travisdachi

krefson["someKey"] = someData //put
val data = krefson["someKey", defalutValue] //get with default value
val anotherData: SomeData? = krefson["someOtherKey"] //get nullable
if ("someKey" in krefson) //check if "someKey" is exist
krefson.remove("someKey") //simply remove a key

travisdachi

inline fun <reified T> Gson.fromJson(string: String?): T? {
    return fromJson(string, object : TypeToken<T>() {}.type)
}

travisdachi

open class Krefson(context: Context, val name: String, val gson: Gson = Gson()) {

    val sharedPreference: SharedPreferences = context.getSharedPreferences(name, Context.MODE_PRIVATE)

    inline operator fun <reified T> get(key: String): T? {
        return gson.fromJson(sharedPreference.getString(key, null))
    }

    inline operator fun <reified T> get(key: String, defaultValue: T): T {
        return gson.fromJson(sharedPreference.getString(key, null)) ?: defaultValue

travisdachi

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    android:orientation="vertical"
    tools:context="com.example.travis.playground.MainActivity">

travisdachi

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

travisdachi

public class PersonAdapter extends RecyclerView.Adapter<PersonAdapter.PersonHolder> {

    private List<Person> list;

    public PersonAdapter(@NonNull List<Person> list) {
        this.list = list;
    }

    @Override
    public PersonHolder onCreateViewHolder(ViewGroup parent, int viewType) {

travisdachi

public class Person {
    public String name;
    public int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
}

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public class MainActivity extends AppCompatActivity {

    RecyclerView recyclerView;
    List<Person> people;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        recyclerView = (RecyclerView) findViewById(R.id.recyclerView);

travisdachi

public class Person {
    public String name;
    public int age;
    public boolean isChecked;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
}

travisdachi

public class PersonAdapter extends RecyclerView.Adapter<PersonAdapter.PersonHolder> {

    private List<Person> list;

    public PersonAdapter(@NonNull List<Person> list) {
        this.list = list;
    }

    @Override
    public PersonHolder onCreateViewHolder(ViewGroup parent, int viewType) {