Gson - convert from Json to a typed ArrayList<T>
You may use TypeToken to load the json string into a custom object.
logs = gson.fromJson(br, new TypeToken<List<JsonLog>>(){}.getType());
Documentation:
Represents a generic type T.
Java doesn't yet provide a way to represent generic types, so this class does. Forces clients to create a subclass of this class which enables retrieval the type information even at runtime.
For example, to create a type literal for
List<String>
, you can create an empty anonymous inner class:
TypeToken<List<String>> list = new TypeToken<List<String>>() {};
This syntax cannot be used to create type literals that have wildcard parameters, such as
Class<?>
orList<? extends CharSequence>
.
Kotlin:
If you need to do it in Kotlin you can do it like this:
val myType = object : TypeToken<List<JsonLong>>() {}.type
val logs = gson.fromJson<List<JsonLong>>(br, myType)
Or you can see this answer for various alternatives.
Your JSON sample is:
{
"status": "ok",
"comment": "",
"result": {
"id": 276,
"firstName": "mohamed",
"lastName": "hussien",
"players": [
"player 1",
"player 2",
"player 3",
"player 4",
"player 5"
]
}
so if you want to save arraylist of modules in your SharedPrefrences so :
1- will convert your returned arraylist for json format using this method
public static String toJson(Object jsonObject) {
return new Gson().toJson(jsonObject);
}
2- Save it in shared prefreneces
PreferencesUtils.getInstance(context).setString("players", toJson((.....ArrayList you want to convert.....)));
3- to retrieve it at any time get JsonString from Shared preferences like that
String playersString= PreferencesUtils.getInstance(this).getString("players");
4- convert it again to array list
public static Object fromJson(String jsonString, Type type) {
return new Gson().fromJson(jsonString, type);
}
ArrayList<String> playersList= (ArrayList<String>) fromJson(playersString,
new TypeToken<ArrayList<String>>() {
}.getType());
this solution also doable if you want to parse ArrayList of Objects Hope it's help you by using Gson Library .
If you want to use Arrays, it's pretty simple.
logs = gson.fromJson(br, JsonLog[].class); // line 6
Provide the JsonLog
as an array JsonLog[].class