那些遇到过的问题

如何在一个活动中将addOnScrollListener与不同的列表一起使用

Dr *_*ido 14 java android onscrolllistener android-recyclerview retrofit2

在我的应用程序中,有两种方法getData和getItemsByLabel.每个人都得到不同的列表,我使用了导航抽屉方法,onNavigationItemSelected这样每当用户点击某个特定项目时,就会显示一个不同的列表RecyclerView.问题是我使用一种方法addOnScrollListener来检测任何列表中的滚动行为RecyclerView,导致项目在显示的列表中重叠.

因此问题在于当向下滚动时,主列表中的项目和所选类别/项目的列表是重叠的.

这是我的代码.

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

    Fabric.with(this, new Crashlytics());

    // Crashlytics.logException(new Exception("My first Android non-fatal error"));
    // I'm also creating a log message, which we'll look at in more detail later
    // Crashlytics.log("MainActivity started");

    swipeRefreshLayout = findViewById(R.id.swipeRefreshLayout);
    recyclerView = findViewById(R.id.recyclerView);
    manager = new LinearLayoutManager(this);
    emptyView = (TextView) findViewById(R.id.empty_view);
    progressBar = findViewById(R.id.spin_kit);
    adapter = new PostAdapter(this, items);
    recyclerView.setLayoutManager(manager);
    recyclerView.setAdapter(adapter);
    toolbar = findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    getSupportActionBar().setDisplayShowTitleEnabled(false);
    toolbar.setTitle(R.string.home);

    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.addDrawerListener(toggle);
    toggle.syncState();
    NavigationView navigationView = findViewById(R.id.nav_view);
    navigationView.getMenu().getItem(0).setChecked(true);
    navigationView.setNavigationItemSelectedListener(this);
    swipeRefreshLayout.setColorSchemeColors(getResources().getColor(R.color.colorPrimaryGreen));
    swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
        @Override
        public void onRefresh() {
            if (navigationView.getMenu().getItem(0).isChecked()) {
                if (Utils.hasNetworkAccess(MainActivity.this)) {
                    getData();
                } else {
                    Toast.makeText
                            (MainActivity.this, "You must connect to the Internet to update the list"
                                    , Toast.LENGTH_LONG).show();
                }
            } else {
                for (int i = 1; i < 7; i++) {
                    if (navigationView.getMenu().getItem(i).isChecked()) {
                        getItemsByLabel(navigationView.getMenu().getItem(i).getTitle().toString());
                    }
                }
            }

            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    swipeRefreshLayout.setRefreshing(false);
                }
            }, 3000);
        }

    });

    recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
            super.onScrollStateChanged(recyclerView, newState);
            if (newState == AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL) {
                isScrolling = true;
                if (!recyclerView.canScrollVertically(1)) {
                    progressBar.setVisibility(View.GONE);
                }
            }
        }

        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);
            if (dy > 0) {
                currentItems = manager.getChildCount();
                totalItems = manager.getItemCount();
                scrollOutItems = manager.findFirstVisibleItemPosition();
                if (isScrolling && (currentItems + scrollOutItems == totalItems)) {
                    isScrolling = false;
                    getData(); // This is where I call getData <--
                }
            }
        }
    });

    if (Utils.hasNetworkAccess(this)) {
        getData();
    } else {
        if (runtimeExceptionDaoItems == null || runtimeExceptionDaoItems.queryForAll().isEmpty()) {
            Toast.makeText(this, "There's no data", Toast.LENGTH_LONG).show();
        } else {
            items.addAll(runtimeExceptionDaoItems.queryForAll());
            Toast.makeText(this, "From Database", Toast.LENGTH_LONG).show();
        }
    }
}

long lastPress;
Toast backpressToast;

@Override
public void onBackPressed() {
    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        long currentTime = System.currentTimeMillis();
        if (currentTime - lastPress > 5000) {
            backpressToast = Toast.makeText(getBaseContext(), "Press back again to exit", Toast.LENGTH_LONG);
            backpressToast.show();
            lastPress = currentTime;
        } else {
            if (backpressToast != null) backpressToast.cancel();
            super.onBackPressed();
        }
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    SearchManager searchManager = (SearchManager) getSystemService(SEARCH_SERVICE);
    SearchView searchView = (SearchView) menu.findItem(R.id.app_bar_search).getActionView();
    searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));
    searchView.setQueryHint(getResources().getString(R.string.searchForPosts));
    searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
        @Override
        public boolean onQueryTextSubmit(String keyword) {
            getItemsBySearch(keyword);
            return false;
        }

        @Override
        public boolean onQueryTextChange(String keyword) {
            return false;
        }
    });

    searchView.setOnCloseListener(() -> {
        emptyView.setVisibility(View.GONE);
        recyclerView.setVisibility(View.VISIBLE);
        getData();
        return false;
    });

    return true;
}

@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
    // Handle navigation view item clicks here.

    switch (item.getItemId()) {
        case R.id.home:
            getData();
            break;
        case R.id.accessory:
            toolbar.setTitle(R.string.accessory);
            getItemsByLabel("Accessory");
            break;
        case R.id.arcade:
            toolbar.setTitle(R.string.arcade);
            getItemsByLabel("Arcade");
            break;
        case R.id.fashion:
            toolbar.setTitle(R.string.fashion);
            getItemsByLabel("Fashion");
            break;
        case R.id.food:
            toolbar.setTitle(R.string.food);
            getItemsByLabel("Food");
            break;
        case R.id.heath:
            toolbar.setTitle(R.string.heath);
            getItemsByLabel("Heath");
            break;
        case R.id.lifeStyle:
            toolbar.setTitle(R.string.lifestyle);
            getItemsByLabel("Lifestyle");
            break;
        case R.id.sports:
            toolbar.setTitle(R.string.sports);
            getItemsByLabel("Sports");
            break;
        case R.id.settings:
            break;
    }

    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;
}

private void getData() {
    progressBar.setVisibility(View.VISIBLE);
    String url = BloggerAPI.BASE_URL + "?key=" + BloggerAPI.KEY;

    if (token != "") {
        url = url + "&pageToken=" + token;
    }
    if (token == null) {
        return;
    }

    final Call<PostList> postList = BloggerAPI.getService().getPostList(url);
    postList.enqueue(new Callback<PostList>() {
        @Override
        public void onResponse(@NonNull Call<PostList> call, @NonNull Response<PostList> response) {
            if (response.isSuccessful()) {
                progressBar.setVisibility(View.GONE);
                PostList list = response.body();
                if (list != null) {
                    token = list.getNextPageToken();
                    items.addAll(list.getItems());
                    adapter.notifyDataSetChanged();
            } else {
                progressBar.setVisibility(View.GONE);
                recyclerView.setVisibility(View.GONE);
                emptyView.setVisibility(View.VISIBLE);

                int sc = response.code();
                switch (sc) {
                    case 400:
                        Log.e("Error 400", "Bad Request");
                        break;
                    case 404:
                        Log.e("Error 404", "Not Found");
                        break;
                    default:
                        Log.e("Error", "Generic Error");
                }
            }
        }

        @Override
        public void onFailure(@NonNull Call<PostList> call, @NonNull Throwable t) {
            Toast.makeText(MainActivity.this, "Error occured", Toast.LENGTH_LONG).show();
            Log.e(TAG, "onFailure: " + t.toString());
            Log.e(TAG, "onFailure: " + t.getCause());
            progressBar.setVisibility(View.GONE);
            recyclerView.setVisibility(View.GONE);
            emptyView.setVisibility(View.VISIBLE);
        }
    });
}

//=============================================================================================

public void getItemsByLabel(String label) {
    progressBar.setVisibility(View.VISIBLE);
    String url = BloggerAPI.BASE_URL + "search?q=label:" + label + "&key=" + BloggerAPI.KEY;

    Log.e("Label :", url);

    if (token != "") {
        url = url + "&pageToken=" + token;
    }
    if (token == null) {
        return;
    }

    final Call<PostList> postList = BloggerAPI.getService().getPostList(url);
    postList.enqueue(new Callback<PostList>() {
        @Override
        public void onResponse(@NonNull Call<PostList> call, @NonNull Response<PostList> response) {
            if (response.isSuccessful()) {
                progressBar.setVisibility(View.GONE);
                items.clear();
                recyclerView.swapAdapter(adapter, false);
                PostList list = response.body();
                if (list != null) {
                    token = list.getNextPageToken();
                    items.addAll(list.getItems());
                    adapter.notifyDataSetChanged();
                }
            } else {
                progressBar.setVisibility(View.GONE);
                recyclerView.setVisibility(View.GONE);
                emptyView.setVisibility(View.VISIBLE);
                int sc = response.code();
                switch (sc) {
                    case 400:
                        Log.e("Error 400", "Bad Request");
                        break;
                    case 404:
                        Log.e("Error 404", "Not Found");
                        break;
                    default:
                        Log.e("Error", "Generic Error");
                }
            }
        }

        @Override
        public void onFailure(@NonNull Call<PostList> call, @NonNull Throwable t) {
            Toast.makeText(MainActivity.this, "Error occured", Toast.LENGTH_LONG).show();
            Log.e(TAG, "onFailure: " + t.toString());
            Log.e(TAG, "onFailure: " + t.getCause());
            progressBar.setVisibility(View.GONE);
            recyclerView.setVisibility(View.GONE);
            emptyView.setVisibility(View.VISIBLE);
        }
    });
}
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我试图解决这个问题的方法:

  1. ScrollListener在每个方法中实现getData和getItemsByLabel
  2. 为导航抽屉菜单上的每个项目创建一个片段并ScrollListener在其上实现.
  3. 最后,我在循环onScrolled方法上检测抽屉菜单上的哪个项目被检查以获得它自己的列表.但不幸的是,没有一个工作.

und*_*oid 0

我认为问题的发生是因为recyclerView.swapAdapter(adapter, false);

swapAdapter 用于将适配器更换为新适配器。您传递相同的适配器，因此此调用毫无用处。即使你想设置一个新的适配器，布尔参数也应该为true，让RecyclerView回收所有现有的View。

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