This is a simple example for booking movie seats in general movie/film mobile application. The concept is simply combined of State Design Pattern
, Android Data Binding
and Multibinding + Autofactory
below.
In the future, we can extend this concept by using RxJava
to handle behavior in only a stream, also chain any stream to process our logic.
Hope it will be useful for anyone who are building this context.
A seat has many states, such as:
- EMPTY: this is not a seat, just a blank space, it does not have any action.
- RESERVED: this is a reserved seat, which can not be booked anymore.
- AVAILABLE: this seat can be book by selecting.
- SELECTED: this seat is being selected, it can be deselected to be available.
To manage these states, we use State Design Pattern, also for the definition of state action, current state and switching between different states.
- An
available seat
can be select to be aselected seat
, its state changes fromAVAILABLE
toSELECTED
. - A
selected seat
can be deselected to be anavailable seat
, its state changes fromSELECTED
toAVAILABLE
For any state changes, we update the UI of the seat correspondingly by using @BindingAdapter
and @Bindable
annotations defined in Android Data Binding. Example:
- In a layout of a seat, we bind a state value to UI by:
app:state="@{data.state}"
. - A state defined in Java code is:
@Bindable State mState;
and must have getterpublic State getState() { return mState; }
. - If we want to seatChange the state and update to the UI, we set
mState = new NewState();
thennotifyPropertyChanged(BR.state);
, noted thatBR.state
is generated after building our application.
For the Dependency Injection, we use Dagger2 to setup. Dagger2 also supports Multibinding, it means that we can inject any ViewHolder
into our adapter to render the corresponding layout of an item in a list.
By using Autofactory, we construct some ViewHolders and provide these factory in a module. These factory must go with a key defined by @IntKey
, which is an item view type. Example:
@Provides
@IntoMap
@IntKey(Seat.Type.AVAILABLE)
SeatViewHolderFactory provideAvailableSeatViewHolder() {
return new AvailableSeatViewHolderFactory();
}
public interface SeatViewHolderFactory {
SeatViewHolder createViewHolder(ViewDataBinding binding);
}
@Override
public SeatViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
ItemSeatBinding binding = DataBindingUtil.inflate(LayoutInflater.from(parent.getContext()), R.layout.item_seat, parent, false);
return mSeatViewHolderFactoryMap.get(viewType).createViewHolder(binding);
}
- Write Unit Test to verify any action from the views.
- Support selecting many seats and handle exception if the selection reaches the maximum.
- Try to use RxJava to extend the concept.
- http://frogermcs.github.io/inject-everything-viewholder-and-dagger-2-example/
- https://github.com/google/android-ui-toolkit-demos/tree/master/DataBinding/DataBoundRecyclerView
MIT License
Copyright (c) 2017 Lam Tran (tranngoclam288@gmail.com)
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