<分区>
在我的 firebase 数据库中，我正在存储这样的数据
pic 2 .
现在我想根据时间戳从 firebase 实时数据库中的 RecyclerView 上以降序/最新顺序检索和显示数据。
我已经尝试过 layoutmanager.setReverseLayout(true); 和
layoutmanager.setStackFromEnd(true); 用于反转 RecyclerView 但它总是从中间显示数据，而且我不想遵循这种方法。
因为我将所有数据添加到 ArrayList resultsHistory 中。现在我如何根据最新的时间戳对 Arraylist 进行排序，然后设置我的适配器？它能解决问题吗？
下面是我的代码:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_history);
customerOrDriver = getIntent().getExtras().getString("customerOrDriver");
sharedPreferences = PreferenceManager.getDefaultSharedPreferences(HistoryActivity.this);
userId = sharedPreferences.getString("UID", "");
mHistoryRecyclerView = (RecyclerView) findViewById(R.id.historyRecyclerView);
//mHistoryAdapter = new HistoryAdapter(getDataSetHistory(), HistoryActivity.this);
mHistoryLayoutManager = new LinearLayoutManager(HistoryActivity.this);
mHistoryRecyclerView.setLayoutManager(mHistoryLayoutManager);
mHistoryRecyclerView.setHasFixedSize(true);
/*// sort the recycler view to descending order
((LinearLayoutManager) mHistoryLayoutManager).setReverseLayout(true);
((LinearLayoutManager) mHistoryLayoutManager).setStackFromEnd(true);*/
mHistoryRecyclerView.setItemAnimator(new DefaultItemAnimator());
mHistoryRecyclerView.addItemDecoration(new DividerItemDecoration(this, LinearLayoutManager.VERTICAL));
// mHistoryRecyclerView.setAdapter(mHistoryAdapter);
getUserHistoryIds();
}
private void getUserHistoryIds() {
//swipeRefreshLayout.setRefreshing(true);
DatabaseReference userHistoryDatabase = FirebaseDatabase.getInstance().getReference().child(Common.user_table).child(customerOrDriver).child(userId).child(Common.history_table);
userHistoryDatabase.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
for (DataSnapshot history : dataSnapshot.getChildren()) {
FetchRideInformation(history.getKey());
//swipeRefreshLayout.setRefreshing(false);
}
sortDate();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
//swipeRefreshLayout.setRefreshing(false);
}
});
}
private void FetchRideInformation(String rideKey) {
DatabaseReference historyDatabase = FirebaseDatabase.getInstance().getReference().child(Common.history_table).child(rideKey);
historyDatabase.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
String rideId = dataSnapshot.getKey();
timestamp = 0L;
for (DataSnapshot child : dataSnapshot.getChildren()) {
if (child.getKey().equals("timestamp")) {
timestamp = Long.valueOf(child.getValue().toString());
}
}
getRideInformation(rideId, timestamp);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
private void getRideInformation(final String rideId, final Long timestamp) {
DatabaseReference historyRideInfoDb = FirebaseDatabase.getInstance().getReference().child(Common.history_table).child(rideId);
historyRideInfoDb.addListenerForSingleValueEvent(new ValueEventListener() {
@SuppressLint("SetTextI18n")
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
for (DataSnapshot child : dataSnapshot.getChildren()) {
if (child.getKey().equals("patient")) {
patientId = child.getValue().toString();
if (!patientId.equals(userId)) {
userDriverOrCustomer = "Doctors";
getUserInformation("Patients", patientId, rideId, timestamp);
}
} else if (child.getKey().equals("patient")) {
patientId = child.getValue().toString();
if (!patientId.equals(userId)) {
userDriverOrCustomer = "Phamacys";
getUserInformation("Patients", patientId, rideId, timestamp);
}
}
if (child.getKey().equals("doctor")) {
doctorId = child.getValue().toString();
if (!doctorId.equals(userId)) {
userDriverOrCustomer = "Patients";
getUserInformation("Doctors", doctorId, rideId, timestamp);
}
} else if (child.getKey().equals("pharmacy")) {
pharmacyId = child.getValue().toString();
if (!pharmacyId.equals(userId)) {
userDriverOrCustomer = "Patients";
getUserInformation("Pharmacys", pharmacyId, rideId, timestamp);
}
}
}
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
private void getUserInformation(String otherUserDriverOrCustomer, String otherUserId, final String rideId, final Long timestamp) {
DatabaseReference mOtherUserDB = FirebaseDatabase.getInstance().getReference().child(Common.user_table).child(otherUserDriverOrCustomer).child(otherUserId);
mOtherUserDB.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
Map<String, Object> map = (Map<String, Object>) dataSnapshot.getValue();
if (map.get("name") != null) {
name = (map.get("name").toString());
}
if (map.get("service") == null) {
service = (map.get("phone").toString());
} else if (map.get("service") != null) {
service = (map.get("service").toString());
}
HistoryObject obj = new HistoryObject(rideId, name, service, getDate(timestamp), timestamp);
resultsHistory.add(obj);
mHistoryAdapter.notifyDataSetChanged();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
private String getDate(Long time) {
Calendar cal = Calendar.getInstance(Locale.getDefault());
cal.setTimeInMillis(time * 1000);
String date = DateFormat.format("MMMM dd yyyy, hh:mm a", cal).toString();
return date;
}
private ArrayList<HistoryObject> resultsHistory = new ArrayList<HistoryObject>();
private ArrayList<HistoryObject> getDataSetHistory() {
return resultsHistory;
}
@Override
public boolean onSupportNavigateUp() {
onBackPressed();
return true;
}
public void sortDate() {
/*Collections.sort(resultsHistory, new Comparator<HistoryObject>() {
DateFormat f = new SimpleDateFormat("MMMM dd yyyy, hh:mm a");
@Override
public int compare(HistoryObject lhs, HistoryObject rhs) {
try {
return f.parse(lhs.getTime()).compareTo(f.parse(rhs.getTime()));
} catch (ParseException e) {
throw new IllegalArgumentException(e);
}
}
});*/
Collections.sort(resultsHistory, new Comparator<HistoryObject>() {
public int compare(HistoryObject o1, HistoryObject o2) {
if (o1.getT() == null || o2.getT() == null)
return 0;
return o2.getT().compareTo(o1.getT());
}
});
mHistoryAdapter = new HistoryAdapter(resultsHistory, HistoryActivity.this);
mHistoryRecyclerView.setAdapter(mHistoryAdapter);
}