package edu_cn.pku.course.fragments;
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AnimationUtils;
import android.view.animation.LayoutAnimationController;
import android.widget.LinearLayout;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Locale;
import edu_cn.pku.course.Utils;
import edu_cn.pku.course.activities.R;
import edu_cn.pku.course.adapter.AnnouncementListRecyclerViewAdapter;
public class AnnouncementListFragment extends Fragment implements SwipeRefreshLayout.OnRefreshListener {
private AnnouncementLoadingTask mLoadingTask = null;
private RecyclerView mRecyclerView;
private SwipeRefreshLayout mAnnouncementListSwipeContainer;
private AnnouncementListRecyclerViewAdapter adapter;
public AnnouncementListFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
*
* @return A new instance of fragment CoursesListFragment.
*/
public static AnnouncementListFragment newInstance() {
AnnouncementListFragment fragment = new AnnouncementListFragment();
Bundle args = new Bundle();
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
LinearLayout linearLayout = (LinearLayout) inflater.inflate(R.layout.fragment_announcement_list, container, false);
// 查找xml文件中的对象并保存进Java变量
mRecyclerView = linearLayout.findViewById(R.id.recycler_announcement_list);
mAnnouncementListSwipeContainer = linearLayout.findViewById(R.id.announcement_swipe_container);
// 设置动画
LayoutAnimationController animation = AnimationUtils.loadLayoutAnimation(getContext(), R.anim.layout_animation_fall_down);
mAnnouncementListSwipeContainer.setLayoutAnimation(animation);
// 设置刷新的监听类为此类（监听函数onRefresh）
mAnnouncementListSwipeContainer.setOnRefreshListener(this);
mAnnouncementListSwipeContainer.setColorSchemeColors(getResources().getColor(R.color.colorPrimary), getResources().getColor(R.color.colorAccent));
FragmentActivity fa = getActivity();
// 为了消除编译器Warning，需要判断一下是不是null，其实这基本上不可能出现null
if (fa == null) {
return linearLayout;
}
// 将读取已置顶课程列表的SharedPreferences传递给CourseListRecyclerViewAdapter
// SharedPreferences sharedPreferences = fa.getSharedPreferences("pinnedAnnouncementList", Context.MODE_PRIVATE);
adapter = new AnnouncementListRecyclerViewAdapter(new ArrayList<AnnouncementInfo>(), this);
mRecyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
mRecyclerView.setAdapter(adapter);
try {
String cachedList = getCachedAnnouncementsList();
if (cachedList == null)
throw new Exception();
updateAdapter(cachedList, false);
} catch (Exception e) {
e.printStackTrace();
}
// 显示Loading的小动画，并在后台读取课程列表
showLoading(true);
mLoadingTask = new AnnouncementLoadingTask();
mLoadingTask.execute((Void) null);
return linearLayout;
}
@Override
public void onRefresh() {
if (mLoadingTask == null) {
mLoadingTask = new AnnouncementLoadingTask();
mLoadingTask.execute((Void) null);
}
}
@TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)
private void showLoading(final boolean show) {
// 逐渐显示mRecyclerView的小动画
int shortAnimTime = 200;
// mRecyclerView.setVisibility(show ? View.GONE : View.VISIBLE);
// mRecyclerView.animate().setDuration(shortAnimTime).alpha(
// show ? 0 : 1).setListener(new AnimatorListenerAdapter() {
// @Override
// public void onAnimationEnd(Animator animation) {
// mRecyclerView.setVisibility(show ? View.GONE : View.VISIBLE);
// }
// });
mAnnouncementListSwipeContainer.setRefreshing(show);
}
private void saveCachedAnnouncementsList(String rootNodeStr) throws Exception {
FragmentActivity fa = getActivity();
if (fa == null) {
throw new Exception("Unknown Error: Null getActivity()!");
}
SharedPreferences sharedPreferences = fa.getSharedPreferences("cached_xml", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString("announcement_list_str", rootNodeStr);
editor.apply();
}
private String getCachedAnnouncementsList() throws Exception {
FragmentActivity fa = getActivity();
if (fa == null) {
throw new Exception("Unknown Error: Null getActivity()!");
}
SharedPreferences sharedPreferences = fa.getSharedPreferences("cached_xml", Context.MODE_PRIVATE);
return sharedPreferences.getString("announcement_list_str", null);
}
private void updateAdapter(String rootNodeStr, boolean showAnimation) {
// 解析返回的HTML
ArrayList<AnnouncementInfo> announcement_list = new ArrayList<>();
FragmentActivity fa = getActivity();
if (fa == null) {
return;
}
Element list = Jsoup.parse(rootNodeStr).getElementById("announcementList");
if (list != null) {
Elements nList = list.children();
for (int temp = 0; temp < nList.size(); temp++) {
Element n = nList.get(temp);
announcement_list.add(new AnnouncementInfo(n));
}
}
adapter.updateList(announcement_list);
// 显示课程列表的fancy的动画
if (showAnimation)
mRecyclerView.scheduleLayoutAnimation();
}
/**
* 为了方便管理课程列表，将每个课程的各种信息组成一个类。
*/
public static class AnnouncementInfo implements Comparable<AnnouncementInfo> {
private Element nNode;
AnnouncementInfo(Element nNode) {
this.nNode = nNode;
}
public String getAuthorInfo() {
return nNode.getElementsByClass("announcementInfo").first().toString();
}
public String getContents() {
Element tmp = nNode.getElementsByClass("details").first().getElementsByClass("vtbegenerated").first();
return tmp == null ? "" : tmp.toString();
}
public String getAnnouncementTitle() {
return nNode.child(0).text();
}
public String getAnnouncementDate() {
return nNode.getElementsByClass("details").first().child(0).text().replace("发帖时间: ", "");
}
public String getAnnouncementId() {
return nNode.attr("id");
}
//给出可以比较的Date类型
private Date changeToDate() throws ParseException {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy年M月d日", Locale.CHINA);
return dateFormat.parse(getAnnouncementDate().split(" ")[0]);
}
@Override
public int compareTo(AnnouncementListFragment.AnnouncementInfo comp) {
try {
// if (this.changeToDate() == comp.changeToDate())
return comp.changeToDate().compareTo(this.changeToDate());
} catch (ParseException e) {
// e.printStackTrace();//这个是字符串不符合定义的格式的错误
}
return this.getAnnouncementTitle().compareTo(comp.getAnnouncementTitle());
}
}
@SuppressLint("StaticFieldLeak")
private class AnnouncementLoadingTask extends AsyncTask<Void, Void, String> {
AnnouncementLoadingTask() {
}
//主要是有个course id一串数字是不一样的
@Override
protected String doInBackground(Void... params) {
return Utils.courseHttpGetRequest("http://course.pku.edu.cn/webapps/blackboard/execute/announcement?method=search&returnUrl=/webapps/portal/execute/tabs/tabAction?tab_tab_group_id=_3_1&tabId=_1_1");
}
@Override
protected void onPostExecute(final String str) {
mLoadingTask = null;
showLoading(false);
// 出现了错误
if (str.startsWith(Utils.errorPrefix)) {
if (str.equals(Utils.errorPrefix + Utils.errorPasswordIncorrect)) {
// 密码错误
try {
Utils.SignOut(getActivity());
} catch (Exception e) {
if (mRecyclerView.isAttachedToWindow())
Snackbar.make(mRecyclerView, e.getMessage(), Snackbar.LENGTH_SHORT).show();
}
} else {
// 其他网络错误
if (mRecyclerView.isAttachedToWindow())
Snackbar.make(mRecyclerView, str, Snackbar.LENGTH_SHORT).show();
}
} else {
updateAdapter(str, true);
try {
saveCachedAnnouncementsList(str);
} catch (Exception e) {
e.printStackTrace();
}
}
}
// 没什么用的函数
@Override
protected void onCancelled() {
mLoadingTask = null;
showLoading(false);
}
}
}
