[英]RecyclerView chat load more items from top
我正在尝试在recyclerview中实现分页,以在用户滚动到顶部时加载更多聊天消息,这是通过向API发送最后一条消息时间(即Coverations [0]时间)来实现的,但是当添加新列表时,旧列表会得到重复了很多次。 我认为这是因为我没有适当地更新时间,实现此目的的正确方法是什么?
这是我正在使用的代码,第一次将标志设置为false且时间为空。
getConvoData(k, " ", "", false);
private String last_msg_time = " ";
private Boolean flag = false;
rv_convo.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if (!recyclerView.canScrollVertically(-1)) {
if (conversations != null) {
String time = last_msg_time;
getConvoData(k, " ", time, true);
}
}
}
});
这是获取对话数据的方法
private void getConvoData(final String k, final String new_message, final String last_time, final boolean flag) {
final String token1 = Global.shared().tb_token;
final String url = "https://app.aer.media/v2/message_router/_getChat";
final JSONObject jsonBody = new JSONObject();
final ProgressDialog progressDialog = new ProgressDialog(this);
final String mRequestBody = jsonBody.toString();
StringRequest stringRequest = new StringRequest(Request.Method.POST, url, new com.android.volley.Response.Listener<String>() {
@Override
public void onResponse(String response) {
try {
JSONObject jObj = new JSONObject(response);
final JSONObject data = jObj.getJSONObject("data");
conversations = data.getJSONArray("conversation");
JSONObject for_chat = data.getJSONObject("for_chat");
JSONArray jsonArr_chat = new JSONArray();
jsonArr_chat.put(for_chat);
params = (RelativeLayout.LayoutParams) rv_convo.getLayoutParams();
GsonBuilder gsonBuilder = new GsonBuilder();
Gson gson = gsonBuilder.create();
if (!flag) {
convobeans = gson.fromJson(conversations.toString(), convType);
last_msg_time = conversations.getJSONObject(0).getString("time");
Log.d("OldList", convobeans.toString());
adapter = new ChatDetailsAdapter(forChatBeen, convobeans, ChatDetailsActivity.this, forChatBeansList, image, name, initials, new_message, bitmap);
// Collections.reverse(convobeans);
rv_convo.setAdapter(adapter);
rv_convo.smoothScrollToPosition( rv_convo.getAdapter().getItemCount() - 1);
adapter.notifyDataSetChanged();
rv_convo.setNestedScrollingEnabled(true);
} else {
newConvo = gson.fromJson(conversations.toString(), convType);
last_msg_time = conversations.getJSONObject(0).getString("time");
if (newConvo != null && newConvo.size() > 0) {
Log.d("newList", newConvo.toString());
convobeans.addAll(0, newConvo);
adapter.notifyItemChanged(0, newConvo.size());
}
}
}
}
}
根据标志,我将更新列表并同时更新时间,但是由于之前的时间过去,该列表在RecyclerView
重复出现,如何最佳地更新时间并每次获取新列表?
当用户在
recylerview
scroll down
时,此代码用于获取数据。 只需分析这段代码,您就会了解基本思想。
rvCategory.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (dy > 0) {
visibleItemCount = mLinearLayoutManager.getChildCount();
totalItemCount = mLinearLayoutManager.getItemCount();
pastVisiblesItems = mLinearLayoutManager.findFirstVisibleItemPosition();
if (loading) {
if ((visibleItemCount + pastVisiblesItems) >= totalItemCount) {
loading = false;
fetchData();
}
}
}
}
});
函数FetchData()
private void fetchData() {
String url = EndPoints.location + "getMobileData.php?lastData=" + lastData;
JsonObjectRequest jsObjRequest = new JsonObjectRequest
(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
lastData = response.getString("last");
JSONArray jArray = response.getJSONArray("response");
if (jArray.length() == 0) {
//Empty condition
} else {
for (int i = 0; i < jArray.length(); i++) {
//Append the chat with the Dataobject of your modelAnd swap the recylerview view with new data
//Example
}
adapter.swap(rvHomeModel.createHomeList(DataPathsHome, true));
}
} catch (JSONException e) {
e.printStackTrace();
}
loading = true;
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// TODO Auto-generated method stub
loading = true;
Toast.makeText(CategoryView.this, "No internet connection", Toast.LENGTH_LONG).show();
}
});
// Add a request (in this example, called stringRequest) to your RequestQueue.
MySingleton.getInstance(this).addToRequestQueue(jsObjRequest);
}
在您的适配器类中创建一个名为swap的函数,该函数接受新数据集
public void swap(List<rvHomeModel> list) {
//Check your previouse dataset used in adapter is empty or not
if (rvHomeModels!= null) {
rvHomeModels.clear();
rvHomeModels.addAll(list);
} else {
rvHomeModels = list;
}
notifyDataSetChanged();
}
在服务器上
1.获取先前的值
2.执行数据库操作并获取上一个的聊天ID <
2.创建一个JSON对象包含
{
last:last_chat_id,
response:{
//Your chat
}
}
对于这个问题,这不是一个完美的解决方案。 但是您将获得有关所需内容的基本想法。
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