Support use default value by set null as parameter

[talenguyen]

There is no reason to set and get null value into the Bundle object.

So

null will not be set as an extra value. That mean, if you set null as the parameter then the target Activity/Fragment/Service will not get that value.

TargetActivity

@Extra String name;
@Extra int age;

@Override public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    PrettyBundle.inject(this); // call to inject the extra.
}

Set extras with null for the TargetActivity

Intent intent = Activities.createTargetActivityIntent(null, null);
startActivity(intent);

Then

TargetActivity.name //take class variable default value.
TargetActivity.age //take class variable default value.