Question

I have a function in my android application:

public static <T> void saveLocalData(Context context, String key, Class<T> value) {
    // Check type of value here
    SharedPreferences prefs = context.getSharedPreferences(
            Constants.PREFERENCES_KEY, Context.MODE_PRIVATE);
    SharedPreferences.Editor editor = prefs.edit();
    if(value.isAssignableFrom(String.class)){
        //Put value here
    }
    else if(value.isAssignableFrom(Boolean.class)){
        //Put value here            
    }

    editor.commit();
}

I want to check type of value in this function (I want to check two type Boolean and String), but I don’t know how to do it! Can anyone give any suggestion? Thanks!

Edited: Thanks every for help! I have one more problem that is how to save it value to Preferences?

Answer 1

You could use Class.isAssignableFrom().

Determines if the class or interface represented by this Class object
is either the same as, or is a superclass or superinterface of, the
class or interface represented by the specified Class parameter

---

UPDATE: By the edit in the question, and in order to set the key/value in a SharedPreferences.Editor, use putString() and putBoolean().

Take into account you’ll need to receive the value as an argument. Notice that if you receive the value, you can already access its class (so you don’t need Class<T> as an argument nor isAssignableFrom()), and check it by means of the instanceof operator:

public static <T> void saveLocalData(Context context, String key, T value) {
    SharedPreferences prefs = context.getSharedPreferences(
        Constants.PREFERENCES_KEY, Context.MODE_PRIVATE);
    SharedPreferences.Editor editor = prefs.edit();
    if (value instanceof String) { 
        editor.putString(key, (String) value);
    }
    else if (value instanceof Boolean){
        editor.putBoolean(key, (Boolean) value);
    }
    editor.commit();
}