This library extends ActiveAndroid to add support for fetcing results using a Loader.
It adds one class, ModelLoader.
Also see this pull request.
Say we have a model named Post. We can create a loader for this class which loads its results into an
ArrayAdapter (which could be used to back a ListView) and keeps it up-to-date like so:
ArrayAdapter<Post> mAdapter;
class PostLoader implements LoaderManager.LoaderCallbacks<List<Post>>
{
@Override
public Loader<List<Post>> onCreateLoader(int id, Bundle args)
{
return new ModelLoader<Post>(MainActivity.this, Post.class, true);
}
@Override
public void onLoadFinished(Loader<List<Post>> loader, List<Post> data)
{
mAdapter.clear();
mAdapter.addAll(data);
mAdapter.notifyDataSetChanged();
}
@Override
public void onLoaderReset(Loader<List<Post>> loader)
{
mAdapter.clear();
mAdapter.notifyDataSetChanged();
}
}This loader will query the database for all Post records and add them to the adapter. By using a ContentObserver
the Loader is updated whenever a change occurs to the Model table.
There are 3 constructors available for creating your ModelLoader.
/**
* Instantiates a new model loader. Will retrieve all models of the specified subclass. Will not
* be reloaded on relationship changes.
*
* @param context
* the model subclass you wish to query
* @param clazz
* the clazz
*/
public ModelLoader(Context context, Class<T> clazz);/**
* Instantiates a new model loader. Will retrieve all models of the specified subclass.
*
* @param context
* the context
* @param clazz
* the model subclass you wish to query
* @param updateOnRelationshipChanges
* if true, loader will updated when tables related to the one detected are changed
*/
public ModelLoader(Context context, Class<T> clazz, boolean updateOnRelationshipChanges);/**
* Instantiates a new model loader.
*
* @param context
* the context
* @param clazz
* the model subclass you wish to query
* @param from
* a select/from statement that will be executed to retrieve the objects
* @param updateOnRelationshipChanges
* if true, loader will updated when tables related to the one detected are changed
*/
public ModelLoader(Context context, Class<T> clazz, From from, boolean updateOnRelationshipChanges);Sor for example you could create a loader that would only load Posts where a member needsSync was true like so:
return new ModelLoader<Post>(MainActivity.this,
Post.class,
new Select()
.from(Post.class)
.where("needsSync == true"),
false);By setting updateOnRelationshipChanges to true, the loader will also be updated if a table that the main class has
a reference to is updated - for instance, if Post had a 1-M relationship with a table Tag, the model would be updated
when members of the Tag class are changed. This adds some overhead, so leave it off unless you need it.
An example project is included that shows the use of ModelLoaders with a custom SyncAdpater to keep a list of data up-to-date and syncronised with a fake webservice (no network stuff occurs for real). The credentials are included in the code - you can login with:
'''
email: foo@example.com
password: hello
'''
This project made available under the MIT License.
Copyright (C) 2013 3Squared Ltd.
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:
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