Java tutorial
/* * Copyright (C) 2014 nohana, Inc. * Copyright 2017 Zhihu Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.xbm.android.matisse.internal.model; import android.content.Context; import android.database.Cursor; import android.os.Bundle; import android.support.v4.app.FragmentActivity; import android.support.v4.app.LoaderManager; import android.support.v4.content.Loader; import com.xbm.android.matisse.internal.loader.AlbumLoader; import java.lang.ref.WeakReference; public class AlbumCollection implements LoaderManager.LoaderCallbacks<Cursor> { private static final int LOADER_ID = 1; private static final String STATE_CURRENT_SELECTION = "state_current_selection"; private WeakReference<Context> mContext; private LoaderManager mLoaderManager; private AlbumCallbacks mCallbacks; private int mCurrentSelection; @Override public Loader<Cursor> onCreateLoader(int id, Bundle args) { Context context = mContext.get(); if (context == null) { return null; } return AlbumLoader.newInstance(context); } @Override public void onLoadFinished(Loader<Cursor> loader, Cursor data) { Context context = mContext.get(); if (context == null) { return; } mCallbacks.onAlbumLoad(data); } @Override public void onLoaderReset(Loader<Cursor> loader) { Context context = mContext.get(); if (context == null) { return; } mCallbacks.onAlbumReset(); } public void onCreate(FragmentActivity activity, AlbumCallbacks callbacks) { mContext = new WeakReference<Context>(activity); mLoaderManager = activity.getSupportLoaderManager(); mCallbacks = callbacks; } public void onRestoreInstanceState(Bundle savedInstanceState) { if (savedInstanceState == null) { return; } mCurrentSelection = savedInstanceState.getInt(STATE_CURRENT_SELECTION); } public void onSaveInstanceState(Bundle outState) { outState.putInt(STATE_CURRENT_SELECTION, mCurrentSelection); } public void onDestroy() { mLoaderManager.destroyLoader(LOADER_ID); mCallbacks = null; } public void loadAlbums() { mLoaderManager.initLoader(LOADER_ID, null, this); } public int getCurrentSelection() { return mCurrentSelection; } public void setStateCurrentSelection(int currentSelection) { mCurrentSelection = currentSelection; } public interface AlbumCallbacks { void onAlbumLoad(Cursor cursor); void onAlbumReset(); } }