来自android开发者(创建列表和卡片):

RecyclerView小部件是一个更高级和灵活的版本 列表视图。

好吧，这听起来很酷，但当我看到这张示例图片时，我真的很困惑这两者之间的区别。

上面的图片可以通过ListView使用自定义适配器轻松创建。

那么，在什么情况下应该使用RecyclerView呢?

我发现这些方法背后的概念和意义有点令人困惑，有人能在一个例子中(如果可能的话)向我解释一下has和with is之间的区别吗?

我理解事件的目的，特别是在创建用户界面的上下文中。我认为这是创建事件的原型:

public void EventName(object sender, EventArgs e);

事件处理程序做什么，为什么需要它们，以及如何创建一个?

我试图实现从支持库的SearchView。我想让用户使用SearchView来过滤一个RecyclerView中的电影列表。

到目前为止，我已经遵循了一些教程，我已经添加了搜索视图到动作栏，但我真的不确定从这里去哪里。我看过一些例子，但没有一个在你开始输入时显示结果。

这是MainActivity:

public class MainActivity extends ActionBarActivity {

    RecyclerView mRecyclerView;
    RecyclerView.LayoutManager mLayoutManager;
    RecyclerView.Adapter mAdapter;

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

        mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        mRecyclerView.setHasFixedSize(true);

        mLayoutManager = new LinearLayoutManager(this);
        mRecyclerView.setLayoutManager(mLayoutManager);

        mAdapter = new CardAdapter() {
            @Override
            public Filter getFilter() {
                return null;
            }
        };
        mRecyclerView.setAdapter(mAdapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
        SearchView searchView = (SearchView) menu.findItem(R.id.menu_search).getActionView();
        searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

这是我的适配器:

public abstract class CardAdapter extends RecyclerView.Adapter<CardAdapter.ViewHolder> implements Filterable {

    List<Movie> mItems;

    public CardAdapter() {
        super();
        mItems = new ArrayList<Movie>();
        Movie movie = new Movie();
        movie.setName("Spiderman");
        movie.setRating("92");
        mItems.add(movie);

        movie = new Movie();
        movie.setName("Doom 3");
        movie.setRating("91");
        mItems.add(movie);

        movie = new Movie();
        movie.setName("Transformers");
        movie.setRating("88");
        mItems.add(movie);

        movie = new Movie();
        movie.setName("Transformers 2");
        movie.setRating("87");
        mItems.add(movie);

        movie = new Movie();
        movie.setName("Transformers 3");
        movie.setRating("86");
        mItems.add(movie);

        movie = new Movie();
        movie.setName("Noah");
        movie.setRating("86");
        mItems.add(movie);

        movie = new Movie();
        movie.setName("Ironman");
        movie.setRating("86");
        mItems.add(movie);

        movie = new Movie();
        movie.setName("Ironman 2");
        movie.setRating("86");
        mItems.add(movie);

        movie = new Movie();
        movie.setName("Ironman 3");
        movie.setRating("86");
        mItems.add(movie);
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.recycler_view_card_item, viewGroup, false);
        return new ViewHolder(v);
    }

    @Override
    public void onBindViewHolder(ViewHolder viewHolder, int i) {
        Movie movie = mItems.get(i);
        viewHolder.tvMovie.setText(movie.getName());
        viewHolder.tvMovieRating.setText(movie.getRating());
    }

    @Override
    public int getItemCount() {
        return mItems.size();
    }

    class ViewHolder extends RecyclerView.ViewHolder{

        public TextView tvMovie;
        public TextView tvMovieRating;

        public ViewHolder(View itemView) {
            super(itemView);
            tvMovie = (TextView)itemView.findViewById(R.id.movieName);
            tvMovieRating = (TextView)itemView.findViewById(R.id.movieRating);
        }
    }
}

我有一个值，我想存储这个值和一个引用 在我自己类型的价值中:

struct Thing {
    count: u32,
}

struct Combined<'a>(Thing, &'a u32);

fn make_combined<'a>() -> Combined<'a> {
    let thing = Thing { count: 42 };

    Combined(thing, &thing.count)
}

有时，我有一个值，我想存储这个值和它的引用 相同结构中的值:

struct Combined<'a>(Thing, &'a Thing);

fn make_combined<'a>() -> Combined<'a> {
    let thing = Thing::new();

    Combined(thing, &thing)
}

有时，我甚至不取值的参考，我得到 同样的错误:

struct Combined<'a>(Parent, Child<'a>);

fn make_combined<'a>() -> Combined<'a> {
    let parent = Parent::new();
    let child = parent.child();

    Combined(parent, child)
}

在每一种情况下，我都会得到一个值“does”的错误 活得不够长”。这个错误意味着什么?

我想把ListView改为RecyclerView。我想在RecyclerView中使用OnScrollListener的onScroll来确定用户是否滚动到列表的末尾。

我如何知道用户是否滚动到列表的末尾以便我可以从REST服务获取新数据?

我试图弄清楚更新RecyclerView的适配器有什么问题。

在我得到一个新的产品清单后，我试着:

Update the ArrayList from the fragment where recyclerView is created, set new data to adapter, and then call adapter.notifyDataSetChanged(); it did not work. Create a new adapter, as others did, and it worked for them, but there wasn't any change for me: recyclerView.setAdapter(new RecyclerViewAdapter(newArrayList)) Create a method in Adapter which updates the data as follows: public void updateData(ArrayList<ViewModel> viewModels) { items.clear(); items.addAll(viewModels); notifyDataSetChanged(); } Then I call this method whenever I want to update the data list; it did not work. To check if I can modify the recyclerView in any way, and I tried to remove at least an item: public void removeItem(int position) { items.remove(position); notifyItemRemoved(position); }

一切都保持原样。

这是我的适配器:

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> implements View.OnClickListener {

    private ArrayList<ViewModel> items;
    private OnItemClickListener onItemClickListener;

    public RecyclerViewAdapter(ArrayList<ViewModel> items) {
        this.items = items;
    }


    public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
        this.onItemClickListener = onItemClickListener;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_recycler, parent, false);
        v.setOnClickListener(this);
        return new ViewHolder(v);
    }

    public void updateData(ArrayList<ViewModel> viewModels) {
        items.clear();
        items.addAll(viewModels);
        notifyDataSetChanged();
    }
    public void addItem(int position, ViewModel viewModel) {
        items.add(position, viewModel);
        notifyItemInserted(position);
    }

    public void removeItem(int position) {
        items.remove(position);
        notifyItemRemoved(position);
    }


    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        ViewModel item = items.get(position);
        holder.title.setText(item.getTitle());
        Picasso.with(holder.image.getContext()).load(item.getImage()).into(holder.image);
        holder.price.setText(item.getPrice());
        holder.credit.setText(item.getCredit());
        holder.description.setText(item.getDescription());

        holder.itemView.setTag(item);
    }


    @Override
    public int getItemCount() {
        return items.size();
    }


    @Override
    public void onClick(final View v) {
        // Give some time to the ripple to finish the effect
        if (onItemClickListener != null) {
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    onItemClickListener.onItemClick(v, (ViewModel) v.getTag());
                }
            }, 0);
        }
    }

    protected static class ViewHolder extends RecyclerView.ViewHolder {
        public ImageView image;
        public TextView price, credit, title, description;

        public ViewHolder(View itemView) {
            super(itemView);
            image = (ImageView) itemView.findViewById(R.id.image);
            price = (TextView) itemView.findViewById(R.id.price);
            credit = (TextView) itemView.findViewById(R.id.credit);
            title = (TextView) itemView.findViewById(R.id.title);
            description = (TextView) itemView.findViewById(R.id.description);
        }
    }

    public interface OnItemClickListener {

        void onItemClick(View view, ViewModel viewModel);

    }
}

我启动RecyclerView，如下所示:

recyclerView = (RecyclerView) view.findViewById(R.id.recycler);
recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), 5));
adapter = new RecyclerViewAdapter(items);
adapter.setOnItemClickListener(this);
recyclerView.setAdapter(adapter);

那么，如何实际更新适配器数据以显示新接收到的项呢?

---

问题是gridView的布局是这样的:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:tag="catalog_fragment"
    android:layout_height="match_parent">

    <FrameLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recycler"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:clipToPadding="false"/>

        <ImageButton
            android:id="@+id/fab"
            android:layout_gravity="top|end"
            style="@style/FabStyle"/>

    </FrameLayout>
</LinearLayout>

然后我只是删除线性布局，并使FrameLayout作为父布局。

a can only be final here. Why? How can I reassign a in onClick() method without keeping it as private member? private void f(Button b, final int a){ b.addClickHandler(new ClickHandler() { @Override public void onClick(ClickEvent event) { int b = a*5; } }); } How can I return the 5 * a when it clicked? I mean, private void f(Button b, final int a){ b.addClickHandler(new ClickHandler() { @Override public void onClick(ClickEvent event) { int b = a*5; return b; // but return type is void } }); }

我需要在我的Android应用程序中实现一个水平列表视图。我做了一些研究，遇到了如何在Android中创建一个水平的ListView ?和横向列表视图在Android?然而，这些问题是在Recyclerview发布之前提出的。有没有更好的方法来实现这个现在与Recyclerview?

我使用ng-view来包括AngularJS的部分视图，我想根据所包含的视图更新页面标题和h1头标签。这些超出了局部视图控制器的范围，所以我不知道如何将它们绑定到控制器中的数据集。

如果是ASP。NET MVC，你可以使用@ViewBag来做这个，但我不知道在AngularJS中等价的。我已经搜索了共享服务，事件等，但仍然不能让它工作。任何方式修改我的例子，使其工作将非常感激。

我的HTML:

<html data-ng-app="myModule">
<head>
<!-- include js files -->
<title><!-- should changed when ng-view changes --></title>
</head>
<body>
<h1><!-- should changed when ng-view changes --></h1>

<div data-ng-view></div>

</body>
</html>

我的JavaScript:

var myModule = angular.module('myModule', []);
myModule.config(['$routeProvider', function($routeProvider) {
    $routeProvider.
        when('/test1', {templateUrl: 'test1.html', controller: Test1Ctrl}).
        when('/test2', {templateUrl: 'test2.html', controller: Test2Ctrl}).
        otherwise({redirectTo: '/test1'});
}]);

function Test1Ctrl($scope, $http) { $scope.header = "Test 1"; 
                                  /* ^ how can I put this in title and h1 */ }
function Test2Ctrl($scope, $http) { $scope.header = "Test 2"; }