.
 *
 * @param context Context to read assets. This will be helped by the
 *                instance.
 */
private DevicesOpenHelper(Context context) {
    super(context, DB_NAME, null, SCHEMA_VERSION);

    this.context = context;

    // This will happen in onConfigure for API >= 16
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
        SQLiteDatabase db = getWritableDatabase();
        db.enableWriteAheadLogging();
        db.execSQL("PRAGMA foreign_keys = ON;");
    }
}
 

@Override
public void enableFeatures(@SQLiteOpenOptions int openOptions, SQLiteDatabase db) {
  if ((openOptions & ENABLE_WRITE_AHEAD_LOGGING) != 0) {
    db.enableWriteAheadLogging();
  }

  if ((openOptions & ENABLE_FOREIGN_KEY_CONSTRAINTS) != 0) {
    db.execSQL("PRAGMA foreign_keys = ON");
  }
}
 

@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
@Override
public void onConfigure(SQLiteDatabase db) {
    super.onConfigure(db);
    if (!db.isReadOnly()) {
        db.enableWriteAheadLogging();
    }
}
 

@Override
public void onOpen(SQLiteDatabase db) {
    super.onOpen(db);
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN && Build.VERSION.SDK_INT > Build.VERSION_CODES.HONEYCOMB) {
        db.enableWriteAheadLogging();
    }
}
 

@Override
public void onOpen(SQLiteDatabase db) {
    super.onOpen(db);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
        setWriteAheadLoggingEnabled(true);
    } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
        db.enableWriteAheadLogging();
    }
}
 

@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
@Override
public void onConfigure(SQLiteDatabase db) {

    super.onConfigure(db);
    if (!db.isReadOnly()) {
        db.enableWriteAheadLogging();
    }
}
 

public void createSampleData() {
    MyDatabaseHelper helper = new MyDatabaseHelper(this);
    SQLiteDatabase db = helper.getWritableDatabase();
    long start = 0;
    try {
        // WALを有効にする
        db.enableWriteAheadLogging();
        Log.d(TAG, "WAL :" + db.isWriteAheadLoggingEnabled());
        db.beginTransaction();
        start = System.nanoTime();
        for (int i = 0; i < 10000; i++) {
            String name = NAMES[mRand.nextInt(NAMES.length)];
            int age = mRand.nextInt(80);
            ContentValues values = new ContentValues();
            values.put("NAME", name);
            values.put("AGE", age);
            db.insert("USERS", null, values);
        }
        start = printTimeLog("Insert処理", start, System.nanoTime());
        db.setTransactionSuccessful();
        start = printTimeLog("setTransactionSuccessful", start,
                System.nanoTime());
    } finally {
        db.endTransaction();
        start = printTimeLog("endTransaction", start, System.nanoTime());
        db.close();
        helper.close();
        printTimeLog("Close処理", start, System.nanoTime());
    }
}
 

@Override
public void onConfigure(SQLiteDatabase db) {
    db.enableWriteAheadLogging();
    super.onConfigure(db);
}
 

@Override
public void onOpen(SQLiteDatabase db) {
    super.onOpen(db);
    QiscusLogger.print("Opening database.. ");
    db.enableWriteAheadLogging();
}
 

@Override
public void onConfigure(SQLiteDatabase db) {
    db.enableWriteAheadLogging();
    super.onConfigure(db);
}
 

@Override
public SQLiteDatabase getReadableDatabase() {
    SQLiteDatabase database = super.getReadableDatabase();
    database.enableWriteAheadLogging();
    return database;
}
 

@Override
public SQLiteDatabase getWritableDatabase() {
    SQLiteDatabase database = super.getWritableDatabase();
    database.enableWriteAheadLogging();
    return database;
}
 

@Override
public SQLiteDatabase getReadableDatabase() {
    SQLiteDatabase db = super.getReadableDatabase();
    db.enableWriteAheadLogging();
    return db;
}
 

@Override
public SQLiteDatabase getWritableDatabase() {
    SQLiteDatabase db = super.getWritableDatabase();
    db.enableWriteAheadLogging();
    return db;
}
 

@Provides @Singleton SQLiteDatabase provideDb() {
    DatabaseHelper databaseHelper = new DatabaseHelper(context);
    SQLiteDatabase db = databaseHelper.getWritableDatabase();
    db.enableWriteAheadLogging();
    return db;
}
 

@Provides @Singleton SQLiteDatabase provideDb() {
    DatabaseHelper databaseHelper = new DatabaseHelper(context);
    SQLiteDatabase db = databaseHelper.getWritableDatabase();
    db.enableWriteAheadLogging();
    return db;
}
 

@Override
public void onOpen(SQLiteDatabase db) {

    super.onOpen(db);

    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN && Build.VERSION.SDK_INT > Build.VERSION_CODES.HONEYCOMB) {

        db.enableWriteAheadLogging();
    }
}