java - unhandled exception org.json.jsonexception

Question

I'm working on an android app, and the app must save a java object in json format into the SQLite database. I wrote the code for this operation, then they must extract the Json object and reconvert it into a Java Object. When I try to call the method for deserializing the json object in to a string, I found this error in Android Studio:unhandled exception org.json.jsonexception

When I try to catch JSONException e the program runs but don't deserialize the json object.

This is the code for the method:

private void read() throws JSONException {
    SQLiteDatabase db = mMioDbHelper.getWritableDatabase();
    String[] columns = {"StringaAll"};
    Cursor c = db.query("Alle", columns, null, null, null, null,null );
    while(c.moveToNext()) {
        String stringaRis =  c.getString(0);
        JSONObject jObj = new JSONObject(stringaRis);
        String sPassoMed = jObj.getString("passoMed");
        final TextView tView = (TextView) this.findViewById(R.id.mainProvaQuery);
        tView.setText(sPassoMed);
        // }
    }
}

Can you help me please?

Answer 1

Yes, you need to catch the exception.

But when you catch it, you should not just throw it on the floor. Your application needs to do something about the exception. Or if you / it is not expecting an exception to occur at runtime, then at least you should report it. Here's a minimal example (for an Android app)

try {
    ...
    JSONObject jObj = new JSONObject(stringaRis);
    ...
} catch (JSONException e) {
    Log.e("MYAPP", "unexpected JSON exception", e);
    // Do something to recover ... or kill the app.
}

Of course, this does not solve your problem. The next thing you need to do is to figure out why you are getting the exception. Start by reading the exception message that you have logged to logcat.

---

Re this exception message:

org.json.JSONException: Value A of type java.lang.String cannot be converted to JSONObject

I assume it is thrown by this line:

    JSONObject jObj = new JSONObject(stringaRis);

I think that it is telling you is that stringaRis has the value "A" ... and that cannot be parsed as a JSON object. It isn't JSON at all.