如何在RecyclerView中添加刷新滑动

Question

我有新闻应用程序，它从jsonurl提供新闻帖子，我想添加刷新滑动来获取新闻帖子。当我刷新布局时，如何将其添加到我的MainActivity和下面的类中：

public class MainActivity extends AppCompatActivity implements ExampleAdapter.OnItemClickListener {
public static final String EXTRA_URL = "imageUrl";
public static final String EXTRA_CREATOR = "creatorName";

private RecyclerView mRecyclerView;
private ExampleAdapter mExampleAdapter;
private ArrayList<ExampleItem> mExampleList;
private RequestQueue mRequestQueue;
String API_KEY = "850e0efe6adf4eb38afefa14d33e4b48"; // ### YOUE NEWS API HERE ###
String NEWS_SOURCE = "bbc-news";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRecyclerView = findViewById(R.id.recycler_view);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
mExampleList = new ArrayList<>();
mRequestQueue = Volley.newRequestQueue(this);
parseJSON();
}
private void parseJSON() {
String url = "http://newsapi.org/v1/articles?source="+NEWS_SOURCE+"&sortBy=top&apiKey="+API_KEY;
JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, null,
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
JSONArray jsonArray = response.optJSONArray("articles");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject hit = jsonArray.getJSONObject(i);
String creatorName = hit.getString("title");
String imageUrl = hit.getString("urlToImage");

mExampleList.add(new ExampleItem(imageUrl, creatorName));
}
mExampleAdapter = new ExampleAdapter(MainActivity.this, mExampleList);
mRecyclerView.setAdapter(mExampleAdapter);
mExampleAdapter.setOnItemClickListener(MainActivity.this);
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
});
mRequestQueue.add(request);
}
@Override
public void onItemClick(int position) {
Intent detailIntent = new Intent(this, DetailActivity.class);
ExampleItem clickedItem = mExampleList.get(position);
detailIntent.putExtra(EXTRA_URL, clickedItem.getImageUrl());
detailIntent.putExtra(EXTRA_CREATOR, clickedItem.getCreator());
startActivity(detailIntent);
}
}

示例适配器.java

public class ExampleAdapter extends RecyclerView.Adapter<ExampleAdapter.ExampleViewHolder> {
private Context mContext;
private ArrayList<ExampleItem> mExampleList;
private OnItemClickListener mListener;
public interface OnItemClickListener {
void onItemClick(int position);
}
public void setOnItemClickListener(OnItemClickListener listener) {
mListener = listener;
}
public ExampleAdapter(Context context, ArrayList<ExampleItem> exampleList) {
mContext = context;
mExampleList = exampleList;
}
@Override
public ExampleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(mContext).inflate(R.layout.example_item, parent, false);
return new ExampleViewHolder(v);
}
@Override
public void onBindViewHolder(ExampleViewHolder holder, int position) {
ExampleItem currentItem = mExampleList.get(position);
String imageUrl = currentItem.getImageUrl();
String creatorName = currentItem.getCreator();

holder.mTextViewCreator.setText(creatorName);
Picasso.with(mContext).load(imageUrl).fit().centerInside().into(holder.mImageView);
}
@Override
public int getItemCount() {
return mExampleList.size();
}
public class ExampleViewHolder extends RecyclerView.ViewHolder {
public ImageView mImageView;
public TextView mTextViewCreator;
public TextView mTextViewLikes;
public ExampleViewHolder(View itemView) {
super(itemView);
mImageView = itemView.findViewById(R.id.image_view);
mTextViewCreator = itemView.findViewById(R.id.text_view_creator);
mTextViewLikes = itemView.findViewById(R.id.text_view_likes);
itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mListener != null) {
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION) {
mListener.onItemClick(position);
}
}
}
});
}
}
}

示例项.java

public class ExampleItem {
private String mImageUrl;
private String mCreator;
public ExampleItem(String imageUrl, String creator) {
mImageUrl = imageUrl;
mCreator = creator;
}
public String getImageUrl() {
return mImageUrl;
}
public String getCreator() {
return mCreator;
}
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="recylerviewjsonexample.codinginflow.com
.recylerviewjsonexample.MainActivity">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/darker_gray" />

示例_item.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="8dp"
app:cardCornerRadius="8dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="16dp">
<ImageView
android:id="@+id/image_view"
android:layout_width="match_parent"
android:layout_height="200dp"
android:src="@mipmap/ic_launcher" />
<TextView
android:id="@+id/text_view_creator"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Creator Name"
android:textColor="@android:color/black"
android:textSize="20sp" />
<TextView
android:id="@+id/text_view_likes"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Like: " />
</LinearLayout>
</android.support.v7.widget.CardView>

Answer 1

在您的XML文件中

<android.support.v4.widget.SwipeRefreshLayout
android:id="@+id/refreshLayout"
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.support.v4.widget.SwipeRefreshLayout>

在java类中，您将清除旧列表，然后再次调用API方法

binding.refreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
if (data_list != null) {
data_list.clear();
}
CallyourMethod();
binding.refreshLayout.setRefreshing(false);
}
});

Answer 2

您可以在RecyclerView周围放置SwipeRefreshLayout作为：

<android.support.v4.widget.SwipeRefreshLayout
android:id="@+id/swipeRefreshLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/darker_gray" />
</android.support.v4.widget.SwipeRefreshLayout>

在MainActivity.java的onCreateMethod((中添加

swipeRefreshLayout.setEnabled(true(；

要在滑动列表刷新时显示加载程序，您可以添加：swipeRefreshLayout.setProgressViewEndTarget(true，SWIPE_REFRESH_LAYOUT_OFFSET(；

SwipeRefreshLayout在滑动列表以执行必要的操作时提供回调

swipeRefreshLayout.setOnRefreshListener(new OnRefreshListener() {
@Override
public void onRefresh() {
//perform your action here
}
});