/*
* Copyright (C) 2017 Team Gateship-One
* (Hendrik Borghorst & Frederik Luetkes)
*
* The AUTHORS.md file contains a detailed contributors list:
* <https://github.com/gateship-one/odyssey/blob/master/AUTHORS.md>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package org.gateshipone.odyssey.fragments;
import android.content.ComponentCallbacks2;
import android.content.Context;
import android.content.res.Configuration;
import android.database.DataSetObserver;
import android.support.v4.app.Fragment;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.Loader;
import android.support.v4.widget.SwipeRefreshLayout;
import android.view.View;
import android.widget.AbsListView;
import org.gateshipone.odyssey.adapter.GenericSectionAdapter;
import org.gateshipone.odyssey.listener.ToolbarAndFABCallback;
import org.gateshipone.odyssey.models.GenericModel;
import org.gateshipone.odyssey.playbackservice.PlaybackServiceConnection;
import java.util.List;
abstract public class OdysseyFragment<T extends GenericModel> extends Fragment implements LoaderManager.LoaderCallbacks<List<T>> {
/**
* Callback to setup toolbar and fab
*/
protected ToolbarAndFABCallback mToolbarAndFABCallback;
/**
* The reference to the possible refresh layout
*/
protected SwipeRefreshLayout mSwipeRefreshLayout;
/**
* The reference to the possible abstract list view
*/
protected AbsListView mListView;
/**
* The reference to the possible empty view which should replace the list view if no data is available
*/
protected View mEmptyView;
/**
* ServiceConnection object to communicate with the PlaybackService
*/
protected PlaybackServiceConnection mServiceConnection;
/**
* The generic adapter for the view model
*/
protected GenericSectionAdapter<T> mAdapter;
/**
* Callback to check the current memory state
*/
private OdysseyComponentCallback mComponentCallback;
/**
* Observer to be notified if the dataset of the adapter changed.
*/
private OdysseyDataSetObserver mDataSetObserver;
/**
* Holds if data is ready of has to be refetched (e.g. after memory trimming)
*/
private boolean mDataReady;
/**
* Holds if trimming for this Fragment is currently allowed or not.
*/
private boolean mTrimmingEnabled;
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (null == mComponentCallback) {
mComponentCallback = new OdysseyComponentCallback();
}
// Register the memory trim callback with the system.
context.registerComponentCallbacks(mComponentCallback);
// This makes sure that the container activity has implemented
// the callback interface. If not, it throws an exception
try {
mToolbarAndFABCallback = (ToolbarAndFABCallback) context;
} catch (ClassCastException e) {
throw new ClassCastException(context.toString() + " must implement ToolbarAndFABCallback");
}
}
@Override
public void onDetach() {
super.onDetach();
// Unregister the memory trim callback with the system.
getActivity().getApplicationContext().unregisterComponentCallbacks(mComponentCallback);
}
/**
* Called when the fragment resumes.
* <p/>
* Create the PBS connection, reload the data and start the refresh indicator if a refreshlayout exists.
*/
@Override
public void onResume() {
super.onResume();
if (null == mDataSetObserver) {
mDataSetObserver = new OdysseyDataSetObserver();
}
mAdapter.registerDataSetObserver(mDataSetObserver);
mServiceConnection = new PlaybackServiceConnection(getActivity().getApplicationContext());
mServiceConnection.openConnection();
getContent();
mTrimmingEnabled = false;
}
@Override
public void onPause() {
super.onPause();
mTrimmingEnabled = true;
mAdapter.unregisterDataSetObserver(mDataSetObserver);
}
/**
* Method to reload the data and start the refresh indicator if a refreshlayout exists.
*/
public void refreshContent() {
if (mSwipeRefreshLayout != null) {
mSwipeRefreshLayout.post(new Runnable() {
@Override
public void run() {
mSwipeRefreshLayout.setRefreshing(true);
}
});
}
mDataReady = false;
getLoaderManager().restartLoader(0, getArguments(), this);
}
/**
* Checks if data is available or not. If not it will start getting the data.
* This method should be called from onResume and if the fragment is part of an view pager,
* every time the View is activated because the underlying data could be cleaned because
* of memory pressure.
*/
public void getContent() {
// Check if data was fetched already or not (or removed because of trimming)
if (!mDataReady) {
if (mSwipeRefreshLayout != null) {
mSwipeRefreshLayout.post(new Runnable() {
@Override
public void run() {
mSwipeRefreshLayout.setRefreshing(true);
}
});
}
// Prepare loader ( start new one or reuse old )
getLoaderManager().initLoader(0, getArguments(), this);
}
}
/**
* Called when the loader finished loading its data.
* <p/>
* The refresh indicator will be stopped if a refreshlayout exists.
* If the new model is empty a special empty view will be shown if exists.
*
* @param loader The used loader itself
* @param model Data of the loader
*/
@Override
public void onLoadFinished(Loader<List<T>> loader, List<T> model) {
if (mSwipeRefreshLayout != null) {
mSwipeRefreshLayout.post(new Runnable() {
@Override
public void run() {
mSwipeRefreshLayout.setRefreshing(false);
}
});
}
// Indicate that the data is ready now.
mDataReady = true;
// Transfer the data to the adapter so that the views can use it
mAdapter.swapModel(model);
}
/**
* This method can be used to prevent one fragment from triming its necessary data (e.g. active in a pager)
*
* @param enabled Enable the memory trimming
*/
public void enableMemoryTrimming(boolean enabled) {
mTrimmingEnabled = enabled;
}
/**
* If the loader is reset, the model data should be cleared.
*
* @param loader Loader that was resetted.
*/
@Override
public void onLoaderReset(Loader<List<T>> loader) {
// Clear the model data of the adapter.
mAdapter.swapModel(null);
}
/**
* Method to apply a filter to the view model of the fragment.
*/
public void applyFilter(String filter) {
mAdapter.applyFilter(filter);
}
/**
* Method to remove a previous set filter.
*/
public void removeFilter() {
mAdapter.removeFilter();
}
/**
* Method to show or hide the listview according to the state of the adapter.
*/
private void updateView() {
if (mListView != null && mEmptyView != null) {
if (mAdapter.isEmpty()) {
// show empty message
mListView.setVisibility(View.GONE);
mEmptyView.setVisibility(View.VISIBLE);
} else {
// show list view
mListView.setVisibility(View.VISIBLE);
mEmptyView.setVisibility(View.GONE);
}
}
}
/**
* Private callback class used to monitor the memory situation of the system.
* If memory reaches a certain point, we will relinquish our data.
*/
private class OdysseyComponentCallback implements ComponentCallbacks2 {
@Override
public void onTrimMemory(int level) {
if (mTrimmingEnabled && level >= TRIM_MEMORY_RUNNING_LOW) {
getLoaderManager().destroyLoader(0);
mDataReady = false;
}
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
}
@Override
public void onLowMemory() {
}
}
/**
* Private observer class to keep informed if the dataset of the adapter has changed.
* This will trigger an update of the view.
*/
private class OdysseyDataSetObserver extends DataSetObserver {
@Override
public void onInvalidated() {
super.onInvalidated();
updateView();
}
@Override
public void onChanged() {
super.onChanged();
updateView();
}
}
}