页: 1 闪电是正确的,你应当删除旧的b布,复制新的b。

假设您使用<代码>SQLiteOpenHelper,您可使用<代码>createDatabaseIfRequired();、getReadableDatabase(和getWritableDatabase()。

private boolean checkOldDatabase() {
    Log.d(Constants.LOGTAG, "OperationDbHelper.checkDatabase");
    File f = new File(DB_PATH + OLD_DB_NAME);
    return f.exists();
}

public void createDatabaseIfRequired() throws IOException, SQLiteException {
    if (!checkOldDatabase()) {
      // do db comparison / delete old db / copy new db
    }
}

Just rename the File. Make sure the database is closed first!

在你的活动类别中呼吁这样做:

private void renameDatabase()
{
    File databaseFile = getDatabasePath("yourdb.whatever");
    File oldDatabaseFile = new File(databaseFile.getParentFile(), "yourdb_old.whatever");

    databaseFile.renameTo(oldDatabaseFile);
}

对澄清的答复。 重新命名旧(如上所述),从资产夹中复制新资产,开放数据库,进行比较。 然后删除旧档案。

不可能直接改用一张薄片。

但是,你可以复制这一文件,创造新的和删除旧的。

Thanks to Kevin Galligan s answer, I was able to create a function in my Kotlin Android app that I can use whenever it might ever be necessary, to rename the database files.

如果你重新使用 Java,你就不得不把yn改成比,但希望这部法典能够有所解释。

val x: String = "Hello"
//in Kotlin would be
String x = "Hello";
//in Java, for example.

不管怎么说,在我的法典中,我感到可以自由地问问:你有:

private fun checkAndRenameDatabase(oldName: String, newName: String) {
    val oldDatabaseFile: File = getDatabasePath(oldName)
    val oldDatabaseJournal: File = getDatabasePath("${oldName}-journal")

    // Can use this to check files beforehand, using breakpoints 
    //val files = oldDatabaseFile.parentFile.listFiles()

    if(oldDatabaseFile.exists() || oldDatabaseJournal.exists()) {
        db.close()  // Ensure existing database is closed

        val newDatabaseFile: File = getDatabasePath(newName)
        val newDatabaseJournal: File = getDatabasePath("${newName}-journal")

        if(oldDatabaseFile.exists()) {
            if(newDatabaseFile.exists()) {
                newDatabaseFile.delete()
            }
            oldDatabaseFile.renameTo(newDatabaseFile)
        }

        if(oldDatabaseJournal.exists()) {
            if(newDatabaseJournal.exists()) {
                newDatabaseJournal.delete()
            }
            oldDatabaseJournal.renameTo(newDatabaseJournal)
        }

        // Use with breakpoints to ensure files are now in order
        //val newFiles = oldDatabaseFile.parentFile.listFiles()

        // Re-open database with new name
        db = SQLiteDBHelper(applicationContext, newName)
    }
}