Java tutorial
package com.dm.wallpaper.board.fragments; import android.content.res.Configuration; import android.os.AsyncTask; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v4.app.Fragment; import android.support.v4.widget.SwipeRefreshLayout; import android.support.v7.widget.DefaultItemAnimator; import android.support.v7.widget.GridLayoutManager; import android.support.v7.widget.RecyclerView; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; import com.danimahardhika.android.helpers.core.ColorHelper; import com.danimahardhika.android.helpers.core.DrawableHelper; import com.danimahardhika.android.helpers.core.ViewHelper; import com.dm.wallpaper.board.R; import com.dm.wallpaper.board.R2; import com.dm.wallpaper.board.adapters.WallpapersAdapter; import com.dm.wallpaper.board.databases.Database; import com.dm.wallpaper.board.items.Wallpaper; import com.dm.wallpaper.board.preferences.Preferences; import com.dm.wallpaper.board.utils.LogUtil; import com.dm.wallpaper.board.utils.listeners.WallpaperListener; import java.util.ArrayList; import java.util.List; import butterknife.BindView; import butterknife.ButterKnife; import static com.dm.wallpaper.board.helpers.ViewHelper.resetViewBottomPadding; /* * Wallpaper Board * * Copyright (c) 2017 Dani Mahardhika * * 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. */ public class FavoritesFragment extends Fragment implements WallpaperListener { @BindView(R2.id.recyclerview) RecyclerView mRecyclerView; @BindView(R2.id.swipe) SwipeRefreshLayout mSwipe; @BindView(R2.id.favorite_empty) ImageView mFavoriteEmpty; private AsyncTask<Void, Void, Boolean> mGetWallpapers; @Nullable @Override public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { View view = inflater.inflate(R.layout.fragment_wallpapers, container, false); ButterKnife.bind(this, view); if (!Preferences.get(getActivity()).isShadowEnabled()) { View shadow = ButterKnife.findById(view, R.id.shadow); if (shadow != null) shadow.setVisibility(View.GONE); } return view; } @Override public void onActivityCreated(@Nullable Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); resetViewBottomPadding(mRecyclerView, true); mSwipe.setEnabled(false); mRecyclerView.setItemAnimator(new DefaultItemAnimator()); mRecyclerView.setLayoutManager(new GridLayoutManager(getActivity(), getActivity().getResources().getInteger(R.integer.wallpapers_column_count))); mRecyclerView.setHasFixedSize(false); getWallpapers(); } @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); ViewHelper.resetSpanCount(mRecyclerView, getActivity().getResources().getInteger(R.integer.wallpapers_column_count)); resetViewBottomPadding(mRecyclerView, true); } @Override public void onDestroy() { if (mGetWallpapers != null) mGetWallpapers.cancel(true); super.onDestroy(); } @Override public void onWallpaperSelected(int position) { if (mRecyclerView == null) return; if (position < 0 || position > mRecyclerView.getAdapter().getItemCount()) return; mRecyclerView.scrollToPosition(position); } private void getWallpapers() { mGetWallpapers = new AsyncTask<Void, Void, Boolean>() { List<Wallpaper> wallpapers; @Override protected void onPreExecute() { super.onPreExecute(); wallpapers = new ArrayList<>(); } @Override protected Boolean doInBackground(Void... voids) { while (!isCancelled()) { try { Thread.sleep(1); wallpapers = Database.get(getActivity()).getFavoriteWallpapers(); return true; } catch (Exception e) { LogUtil.e(Log.getStackTraceString(e)); return false; } } return false; } @Override protected void onPostExecute(Boolean aBoolean) { super.onPostExecute(aBoolean); if (aBoolean) { mRecyclerView.setAdapter(new WallpapersAdapter(getActivity(), wallpapers, true, false)); if (mRecyclerView.getAdapter().getItemCount() == 0) { int color = ColorHelper.getAttributeColor(getActivity(), android.R.attr.textColorSecondary); mFavoriteEmpty.setImageDrawable(DrawableHelper.getTintedDrawable(getActivity(), R.drawable.ic_wallpaper_favorite_empty, ColorHelper.setColorAlpha(color, 0.7f))); mFavoriteEmpty.setVisibility(View.VISIBLE); } } mGetWallpapers = null; } }.execute(); } }