領域配置管理

Question

我使用Realm與我的android項目。目前，我定義默認領域配置在我的應用程序類如下 -

@Override 
public void onCreate(){ 
    super.onCreate(); 
    myApplication=this; 
    RealmConfiguration realmConfiguration = new RealmConfiguration.Builder(this).deleteRealmIfMigrationNeeded().build(); 
    Realm.setDefaultConfiguration(realmConfiguration); 
    Thread.setDefaultUncaughtExceptionHandler(new UnhandledExceptionHandler()); 

} 

在當前情況下只有1個用戶使用設備。她使用她的憑據登錄到應用程序並使用默認領域配置。

但是，有了新的要求，同一個android設備可以被不同的用戶使用，因此我需要每個用戶有不同的領域配置，這樣每個用戶都有自己的領域文件嗎？

如果這是真的，那麼管理領域配置的最好方法是什麼？我應該在登錄活動中這樣做嗎？我應該在登錄活動中爲每個用戶創建不同的領域配置嗎？

感謝

Apurva

Answer 1

IMO，使用工廠類將是有益的，因爲你管理多個領域實例。它可能看起來像這樣，

public class RealmFactory { 
/* Realm 
* CAUTION: Be careful which thread you call this from, it is not Thread safe */ 
public static Realm getRealmInstance(Context context, String primaryKeyFromUser) { 
    return Realm.getInstance(getRealmConfiguration(context, primaryKeyFromUser)); 
} 

/* RealmConfiguration */ 
private static RealmConfiguration getRealmConfiguration(Context context, String primaryKeyFromUser) { 
    return new RealmConfiguration.Builder(context) 
      .name(primaryKeyFromUser) 
      .encryptionKey(getSecurityKey()) 
      .deleteRealmIfMigrationNeeded() 
      .build(); 
} 

/* SecurityKey, 
* CAUTION: This is just a sample */ 
private static byte[] getSecurityKey() { 
    char[] chars = "16CharacterLongPasswordKey4Realm".toCharArray(); 
    byte[] key = new byte[chars.length * 2]; 
    for (int i = 0; i < chars.length; i++) { 
     key[i * 2] = (byte) (chars[i] >> 8); 
     key[i * 2 + 1] = (byte) chars[i]; 
    } 

    return key; 
} 

/* Check for Realm file */ 
public static boolean isRealmFileExists(Context context, String primaryKeyFromUser) { 
    RealmConfiguration realmConfiguration = new RealmConfiguration.Builder(context) 
      .name(primaryKeyFromUser) 
      .encryptionKey(getSecurityKey()) 
      .deleteRealmIfMigrationNeeded() 
      .build(); 

    File realmFile = new File(realmConfiguration.getPath()); 
    return realmFile.exists(); 
} 

/* Delete Realm file, if exists 
* CAUTION: if the Realm instance with given configuration is open, make sure you close it 
*   first, before deleting it, else an Exception will be thrown. */ 
public static void deleteRealmFile(Context context, String primaryKeyFromUser) { 
    RealmConfiguration realmConfiguration = new RealmConfiguration.Builder(context) 
      .name(primaryKeyFromUser) 
      .build(); 
    Realm.deleteRealm(realmConfiguration); 
} 

/* Delete all Realm files, if exists 
* CAUTION: if the Realm instance with given configuration is open, make sure you close it 
*   first, before deleting it, else an Exception will be thrown. */ 
public static void deleteAllRealmFiles(Context context) { 
    File file = new File(context.getFilesDir().getPath()); 

    File list[] = file.listFiles(new FileFilter() { 
     @Override 
     public boolean accept(File pathname) { 
      return pathname.isFile(); 
     } 
    }); 

    for (File deleteFile : list) { 
     RealmConfiguration realmConfiguration = new RealmConfiguration.Builder(context) 
       .name(deleteFile.getName()) 
       .build(); 
     Realm.deleteRealm(realmConfiguration); 
    } 
} 
}