滑动刷新 recyclerview 重复项目 json

Question

我有一个问题，当我滑动刷新数据时，第一次滑动没问题，但之后每次滑动都重新加载并一遍又一遍地添加相同的数据，到最后我有一个包含相同项目的列表以及...我正在使用装载机。我之前尝试清除，但我不明白我的代码有什么问题，如果有人可以向我解释的话。谢谢你。这是我的代码：

public static final String EXTRA_URL = "imageUrl";
public static final String EXTRA_APKNAME = "apkname";
public static final String EXTRA_APKSIZE = "apksize";
public static final String EXTRA_APKFILE = "apkfile";

private RecyclerView mRecyclerView;
private MyAdapter mExampleAdapter;
private ArrayList<one_item> mExampleList;
private RequestQueue mRequestQueue;
private SwipeRefreshLayout swipeRefreshLayout;


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

    getSupportActionBar().setTitle("APK VIP CHINA");
    getSupportActionBar().setDefaultDisplayHomeAsUpEnabled(true);


    swipeRefreshLayout = findViewById(R.id.refreshlayout);
    mRecyclerView = findViewById(R.id.recycler_view);
    mRecyclerView.setHasFixedSize(true);
    mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
    mExampleList = new ArrayList<>();
    mRequestQueue = Volley.newRequestQueue(this);

    parseJSON();


    swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
        @Override
        public void onRefresh() {
            parseJSON();
            swipeRefreshLayout.setRefreshing(false);

        }
    });


}

private void parseJSON() {

    String url = "http://apkvip.net/json2.php";
    JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, null,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    try {
                        JSONArray jsonArray = response.getJSONArray("data");
                        for (int i = 0; i < jsonArray.length(); i++) {
                            JSONObject hit = jsonArray.getJSONObject(i);
                            String creatorName = hit.getString("ten");
                            String creatorsize = hit.getString("apk_size");
                            String creatorfile = hit.getString("link_apk");
                            String imageUrl = hit.getString("link_img");

                            mExampleList.add(new one_item(imageUrl, creatorName, creatorsize, creatorfile));
                        }
                        mExampleAdapter = new MyAdapter(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);
}

public void onItemClick(int position) {
    Intent detailIntent = new Intent(this, activity_detail.class);
    one_item clickedItem = mExampleList.get(position);
    detailIntent.putExtra(EXTRA_URL, clickedItem.getmImageUrl());
    detailIntent.putExtra(EXTRA_APKNAME, clickedItem.getMapkname());
    detailIntent.putExtra(EXTRA_APKSIZE, clickedItem.getMapksize());
    detailIntent.putExtra(EXTRA_APKFILE, clickedItem.getMapkfile());
    startActivity(detailIntent);
}}

我的适配器：

private ArrayList<one_item> mExampleList;

private OnItemClickListener mListener;
public interface OnItemClickListener {
    void onItemClick(int position);
}
public void setOnItemClickListener(OnItemClickListener listener) {
    mListener = listener;
}


public MyAdapter(Context context, ArrayList<one_item> exampleList) {
    mContext = context;
    mExampleList = exampleList;
}
@Override
public ExampleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View v = LayoutInflater.from(mContext).inflate(R.layout.one_item, parent, false);
    return new ExampleViewHolder(v);
}
@Override
public void onBindViewHolder(ExampleViewHolder holder, int position) {
    one_item currentItem = mExampleList.get(position);
    String imageUrl = currentItem.getmImageUrl();
    String apkname = currentItem.getMapkname();
    String apksize = currentItem.getMapksize();
    String apkfile = currentItem.getMapkfile();

    holder.mTextViewname.setText(apkname);
    holder.mTextViewsize.setText(apksize);
    holder.mTextViewfile.setText(apkfile);

    Picasso.get().load(imageUrl).fit().centerInside().into(holder.mImageView);


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

@Override
public long getItemId(int position) {
    return position;
}

public class ExampleViewHolder extends RecyclerView.ViewHolder {
    public ImageView mImageView;
    public TextView mTextViewname, mTextViewsize, mTextViewfile;

    public ExampleViewHolder(View itemView) {
        super(itemView);
        mImageView = itemView.findViewById(R.id.image);
        mTextViewname = itemView.findViewById(R.id.name);
        mTextViewsize = itemView.findViewById(R.id.size);
        mTextViewfile = itemView.findViewById(R.id.file);

        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);
                    }
                }
            }
        });}}}

我的activitymain.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:background="#FFFFFF"
android:orientation="vertical"
android:padding="5dp">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Recommended Apps"
    android:textColor="#000"
    android:textStyle="bold"
    android:textSize="20sp"
    android:layout_marginBottom="10dp"
    />

<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
    android:id="@+id/refreshlayout"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    >


    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical"
        android:padding="5dp" />

</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

Answer 1

只需在 parseJSON() 函数的第一行使用 mExampleList.clear() 然后您就可以添加“更新的”项目了。

此外，我建议您将 swipeRefreshLayout.setRefreshing(false) 移动到 Volley onResponse 和 onError()[=18 的末尾=] 实施 - 现在你告诉 swipeRefreshLayout 在请求（异步发生）完成之前停止刷新

Answer 2

每次滑动时都在初始化适配器。

更改此 MyAdapter 代码的构造函数。

public MyAdapter(Context context, ArrayList<one_item> exampleList) {
    mContext = context;
    mExampleList = exampleList;
}

到，

public MyAdapter(Context context) {
    mContext = context;
}

public setExampleList(ArrayList<one_item> exampleList){
    mExampleList = exampleList;
}

现在将您的 onCreate 函数更改为。

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

    getSupportActionBar().setTitle("APK VIP CHINA");
    getSupportActionBar().setDefaultDisplayHomeAsUpEnabled(true);


    swipeRefreshLayout = findViewById(R.id.refreshlayout);
    mRecyclerView = findViewById(R.id.recycler_view);
    mRecyclerView.setHasFixedSize(true);
    mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
    mExampleList = new ArrayList<>();
    mRequestQueue = Volley.newRequestQueue(this);

    //Changed Code
    mExampleAdapter = new MyAdapter(MainActivity.this);
    mRecyclerView.setAdapter(mExampleAdapter);
    mExampleAdapter.setOnItemClickListener(MainActivity.this);
    

    parseJSON();


    swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
        @Override
        public void onRefresh() {
            parseJSON();
            swipeRefreshLayout.setRefreshing(false);

        }
    });


}

private void parseJSON() {

    String url = "http://apkvip.net/json2.php";
    JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, null,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    try {
                        JSONArray jsonArray = response.getJSONArray("data");
                        for (int i = 0; i < jsonArray.length(); i++) {
                            JSONObject hit = jsonArray.getJSONObject(i);
                            String creatorName = hit.getString("ten");
                            String creatorsize = hit.getString("apk_size");
                            String creatorfile = hit.getString("link_apk");
                            String imageUrl = hit.getString("link_img");

                            mExampleList.add(new one_item(imageUrl, creatorName, creatorsize, creatorfile));
                        }

                        //Changed Code
                        mExampleAdapter.setExampleList(mExampleList);
                        mExampleAdapter.notifyDataSetChanged();
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            error.printStackTrace();
        }
    });

    mRequestQueue.add(request);
}

我已经在进行更改的代码块中添加了注释。

如有任何疑问，请随时发表评论。

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