Loading a stored json from SharedPreferences

Question

The problem

This issue has been bugging me for quite some time. It is not very common, but it does happen from time to time. The problem is the following:

I save a bunch of user preferences in s Gson serialized object in SharedPreferences. This way, when I need the object I load it to memory doing only 1 call to storage. However, for some bizzare reason I am getting this error:

java.lang.RuntimeException: Unable to resume activity {com.a.b/com.a.b.SomeActivity}: java.lang.RuntimeException: unable to parse type class com.a.b.storage.SomeClass$AppSettings with json: rialFinished":false,"lastOpenedAppId":0,"appVersion":35,"tutorialFinished":false}

As can be observed, the json was not loaded properly, it is an invalid json, so trying to parse it just throws an exception.

Some Additional Facts

• Every single exception thrown shows the exact same json parsing issue. For some reason this is always the string that is being loaded:

rialFinished":false,"lastOpenedAppId":0,"appVersion":35,"tutorialFinished":false}

• This is not a 'device specific issue' or at least I think so. Evidence:
  As you can see, its not specific to a device. I also know for a fact that it is not specific to an android version either, we have this crashed logged from Android 2.3.6, 4.0.3, 4.1.1, 4.1.2, 4.0.4

• The class that is serialized is

  class AppSettings {
  
  private boolean tutorialFinished;
  private boolean googleAuthTutorialFinished;
  private int appVersion;
  private int lastOpenedAppId;
  
  public AppSettings() {
      tutorialFinished = false;
      appVersion = NO_STORED_VERSION;
      googleAuthTutorialFinished = false;
  }
  
  public boolean isTutorialFinished() {
      return tutorialFinished;
  }
  
  public void setTutorialFinished(boolean tutorialFinished) {
      this.tutorialFinished = tutorialFinished;
  }
  
  public void setAppVerions(int appVerions) {
      this.appVersion = appVerions;
  }
  
  public void setGoogleAuthTutorialFinished(boolean googleAuthTutorialFinished) {
      this.googleAuthTutorialFinished = googleAuthTutorialFinished;
  }
  
  /**
   *
   * @return the stored app version or {@link AppSettingsStorage#NO_STORED_VERSION} if none was found
   */
  public int getAppVerions() {
      return appVersion;
  }
  
  public boolean isGoogleAuthTutorialFinished() {
      return googleAuthTutorialFinished;
  }
  
  public int getLastOpenedAppId() {
      return lastOpenedAppId;
  }
  
  public void setLastOpenedAppId(int lastOpenedAppId) {
      this.lastOpenedAppId = lastOpenedAppId;
  }
  
  }
  

• the method used to load the json is:

      private T fromJson(String json) {
              try {
                  return gson.fromJson(json, type);
              } catch (Exception e) {
                  throw new RuntimeException("unable to parse type " + type + " with json: " + json);
              }
          }
  

Possible reasons:

• https://code.google.com/p/android/issues/detail?id=14359. This issue states that some Android devices just don't work well with the SharedPreferences. Although I'm sure that specific issue is not the case here, I wonder if it has something to do.

• Maybe there is some odd process-safety issue at hand here. (Shared Preferences And Thread/Process safety)

• AppSettings is an inner class. Could this affect Gson serialization somehow?

Answer 1

Are you missing a double quote?

unable to parse type class com.a.b.storage.SomeClass$AppSettings with json: 

rialFinished":false,"lastOpenedAppId":0,"appVersion":35,"tutorialFinished":false}

should that be:

unable to parse type class com.a.b.storage.SomeClass$AppSettings with json: 

"rialFinished":false,"lastOpenedAppId":0,"appVersion":35,"tutorialFinished":false}