Convert ints to booleans

Question

Is there a way that I can convert int/short values to booleans? I'm receiving JSON that looks like this:

{ is_user: "0", is_guest: "0" } 

I'm trying to serialize it into a type that looks like this:

class UserInfo {      @SerializedName("is_user")     private boolean isUser;      @SerializedName("is_guest")     private boolean isGuest;      /* ... */ } 

How can I make Gson translate these int/short fields into booleans?

Answer 1

Start by getting Gson 2.2.2 or later. Earlier versions (including 2.2) don't support type adapters for primitive types. Next, write a type adapter that converts integers to booleans:

private static final TypeAdapter<Boolean> booleanAsIntAdapter = new TypeAdapter<Boolean>() {   @Override public void write(JsonWriter out, Boolean value) throws IOException {     if (value == null) {       out.nullValue();     } else {       out.value(value);     }   }   @Override public Boolean read(JsonReader in) throws IOException {     JsonToken peek = in.peek();     switch (peek) {     case BOOLEAN:       return in.nextBoolean();     case NULL:       in.nextNull();       return null;     case NUMBER:       return in.nextInt() != 0;     case STRING:       return Boolean.parseBoolean(in.nextString());     default:       throw new IllegalStateException("Expected BOOLEAN or NUMBER but was " + peek);     }   } }; 

... and then use this code to create the Gson instance:

  Gson gson = new GsonBuilder()       .registerTypeAdapter(Boolean.class, booleanAsIntAdapter)       .registerTypeAdapter(boolean.class, booleanAsIntAdapter)       .create();