添加新项目时,Android Firebase 聊天 RecyclerView 会自动滚动到底部 [英] Android Firebase chat RecyclerView auto scroll to bottom when new item is added
本文介绍了添加新项目时,Android Firebase 聊天 RecyclerView 会自动滚动到底部的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我正在使用 firebase 开发一个 android 聊天.
im developing an android chat using firebase.
我试图研究这个问题,但我找不到好的解决方案.
i tried to research about this problem but i cant find a good solutions.
希望有人能帮助我.
我的问题我希望 RecyclerView 在添加新项目时自动滚动.
my problem i want the RecyclerView to auto scroll if new item is added.
这是我的代码.
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
View rootView = inflater.inflate(R.layout.chatlayoutchat, container, false);
Connectivity connectivity=new Connectivity();
if(connectivity.isConnected(getActivity())) {
if(getArguments() != null) {
Firebase.setAndroidContext(this.getActivity());
String ccustomersid = getArguments().getString("customersid");
String creferralae = getArguments().getString("referralae");
String ccustomersname = getArguments().getString("customersname");
customersid = ccustomersid;
referralae = creferralae;
customersname = ccustomersname;
Firebase.setAndroidContext(this.getActivity());
editText = (EditText) rootView.findViewById(R.id.editText);
sendbutton = (Button) rootView.findViewById(R.id.button);
mRecyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);
RecyclerView.LayoutManager layoutmgr = new LinearLayoutManager(getActivity());
mRecyclerView.setLayoutManager(layoutmgr);
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
final LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
//linearLayoutManager.setReverseLayout(true);
linearLayoutManager.setStackFromEnd(true);
mRecyclerView.setLayoutManager(linearLayoutManager);
from_user = customersid;
to_user = referralae;
LoggedInUser = customersname;
//Log.v("NODE CREATED:", from_user + " " + to_user);
ref_chatchildnode1 = firebase_chatnode.child(from_user + " " + to_user);
//ref_chatchildnode2 = firebase_chatnode.child(to_user + " " + from_user);
sendbutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
newmsg = editText.getText().toString().trim();
ChatModel m = new ChatModel();
m.setSender(LoggedInUser);
m.setMessage(newmsg);
ref_chatchildnode1.push().setValue(m);
//ref_chatchildnode2.push().setValue(m);
editText.setText("");
}
});
ref_chatchildnode1.addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
ChatModel chatmsg = dataSnapshot.getValue(ChatModel.class);
chatmsgsList.add(chatmsg);
}
@Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
}
@Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
@Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
});
}
}else{
nointernet();
}
showGlobalContextActionBar();
return rootView;
}
@Override
public void onStart() {
super.onStart();
mFirebaseAdapter1 = new FirebaseRecyclerAdapter<ChatModel, ChatMessageViewHolder>(ChatModel.class,
R.layout.textview,
ChatMessageViewHolder.class,
ref_chatchildnode1) {
@Override
protected void populateViewHolder(ChatMessageViewHolder chatMessageViewHolder, ChatModel m, int i) {
chatMessageViewHolder.sender.setText(m.getSender());
chatMessageViewHolder.msg.setText(m.getMessage());
}
};
mRecyclerView.setAdapter(mFirebaseAdapter1);
}
推荐答案
查看第 6 步适用于 Android 的 Firebase 代码实验室,为此使用 AdapterDataObserver
:
mFirebaseAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
@Override
public void onItemRangeInserted(int positionStart, int itemCount) {
super.onItemRangeInserted(positionStart, itemCount);
int friendlyMessageCount = mFirebaseAdapter.getItemCount();
int lastVisiblePosition =
mLinearLayoutManager.findLastCompletelyVisibleItemPosition();
// If the recycler view is initially being loaded or the
// user is at the bottom of the list, scroll to the bottom
// of the list to show the newly added message.
if (lastVisiblePosition == -1 ||
(positionStart >= (friendlyMessageCount - 1) &&
lastVisiblePosition == (positionStart - 1))) {
mMessageRecyclerView.scrollToPosition(positionStart);
}
}
});
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