package edu_cn.pku.course.fragments;
import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
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.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Set;
import edu_cn.pku.course.CourseInfo;
import edu_cn.pku.course.Utils;
import edu_cn.pku.course.activities.R;
import edu_cn.pku.course.activities.SplashActivity;
import edu_cn.pku.course.adapter.CourseListRecyclerViewAdapter;
public class CourseListFragment extends Fragment implements SwipeRefreshLayout.OnRefreshListener {
private CoursesLoadingTask mLoadingTask = null;
private RecyclerView mRecyclerView = null;
private boolean showLongPressHintFlag = false;
private SwipeRefreshLayout mCourseListSwipeContainer;
private CourseListRecyclerViewAdapter adapter;
public CourseListFragment() {
// Required empty public constructor
}
/**
* 传递参数用的，这里没用到。
*
* @return A new instance of fragment CourseListFragment.
*/
public static CourseListFragment newInstance() {
CourseListFragment fragment = new CourseListFragment();
Bundle args = new Bundle();
fragment.setArguments(args);
return fragment;
}
public void showLongPressHint() {
if (mRecyclerView == null || !mRecyclerView.isAttachedToWindow()) {
showLongPressHintFlag = true;
return;
}
Snackbar.make(mRecyclerView, "温馨提示：长按课程可以置顶", Snackbar.LENGTH_LONG)
.setAction("我知道了", new View.OnClickListener() {
@Override
public void onClick(View v) {
SharedPreferences sharedPreferences = SplashActivity.contextOfApplication.getSharedPreferences("longPressHint", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putBoolean("showed", true);
editor.apply();
}
})
.show();
showLongPressHintFlag = false;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// if (getArguments() != null) {
// }
}
@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_course_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_courses);
mCourseListSwipeContainer = linearLayout.findViewById(R.id.course_list_swipe_container);
// 设置动画
LayoutAnimationController animation = AnimationUtils.loadLayoutAnimation(getContext(), R.anim.layout_animation_fall_down);
mCourseListSwipeContainer.setLayoutAnimation(animation);
// 设置刷新的监听类为此类（监听函数onRefresh）
mCourseListSwipeContainer.setOnRefreshListener(this);
mCourseListSwipeContainer.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("pinnedCourseList", Context.MODE_PRIVATE);
adapter = new CourseListRecyclerViewAdapter(new ArrayList<CourseInfo>(), sharedPreferences, this);
mRecyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
mRecyclerView.setAdapter(adapter);
try {
String cachedCourseList = getCachedCourseList();
if (cachedCourseList == null)
throw new Exception();
updateAdapter(cachedCourseList, false);
} catch (Exception e) {
// 显示Loading的小动画，并在后台读取课程列表
showLoading(true);
mLoadingTask = new CoursesLoadingTask();
mLoadingTask.execute((Void) null);
}
return linearLayout;
}
@Override
public void onRefresh() {
if (mLoadingTask == null) {
mLoadingTask = new CoursesLoadingTask();
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);
}
});
mCourseListSwipeContainer.setRefreshing(show);
}
private void saveCachedCourseList(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("course_list_str", rootNodeStr);
editor.apply();
}
private String getCachedCourseList() 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("course_list_str", null);
}
private void updateAdapter(String rootNodeStr, boolean showAnimation) {
Node rootNode = Utils.stringToNode(rootNodeStr);
if (rootNode != null) {
FragmentActivity fa = getActivity();
if (fa == null) {
return;
}
SharedPreferences sharedPreferences = fa.getSharedPreferences("pinnedCourseList", Context.MODE_PRIVATE);
Set<String> hset = sharedPreferences.getStringSet("key", null);
if (hset == null)
hset = new HashSet<>();
ArrayList<CourseInfo> courses_list = new ArrayList<>();
NodeList nCoursesList = rootNode.getFirstChild().getChildNodes();
for (int temp = 0; temp < nCoursesList.getLength(); temp++) {
CourseInfo ci = new CourseInfo((Element) nCoursesList.item(temp));
if (hset.contains(ci.getRawCourseName()))
ci.setPinned(1);
courses_list.add(ci);
}
adapter.updateList(courses_list);
// 显示课程列表的fancy的动画
if (showAnimation)
mRecyclerView.scheduleLayoutAnimation();
if (showLongPressHintFlag)
showLongPressHint();
}
}
@SuppressLint("StaticFieldLeak")
private class CoursesLoadingTask extends AsyncTask<Void, Void, String> {
CoursesLoadingTask() {
}
@Override
protected String doInBackground(Void... params) {
return Utils.courseHttpGetRequest("http://course.pku.edu.cn/webapps/Bb-mobile-bb_bb60/dashboard?course_type=ALL&with_notifications=false");
}
@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 {
// 解析返回的HTML
updateAdapter(str, true);
try {
saveCachedCourseList(str);
} catch (Exception e) {
e.printStackTrace();
}
}
}
// 没什么用的函数
@Override
protected void onCancelled() {
mLoadingTask = null;
showLoading(false);
}
}
}
