android - 未注释的参数覆盖@NonNull 参数

Question

@nonnull inflater 错误，谁能解决这个错误？我是 android 的新手，我不知道如何解决这个错误的任何解决方案？是主题错误还是其他原因，我的代码有什么大问题吗？？你能解决这个错误吗？由于此错误，我的代码无法正常工作。非常感谢您的帮助

下面列出了我在代码中的导入

       import android.content.Context;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.app.DownloadManager;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.support.annotation.Nullable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.support.v7.widget.DividerItemDecoration;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
import java.util.List;
import android.support.annotation.Nullable;
import android.util.Log;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import android.widget.ImageButton;
import android.widget.ProgressBar;
import static android.content.Context.DOWNLOAD_SERVICE;
import java.lang.reflect.Type;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;
import java.lang.ref.WeakReference;
import java.lang.reflect.Type;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;



 public class FilesListingFragment extends android.support.v4.app.Fragment {


    private static final String TAG = "FilesListingFragment";

    public static final String PATH_FILES = "http://%s:%s/files";
    public static final String PATH_STATUS = "http://%s:%s/status";
    public static final String PATH_FILE_DOWNLOAD = "http://%s:%s/file/%s";

    private String mSenderIp = null, mSenderSSID;
    private ContactSenderAPITask mUrlsTask;
    private ContactSenderAPITask mStatusCheckTask;

    private String mPort, mSenderName;

    static final int CHECK_SENDER_STATUS = 100;
    static final int SENDER_DATA_FETCH = 101;

    RecyclerView file;
    ProgressBar progressBar;
    TextView mTextView;

    private SenderFilesListingAdapter mFilesAdapter;

    private UiUpdateHandler uiUpdateHandler;

    private static final int SENDER_DATA_FETCH_RETRY_LIMIT = 3;
    private int senderDownloadsFetchRetry = SENDER_DATA_FETCH_RETRY_LIMIT, senderStatusCheckRetryLimit = SENDER_DATA_FETCH_RETRY_LIMIT;

    @Nullable

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment_files_listing, null);
        file = (RecyclerView) v.findViewById(R.id.files_list);
        progressBar = (ProgressBar) v.findViewById(R.id.loading);
        mTextView = (TextView) v.findViewById(R.id.empty_listing_text);
        mTextView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                mTextView.setVisibility(View.GONE);
                progressBar.setVisibility(View.VISIBLE);
                fetchSenderFiles();
            }
        });
        file.setLayoutManager(new LinearLayoutManager(getActivity()));
        file.addItemDecoration(new DividerItemDecoration(getResources().getDrawable(R.drawable.lidivider)));/**here is the error */
        mFilesAdapter = new SenderFilesListingAdapter(new ArrayList<String>());
        file.setAdapter(mFilesAdapter);
        uiUpdateHandler = new UiUpdateHandler(this);
        return v;
    }

    public static FilesListingFragment getInstance(String senderIp, String ssid, String senderName, String port) {
        FilesListingFragment fragment = new FilesListingFragment();
        Bundle data = new Bundle();
        data.putString("senderIp", senderIp);
        data.putString("ssid", ssid);
        data.putString("name", senderName);
        data.putString("port", port);
        fragment.setArguments(data);
        return fragment;
    }

    @Override
    public void onAttach(Context activity) {
        super.onAttach(activity);
        if (null != getArguments()) {
            mSenderIp = getArguments().getString("senderIp");
            mSenderSSID = getArguments().getString("ssid");
            mPort = getArguments().getString("port");
            mSenderName = getArguments().getString("name");
            Log.d(TAG, "sender ip: " + mSenderIp);
        }
    }

    @Override
    public void onResume() {
        super.onResume();
        fetchSenderFiles();
        checkSenderAPIAvailablity();
    }

    private void fetchSenderFiles() {
        progressBar.setVisibility(View.VISIBLE);
        if (null != mUrlsTask)
            mUrlsTask.cancel(true);
        mUrlsTask = new ContactSenderAPITask(SENDER_DATA_FETCH);
        mUrlsTask.execute(String.format(PATH_FILES, mSenderIp, mPort));
    }

    private void checkSenderAPIAvailablity() {
        if (null != mStatusCheckTask)
            mStatusCheckTask.cancel(true);
        mStatusCheckTask = new ContactSenderAPITask(CHECK_SENDER_STATUS);
        mStatusCheckTask.execute(String.format(PATH_STATUS, mSenderIp, mPort));
    }

    @Override
    public void onPause() {
        super.onPause();
        if (null != mUrlsTask)
            mUrlsTask.cancel(true);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if (null != uiUpdateHandler)
            uiUpdateHandler.removeCallbacksAndMessages(null);
        if (null != mStatusCheckTask)
            mStatusCheckTask.cancel(true);
    }

    public String getSenderSSID() {
        return mSenderSSID;
    }

    public String getSenderIp() {
        return mSenderIp;
    }

    private void loadListing(String contentAsString) {
        Type collectionType = new TypeToken<List<String>>() {
        }.getType();
        ArrayList<String> files = new Gson().fromJson(contentAsString, collectionType);
        progressBar.setVisibility(View.GONE);
        if (null == files || files.size() == 0) {
            mTextView.setText("No Downloads found.\n Tap to Retry");
            mTextView.setVisibility(View.VISIBLE);
        } else {
            mTextView.setVisibility(View.GONE);
            mFilesAdapter.updateData(files);
        }
    }

    private void onDataFetchError() {
        progressBar.setVisibility(View.GONE);
        mTextView.setVisibility(View.VISIBLE);
        mTextView.setText("Error occurred while fetching data.\n Tap to Retry");
    }

    private long postDownloadRequestToDM(Uri uri, String fileName) {

        // Create request for android download manager
        DownloadManager downloadManager = (DownloadManager) getActivity().getSystemService(DOWNLOAD_SERVICE);
        DownloadManager.Request request = new DownloadManager.Request(uri);


        request.setTitle(fileName);

        request.setDescription("ShareThem");
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);


        request.setDestinationInExternalFilesDir(getActivity(),
                Environment.DIRECTORY_DOWNLOADS, fileName);

        return downloadManager.enqueue(request);
    }

    private class SenderFilesListingAdapter extends RecyclerViewArrayAdapter<String, SenderFilesListItemHolder> {
        SenderFilesListingAdapter(List<String> objects) {
            super(objects);
        }

        void updateData(List<String> objects) {
            clear();

            mObjects = objects;
            notifyDataSetChanged();
        }

        @Override
        public SenderFilesListItemHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View itemView = LayoutInflater.from(parent.getContext()).


                    inflate(R.layout.listitem_file, parent, false);
            return new SenderFilesListItemHolder(itemView);
        }


        @Override
        public void onBindViewHolder(SenderFilesListItemHolder holder, int position) {
            final String senderFile = mObjects.get(position);
            holder.itemView.setTag(senderFile);
            final String fileName = senderFile.substring(senderFile.lastIndexOf('/') + 1, senderFile.length());
            holder.title.setText(fileName);
            holder.download.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    postDownloadRequestToDM(Uri.parse(String.format(PATH_FILE_DOWNLOAD, mSenderIp, mPort, mObjects.indexOf(senderFile))), fileName);
                    Toast.makeText(getActivity(), "Downloading " + fileName + "...", Toast.LENGTH_SHORT).show();
                }
            });
        }
    }

    static class SenderFilesListItemHolder extends RecyclerView.ViewHolder {
        TextView title;
        ImageButton download;

        SenderFilesListItemHolder(View itemView) {
            super(itemView);
            title = (TextView) itemView.findViewById(R.id.sender_list_item_name);
            download = (ImageButton) itemView.findViewById(R.id.sender_list_start_download);
        }
    }


    /**
     * Performs network calls to fetch data/status from Sender.
     * Retries on error for times bases on values of {@link FilesListingFragment#senderDownloadsFetchRetry}
     */
    private class ContactSenderAPITask extends AsyncTask<String, Void, String> {

        int mode;
        boolean error;

        ContactSenderAPITask(int mode) {
            this.mode = mode;
        }

        @Override
        protected String doInBackground(String... urls) {
            error = false;
            try {
                return downloadDataFromSender(urls[0]);
            } catch (IOException e) {
                e.printStackTrace();
                error = true;
                Log.e(TAG, "Exception: " + e.getMessage());
                return null;
            }
        }

        // onPostExecute displays the results of the AsyncTask.
        @Override
        protected void onPostExecute(String result) {
            switch (mode) {
                case SENDER_DATA_FETCH:
                    if (error) {
                        if (senderDownloadsFetchRetry >= 0) {
                            --senderDownloadsFetchRetry;
                            if (getView() == null || getActivity() == null || null == uiUpdateHandler)
                                return;
                            uiUpdateHandler.removeMessages(SENDER_DATA_FETCH);
                            uiUpdateHandler.sendMessageDelayed(uiUpdateHandler.obtainMessage(mode), 800);
                            return;
                        } else senderDownloadsFetchRetry = SENDER_DATA_FETCH_RETRY_LIMIT;
                        if (null != getView())
                            onDataFetchError();
                    } else if (null != getView())
                        loadListing(result);
                    else Log.e(TAG, "fragment may have been removed, File fetch");
                    break;
                case CHECK_SENDER_STATUS:
                    if (error) {
                        if (senderStatusCheckRetryLimit > 1) {
                            --senderStatusCheckRetryLimit;
                            uiUpdateHandler.removeMessages(CHECK_SENDER_STATUS);
                            uiUpdateHandler.sendMessageDelayed(uiUpdateHandler.obtainMessage(CHECK_SENDER_STATUS), 800);
                        } else if (getActivity() instanceof ReceiverActivity) {
                            senderStatusCheckRetryLimit = SENDER_DATA_FETCH_RETRY_LIMIT;
                            ((ReceiverActivity) getActivity()).resetSenderSearch();
                            Toast.makeText(getActivity(), getString(R.string.p2p_receiver_error_sender_disconnected), Toast.LENGTH_SHORT).show();
                        } else
                            Log.e(TAG, "Activity is not instance of ReceiverActivity");
                    } else if (null != getView()) {
                        senderStatusCheckRetryLimit = SENDER_DATA_FETCH_RETRY_LIMIT;
                        uiUpdateHandler.removeMessages(CHECK_SENDER_STATUS);
                        uiUpdateHandler.sendMessageDelayed(uiUpdateHandler.obtainMessage(CHECK_SENDER_STATUS), 1000);
                    } else
                        Log.e(TAG, "fragment may have been removed: Sender api check");
                    break;
            }

        }

        private String downloadDataFromSender(String apiUrl) throws IOException {
            InputStream is = null;
            try {
                URL url = new URL(apiUrl);
                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                conn.setReadTimeout(10000 /* milliseconds */);
                conn.setConnectTimeout(15000 /* milliseconds */);
                conn.setRequestMethod("GET");
                conn.setDoInput(true);
                // Starts the query
                conn.connect();
               int response =
                conn.getResponseCode();
               Log.d(TAG, "The response is: " + response);
                is = conn.getInputStream();
                // Convert the InputStream into a string
                return readIt(is);
            } finally {
                if (is != null) {
                    is.close();
                }
            }
        }

        private String readIt(InputStream stream) throws IOException {
            Writer writer = new StringWriter();

            char[] buffer = new char[1024];
            try {
                Reader reader = new BufferedReader(
                        new InputStreamReader(stream, "UTF-8"));
                int n;
                while ((n = reader.read(buffer)) != -1) {
                    writer.write(buffer, 0, n);
                }
            } finally {
                stream.close();
            }
            return writer.toString();
        }
    }
    private static class UiUpdateHandler extends Handler {
        WeakReference<FilesListingFragment> mFragment;

        UiUpdateHandler(FilesListingFragment fragment) {
            mFragment = new WeakReference<>(fragment);
        }

        @Override
        public void handleMessage(Message msg) {
            FilesListingFragment fragment = mFragment.get();
            if (null == mFragment)
                return;
            switch (msg.what) {
                case CHECK_SENDER_STATUS:
                    fragment.checkSenderAPIAvailablity();
                    break;
                case SENDER_DATA_FETCH:
                    fragment.fetchSenderFiles();
                    break;
            }
        }
    }

fragment 文件列表

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    tools:context=".receiver.FilesListingFragment"

    >

    <android.support.v7.widget.RecyclerView
        android:id="@+id/files_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical" />

    <ProgressBar xmlns:android="http://schemas.android.com/apk/res/android"
        style="@android:style/Widget.Holo.ProgressBar"
        android:layout_width="wrap_content"
        android:id="@+id/loading"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:layout_gravity="center" />

    <TextView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/empty_listing_text"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_centerInParent="true"
        android:clickable="true"
        android:gravity="center"
        android:text="No Downloads found.\n Tap to Retry"
        android:visibility="gone" />

</RelativeLayout>

Answer 1

Not annotated parameter overrides @NonNull parameter

这只是一个警告。你有

@Override
public View onCreateView(LayoutInflater inflater...

虽然您要扩展的基类在 inflater 参数上有 nullity 注释。

public View onCreateView(@NonNull LayoutInflater inflater...

您只需在 Android Studio 中按住 alt-enter 即可获得快速修复菜单，其中可以选择在此处添加缺少的注释。

due to this error my code is not working.

缺少这样的注释只会导致警告。 “不工作”的原因是另外一回事。请首先更新您的问题并在此处指定“不工作”对您意味着什么。