java - 自动刷新不起作用，因为我希望它起作用

Question

我有一个名为 ChatActivity 的 Activity ，用户将在其中互相发送消息。该 Activity 在消息发送时检索消息，但当消息显示在此处时，会显示每条消息的重复项。

我确实有自动刷新功能，但它没有按照我希望的方式刷新。在我的 Activity 中也有滑动刷新，当我滑动时它会正确刷新。这是使用滑动刷新时的快照:

如何让自动刷新显示我的消息，就像我滑动刷新时那样？这是我的代码:

public class ChatActivity extends AppCompatActivity {


private Toolbar mChatToolbar; //used
private String mChatUser;  //used
private String mthumb_image;
private String userName;
private String mCurrentUserId;
private TextView mUserStatus;
private EditText mChatMessageView;

private CircleImageView mProfileImage;
private FirebaseAuth mAuth;
private ImageButton mChatAddBtn;

private DatabaseReference mRootRef;
// Storage Firebase
private StorageReference mImageStorage;
private static final int GALLERY_PICK = 1;

private RecyclerView mMessagesList;
private SwipeRefreshLayout mRefreshLayout;

private ArrayList<Messages> arrayList_Messages = new ArrayList<>();

private MessageAdapter mAdapter;

private static final int TOTAL_ITEMS_TO_LOAD = 10;
private int mCurrentPage = 1;

private final Handler handler = new Handler();








@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_chat);


    mChatMessageView = (EditText) findViewById(R.id.chat_message_view);
    mChatAddBtn = (ImageButton) findViewById(R.id.chat_add_btn);

    mChatToolbar = (Toolbar) findViewById(R.id.chat_app_bar);
    setSupportActionBar(mChatToolbar);

    ActionBar actionBar = getSupportActionBar();

    actionBar.setDisplayHomeAsUpEnabled(true);
    actionBar.setDisplayShowCustomEnabled(true);

    //for Custom Action bar
    actionBar.setDisplayShowCustomEnabled(true);

    LayoutInflater inflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
    View customBar = inflater.inflate(R.layout.chat_custom_bar,null);

    actionBar.setCustomView(customBar);

    //getting intent Data
    gettingIntentData();

    // initializing user view
    intCustomBarViewAndSetData();

    doTheAutoRefresh();


    mRootRef = FirebaseDatabase.getInstance().getReference();
    mAuth = FirebaseAuth.getInstance();
    mCurrentUserId =  mAuth.getCurrentUser().getUid();



    //------- IMAGE STORAGE ---------
    mImageStorage = FirebaseStorage.getInstance().getReference();

    mRootRef.child("Chat").child(mCurrentUserId).child(mChatUser).child("seen").setValue(true);


    LoadMessages();

    //getting information about user online or offline and thumb image
    mRootRef.child("Users").child(mChatUser).addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            String thumb_image = dataSnapshot.child("thumb_image").getValue().toString();
            Picasso.with(ChatActivity.this).load(thumb_image).placeholder(R.drawable.my_profile).into(mProfileImage);

            String lastSeen = dataSnapshot.child("online").getValue().toString();

            if(lastSeen.equals("true")){
                mUserStatus.setText("Online");
            }
            else{

                //converting string into long
                Long lastTime = Long.parseLong(lastSeen);

                // creating an instance of GetTimeAgo class
                GetTimeAgo getTimeAgo = new GetTimeAgo();
                String lastSeenTime = GetTimeAgo.getTimeAgo(lastTime,getApplicationContext());
                mUserStatus.setText(lastSeenTime);
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });


    //for creating chat object
    mRootRef.child("Chat").child(mCurrentUserId).addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            if(!dataSnapshot.hasChild(mChatUser)){

                Map chatAddMap = new HashMap();
                chatAddMap.put("seen",false);
                chatAddMap.put("timestamp", ServerValue.TIMESTAMP);

                Map chatUserMap = new HashMap();
                chatUserMap.put("Chat/"+mCurrentUserId+"/"+mChatUser, chatAddMap);
                chatUserMap.put("Chat/"+mChatUser+"/"+mCurrentUserId, chatAddMap);

                mRootRef.updateChildren(chatUserMap, new DatabaseReference.CompletionListener() {
                    @Override
                    public void onComplete(DatabaseError databaseError, DatabaseReference databaseReference) {

                        if(databaseError!= null){
                            Toast.makeText(ChatActivity.this, "Error: "+databaseError.getMessage(), Toast.LENGTH_SHORT).show();

                        }
                    }
                });
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });


    // Retrieving the chat messages into recyclerview
    LoadMessages();
    mRefreshLayout.setRefreshing(true);
    mRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
        @Override
        public void onRefresh() {

            mCurrentPage++;

            //onRefresh remove the current messages from arraylist and load new messages
            arrayList_Messages.clear();

            // Load message
            LoadMessages();


        }
    });


}

private void doTheAutoRefresh()
{
    handler.postDelayed(new Runnable() {
        @Override
        public void run()
        {
            LoadMessages();
            // Write code for your refresh logic
            doTheAutoRefresh();
        }
    }, 5000);
}

// Load all messages from database into recyclerView
private void LoadMessages() {

    DatabaseReference messageRef = mRootRef.child("messages").child(mCurrentUserId).child(mChatUser);

    //Query to load message per page i.e. 10
    /*
       per page load 10 message and onRefresh mCurrentpage is increment by 1
       page 1 => load 10 messages (mCurrentPage = 1 then 1*10 =10)
       page 2 => load 20 messages (mCurrentPage = 2 then 2*10 =20) and so on
     */

    Query messageQuery = messageRef.limitToLast(mCurrentPage * TOTAL_ITEMS_TO_LOAD);

    messageQuery.addChildEventListener(new ChildEventListener() {
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {

            Messages messages = dataSnapshot.getValue(Messages.class);
            arrayList_Messages.add(messages);
            mRefreshLayout.setRefreshing(true);
            mAdapter.notifyDataSetChanged();

            mMessagesList.scrollToPosition(arrayList_Messages.size()-1);

            //when data load completely set refreshing
            mRefreshLayout.setRefreshing(false);
        }

        @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(DatabaseError databaseError) {

        }
    });
}


// send button
public void chatSendButton(View view){

    sendMessage();
}

//sending a message
private void sendMessage() {

    String message = mChatMessageView.getText().toString().trim();

    if(!TextUtils.isEmpty(message)){

        mChatMessageView.setText("");
        String current_user_ref="messages/"+mCurrentUserId+"/"+mChatUser;
        String chat_user_ref= "messages/"+mChatUser+"/"+mCurrentUserId;

        DatabaseReference chat_push_key = mRootRef.child("messages").child(mCurrentUserId).
                child(mChatUser).push();

        String push_key = chat_push_key.getKey();

        Map messageMap = new HashMap();
        messageMap.put("message",message);
        messageMap.put("type","text");
        messageMap.put("from",mCurrentUserId);
        messageMap.put("seen",false);
        messageMap.put("time", ServerValue.TIMESTAMP);

        Map messageUserMap = new HashMap();
        messageUserMap.put(current_user_ref+ "/"+push_key,messageMap);
        messageUserMap.put(chat_user_ref+ "/"+push_key,messageMap);

        mRootRef.updateChildren(messageUserMap, new DatabaseReference.CompletionListener() {
            @Override
            public void onComplete(DatabaseError databaseError, DatabaseReference databaseReference) {

                if(databaseError!=null){
                    Log.d("TAG",databaseError.getMessage().toString());
                }
            }
        });
    }
}

//add button
public void chatAddButton(View view){
    mChatAddBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent galleryIntent = new Intent();
            galleryIntent.setType("image/*");
            galleryIntent.setAction(Intent.ACTION_GET_CONTENT);

            startActivityForResult(Intent.createChooser(galleryIntent, "SELECT IMAGE"), GALLERY_PICK);
        }
    });


}

@Override
protected void onResume() {
    super.onResume();


}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if(requestCode == GALLERY_PICK && resultCode == RESULT_OK){

        Uri imageUri = data.getData();

        final String current_user_ref = "messages/" + mCurrentUserId + "/" + mChatUser;
        final String chat_user_ref = "messages/" + mChatUser + "/" + mCurrentUserId;

        DatabaseReference user_message_push = mRootRef.child("messages")
                .child(mCurrentUserId).child(mChatUser).push();

        final String push_id = user_message_push.getKey();


        StorageReference filepath = mImageStorage.child("message_images").child( push_id + ".jpg");

        filepath.putFile(imageUri).addOnCompleteListener(new OnCompleteListener<UploadTask.TaskSnapshot>() {
            @Override
            public void onComplete(@NonNull Task<UploadTask.TaskSnapshot> task) {

                if(task.isSuccessful()){

                    String download_url = task.getResult().getDownloadUrl().toString();


                    Map messageMap = new HashMap();
                    messageMap.put("message", download_url);
                    messageMap.put("seen", false);
                    messageMap.put("type", "image");
                    messageMap.put("time", ServerValue.TIMESTAMP);
                    messageMap.put("from", mCurrentUserId);

                    Map messageUserMap = new HashMap();
                    messageUserMap.put(current_user_ref + "/" + push_id, messageMap);
                    messageUserMap.put(chat_user_ref + "/" + push_id, messageMap);

                    mChatMessageView.setText("");

                    mRootRef.updateChildren(messageUserMap, new DatabaseReference.CompletionListener() {
                        @Override
                        public void onComplete(DatabaseError databaseError, DatabaseReference databaseReference) {

                            if(databaseError != null){

                                Log.d("CHAT_LOG", databaseError.getMessage().toString());

                            }

                        }
                    });


                }

            }
        });

    }

}


private void intCustomBarViewAndSetData() {
    TextView mTitleView = (TextView) findViewById(R.id.custom_bar_title);
    mUserStatus = (TextView) findViewById(R.id.custom_bar_seen);
    mProfileImage = (CircleImageView) findViewById(R.id.custom_bar_image);
    mMessagesList = (RecyclerView) findViewById(R.id.messages_list);

    mMessagesList.setLayoutManager(new LinearLayoutManager(this));
    mRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.message_swipe_layout);
    mMessagesList.setHasFixedSize(true);

    mAdapter = new MessageAdapter(this, arrayList_Messages);
    mMessagesList.setAdapter(mAdapter);

    //showing name on toolbar
    mTitleView.setText(userName);
    mTitleView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent profileIntent = new Intent(ChatActivity.this, ProfileActivity.class);
            profileIntent.putExtra("user_id", mChatUser);
            startActivity(profileIntent);
        }
    });




}

private void gettingIntentData() {
    Intent intent =getIntent();
    userName = intent.getStringExtra("Username");
    mChatUser = intent.getStringExtra("user_id");
}
}

Answer 1

在 doTheAutoRefresh() 中加载之前清除列表。

arrayList_Messages.clear();
LoadMessages();