arg

arg module provides @Arg annotation.

@Arg

Annotation for generating newInstance() methods for your Fragment classes.

Without using this library you would have to write this:

public class MyFragment extends Fragment {

    private static final String ARG_TEXT = "arg_text";
    private static final String ARG_DATA = "arg_data";

    public static MyFragment newInstance(String text, MyData data) {
        MyFragment frag = new MyFragment();
        Bundle args = new Bundle();
        args.putString(ARG_TEXT, text);
        args.putParcelable(ARG_DATA, data);
        frag.setArguments(args);
        return frag;
    }

    private String mText;
    private MyData mData;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mText = getArguments().getString(ARG_TEXT);
        mData = (MyData) getArguments().getParcelable(ARG_DATA);
    }
}

But with this library you can write this:

public class MyFragment extends Fragment {

    @Arg
    String mText;
    @Arg
    MyData mData;

}

Class blade.F (= Fragment) is automatically generated for you. This class contains 1 method for each Fragment class with annotated fields:

• X newX(T1 arg1[, T2 arg2, ...]) - Creates new instance of class X.

e.g. for MyFragment class it contains method named newMyFragment(...) with 2 parameters: String and MyData. So you can easily create new fragment by calling:

F.newMyFragment("some-string", new MyData());

And given values will be injected to the corresponding fields annotated with @Arg at the beginning of onCreate(Bundle) method.

Class blade.F is not final so that you can extend it and add more methods.

Custom serialization

Since version 2.6.0 you can supply a class parameter to the annotation. This class should implement the blade.Bundler interface and you can use it to provide custom serialization and deserialization for your types.

Example:

public class MyFragment extends Fragment {

    @Arg(MyTypeBundler.class)
    MyType mMyType;
}

public class MyTypeBundler implements Bundler<MyType> {

    void save(@Nullable final MyType value, @NonNull final Bundle state) {
        // save given value to the state
    }
    
    @Nullable
    MyType restore(@NonNull final Bundle state) {
        // restore and return value from state
    }
}