android - 检查是否有互联网连接

Question

我想问一些我在我的应用程序中不理解的东西。我从我的服务器获取一些数据并使用 google 的 Volley 库将它们显示在 recyclerview 中。到目前为止一切顺利:)。

接下来我从列表中获取这些数据并通过内容提供程序将它们添加到 SQLite。最后，如果没有互联网连接，我应该从手机的存储库中读取它们(现在我应该收到一条 Toast 消息，说明没有互联网连接)。事情是这样的。当我关闭 wifi 时，NoInternet Activity 不会启动。但是，当我将手机置于飞行模式时，NoInternet Activity 会启动。这是我的代码。

public class AnnouncementsFragment extends Fragment {
public String titleForContentProvider;
public String imageForContentProvider;
public String articleForContentProvider;
public static final String TAG = "AelApp";
private ArrayList<MyModel> listItemsList;
private static final String IMAGE_URL = "http://www.theo-android.co.uk/ael/cms/announcement_images/";
RecyclerView myList;
private AnnouncementsAdapter adapter;

public AnnouncementsFragment() {
    // Required empty public constructor
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    getActivity().setTitle("Ανακοινώσεις");

    View rootView = inflater.inflate(R.layout.fragment_announcements, container, false);
    listItemsList = new ArrayList<>();

    myList = (RecyclerView) rootView.findViewById(R.id.listview_announcements);
    final LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
    myList.setHasFixedSize(true);
    myList.setLayoutManager(linearLayoutManager);
    adapter = new AnnouncementsAdapter(getActivity(), listItemsList);
    myList.setAdapter(adapter);

    if (isOnline()) {
        updateAnnouncementsList();
    }else{
        Intent i = new Intent(getActivity(), NoInternet.class);
        startActivity(i);
    }

    return rootView;
}
public void updateAnnouncementsList() {
    listItemsList.clear();


    // Instantiate the RequestQueue.
    RequestQueue queue = Volley.newRequestQueue(getActivity());

    // Request a string response from the provided URL.
    JsonArrayRequest jsObjRequest = new JsonArrayRequest(Request.Method.GET, URL.GET_ANNOUNCEMENTS, new Response.Listener<JSONArray>() {

        @Override
        public void onResponse(JSONArray response) {

            Log.d(TAG, response.toString());
            //hidePD();

            // Parse json data.
            // Declare the json objects that we need and then for loop through the children array.
            // Do the json parse in a try catch block to catch the exceptions
            try {

                for (int i = 0; i < response.length(); i++) {

                    JSONObject post = response.getJSONObject(i);

                    MyModel item = new MyModel();
                    item.setTitle(post.getString("title"));
                    item.setImage(IMAGE_URL + post.getString("announcement_image"));
                    item.setArticle(post.getString("article"));

                    listItemsList.add(item);
                    //Getting the string values out of the JSON response.
                    titleForContentProvider = post.getString("title");
                    imageForContentProvider = post.getString("announcement_image");
                    articleForContentProvider = post.getString("article");
                    //I added them as a key value pair.
                    ContentValues values = new ContentValues();
                    values.put(AELProvider.title,titleForContentProvider);
                    values.put(AELProvider.image,imageForContentProvider);
                    values.put(AELProvider.article,articleForContentProvider);
                    //A Content Resolver that allows the app to
                    //to insert data to the database after
                    //using the Uri defined in the Content Provider
                    Uri uri = getActivity().getContentResolver().insert(AELProvider.CONTENT_URL, values);
                    Log.d("Announcements",uri.toString());
                    Toast.makeText(getContext(), "Announcement added", Toast.LENGTH_LONG)
                            .show();

                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

            // Update list by notifying the adapter of changes
            adapter.notifyDataSetChanged();
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            VolleyLog.d(TAG, "Error: " + error.getMessage());
            //hidePD();
        }
    });
    queue.add(jsObjRequest);

}

protected boolean isOnline() {
    ConnectivityManager cm = (ConnectivityManager)getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netInfo = cm.getActiveNetworkInfo();
    if (netInfo != null && netInfo.isConnectedOrConnecting()) {
        return true;
    } else {
        return false;
    }
}
}

有什么想法吗？

谢谢，

西奥。

Answer 1

你可以试试这个:

public class Common extends BroadcastReceiver
{
    public static boolean internet_status = false;
    public static void checkInternetConenction(Context context) {
        internet_status = false;
        ConnectivityManager check = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        if (check != null) {
            NetworkInfo[] info = check.getAllNetworkInfo();
            if (info != null)
                for (int i = 0; i < info.length; i++) {
                    if (info[i].getState() == NetworkInfo.State.CONNECTED) {
                        internet_status = true;
                    }
                }
        }
    }

    @Override
    public void onReceive(Context context, Intent intent)
    {
        checkInternetConenction(context);
    }
}

并在 Android Menifest 文件中添加接收者:

<receiver android:name=".Common" >
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" >
                </action>
            </intent-filter>
        </receiver>

在您的 Activity 中将 bool 值设置为 false:

static boolean internet_status = false;

& 检查连接使用:

if(Common.internet_status)
                    {
                        //Do your stuff here
                    }
                    else
                    {
                        Toast.makeText(YourActivity.this, "Internet connection is not available", Toast.LENGTH_LONG).show();
                    }