导出和导入所有SharedPreferences到一个文件

Question

在我的Android应用我有不同的类型有两种SharedPreference文件中的数据（布尔，数字和字符串）：com.package.index和com.package.storage。 的问题是，它怎么可能完全位于SharedPreference文件导出到外部文件并导入回来？ （这对于设备之间的备份和迁移至关重要），谢谢

Answer 1

这是我做的：

private final SharedPreferences _settings; 
/** 
* Serialize all preferences into an output stream 
* @param os OutputStream to write to 
* @return True iff successful 
*/ 
public boolean serialize(final @NonNull OutputStream os) { 
    ObjectOutputStream oos = null; 
    try { 
     oos = new ObjectOutputStream(os); 
     oos.writeObject(_settings.getAll()); 
     oos.close(); 
    } catch (IOException e) { 
     Log.e(TAG, "Error serializing preferences", BuildConfig.DEBUG ? e : null); 
     return false; 
    } finally { 
     Utils.closeQuietly(oos, os); 
    } 
    return true; 
} 

/** 
* Read all preferences from an input stream. 
* Schedules a full preference clean, then deserializes the options present in the given stream. 
* If the given object contains an unknown class, the deserialization is aborted and the underlying 
* preferences are not changed by this method 
* @param is Input stream to load the preferences from 
* @return True iff the new values were successfully written to persistent storage 
* 
* @throws IllegalArgumentException 
*/ 
public boolean deserialize(final @NonNull InputStream is) { 
    ObjectInputStream ois = null; 
    Map<String, Object> map = null; 
    try { 
     ois = new ObjectInputStream(is); 
     map = (Map) ois.readObject(); 
    } catch (IOException | ClassNotFoundException e) { 
     Log.e(TAG, "Error deserializing preferences", BuildConfig.DEBUG ? e : null); 
     return false; 
    } finally { 
     Utils.closeQuietly(ois, is); 
    } 

    SharedPreferences.Editor editor = _settings.edit(); 
    editor.clear(); 

    for (Map.Entry<String, Object> e : map.entrySet()) { 
     // Unfortunately, the editor only provides typed setters 
     if (e.getValue() instanceof Boolean) { 
      editor.putBoolean(e.getKey(), (Boolean)e.getValue()); 
     } else if (e.getValue() instanceof String) { 
      editor.putString(e.getKey(), (String)e.getValue()); 
     } else if (e.getValue() instanceof Integer) { 
      editor.putInt(e.getKey(), (int)e.getValue()); 
     } else if (e.getValue() instanceof Float) { 
      editor.putFloat(e.getKey(), (float)e.getValue()); 
     } else if (e.getValue() instanceof Long) { 
      editor.putLong(e.getKey(), (Long) e.getValue()); 
     } else if (e.getValue() instanceof Set) { 
      editor.putStringSet(e.getKey(), (Set<String>) e.getValue()); 
     } else { 
      throw new IllegalArgumentException("Type " + e.getValue().getClass().getName() + " is unknown"); 
     } 
    } 
    return editor.commit(); 
} 

Answer 2

SharedPreferences有一个getAll()方法，您可以使用该方法检索给定SharedPreferences中的所有值。然后，您可以使用自己的喜好进行序列化在外部文件中的值。

注意，在Android 6.0（API 23）以上，Auto Backup for Apps将自动备份共享偏好为你的文件。