double-loading-loaders's Introduction

Double Loading Loaders (1.1.0)

Introduction

Loader to implement the following flow:

Load in the background the cache and present the data
Load in the background the data via a network request, update the cache and represent the data
ForceLoad() on the loader to restart the flow from the network request only
Determine on onLoadFinished() in which Load State we are

Usage

In your app module build.gradle add the dependency, published in jCenter:

repositories {
    jcenter()
}
dependencies {
    (...)
    compile 'il.co.galex:double-loading-loaders:1.1.0'
}

Example

Extend the class DoubleLoadingAsyncLoader to implement the double loading flow

public class ChatLoader extends DoubleLoadingAsyncLoader<List<Chat>> {

    private final ChatDao chatDao;
    private String uuid;

    public ChatLoader(Context context, String uuid) {
        super(context);
        this.uuid = uuid;
        chatDao = new ChatDao(getContext());
    }
    @Override
    public List<Chat> loadCacheInBackground() {
        return chatDao.findAll();
    }

    @Override
    public List<Chat> loadNetworkInBackground() {
        chatDao.insertOrUpdate(ApiHelper.getUserChats(uuid)); // API call + Update of Database
        return chatDao.findAll(); // reload from database as the data is merged by the previous line
    }
}

in onLoadFinished(), to determine in what step of the flow we are, use DoubleLoaderUtils.getLoadState(loader)

 @Override
    public void onLoadFinished(Loader<List<Comment>> loader, List<Chat> data) {

        final LoadState loadState = DoubleLoaderUtils.getLoadState(loader);
        android.util.Log.d(TAG, "onLoadFinished() called with: load state = " + loadState);
        if (loadState == LoadState.NETWORK_LOADED || loadState == LoadState.NETWORK_RELOADED) {
            //TODO remove the loading indicator
        }

        // TODO set data in your adapter
    }