README.md

filtered-observable-collection

Real-time filtered ObservableList for Android Data binding.

This library is inspired by IFilteredReadOnlyObservableCollection interface of ReactiveProperty.

Download

repositories {
    maven { url "https://jitpack.io" }
}

dependencies {
    compile 'com.github.k-kagurazaka:filtered-observable-collection:1.0.1'
}

Usage

FilteredReadOnlyObservableList provides a real-time filtering view of ObservableList.

// create a source ObservableList
ObservableList<String> allList = new ObservableArrayList<>();

// create an ObservableList that only contains elements of which length less than 5
FilteredReadOnlyObservableList<String> filteredList
    = new FilteredReadOnlyObservableList<>(allList, it -> it.length() < 5);
    
// => filteredList == []

// when the source ObservableList changes, FilteredReadOnlyObservableList reflects the change
// with the specified filter
allList.addAll(Arrays.asList("e1", "e2", "long-name-e3", "long-name-e4", "e5"));

// => filteredList == ["e1", "e2", "e5"]

// change the filter
filteredList.setFilter(it -> it.contains("long"));

// => filteredList == ["long-name-e3", "long-name-e4"]

Observe changes of FilteredReadOnlyObservableList

FilteredReadOnlyObservableList implements ObservableList, then you can observe the changes as follows:

filteredList.addOnListChangedCallback(new ObservableList.OnListChangedCallback<ObservableList<String>>() {
    @Override
    public void onChanged(ObservableList<String> sender) {
        ...
    }

    @Override
    public void onItemRangeChanged(ObservableList<String> sender, int positionStart, int itemCount) {
        ...
    }

    @Override
    public void onItemRangeInserted(ObservableList<String> sender, int positionStart, int itemCount) {
        ...
    }

    @Override
    public void onItemRangeMoved(ObservableList<String> sender, int fromPosition, int toPosition, int itemCount) {
        ...
    }

    @Override
    public void onItemRangeRemoved(ObservableList<String> sender, int positionStart, int itemCount) {
        ...
    }
});

Unlike ObservableArrayList, FilteredReadOnlyObservableList raises change events when the elements implement Observable and it's property changes.

public class Animal extends BaseObservable {
    ...
}

ObservableList<Animal> sourceList = new ObservableArrayList<>();
sourceList.addAll(Arrays.asList(new Animal("Tom"), new Animal("Jerry")));

FilteredReadOnlyObservableList<Animal> filteredList
    = new FilteredReadOnlyObservableList<>(sourceList, it -> it.getName().length() > 3);

// when a property of elements of sourceList changes, filteredList raises onItemRangeChanged
sourceList.get(1).setName("Jerry Mouse");

// => filteredList == ["Jerry Mouse"]

// when a new element appears by a change of sourceList element property, filteredList raises onItemRangeInserted
sourceList.get(0).setName("Tom Cat");

// => filteredList == ["Tom Cat", "Jerry Mouse"]

License

The MIT License (MIT)

Copyright (c) 2016 Keita Kagurazaka

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.