如果未连接,如何检查Internet连接并生成对话框

Question

如果未连接,如何检查Internet连接并生成对话框

我的应用程序主要是基于互联网的,当设备没有上网时,它只是崩溃,因为它试图下载文件,但没有成功.我也刚刚在输入时意识到如果它需要的数据离线它也会崩溃.我已经尝试阅读文档并尝试将其添加到我的应用程序,但似乎我需要的东西与我一直在阅读的东西不同.

最好在活动上添加"无互联网连接"对话框,而不是通过吐司.
将"数据不可用"对话框添加到可能在吐司中的片段

我使用我的MainActivity来加载片段,所以我怀疑我可以在其中放置某种代码来显示片段使用区域的对话框.无论哪种方式,我将添加我的MainActivity和我的互联网加载片段.

MainActivity.class:

public class MainActivity extends SherlockFragmentActivity {

    private ViewPager mViewPager;
    private TabSwipe mTabSwipe;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        new FirstLaunchEULA(this).show();



        mViewPager = new ViewPager(this);
        mViewPager.setId(R.id.pager);
        mViewPager.setOffscreenPageLimit(2);
        setContentView(mViewPager);

        final ActionBar bar = getSupportActionBar();
        bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        mTabSwipe = new TabSwipe(this, mViewPager);
        mTabSwipe.addTab(bar.newTab().setText("Games"), A_Internet_Service.class, null);
        mTabSwipe.addTab(bar.newTab().setText("Movies"), Test_Fragment.class, null);
        mTabSwipe.addTab(bar.newTab().setText("Tech"), Purchase_Fragment.class, null);


    }

}

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A_Internet_Service.class:

public class A_Fragment_Service extends Fragment {

    // All static variables
    static final String URL = "this.is.a.url";
    // XML node keys
    static final String KEY_DATA = "data"; // parent node
    static final String KEY_ID = "id";
    static final String KEY_TITLE = "title";
    static final String KEY_DATE1 = "date1";
    static final String KEY_DATE2 = "date2";
    static final String KEY_DATE3 = "date3";
    static final String KEY_DATE2VIS = "date2vis";
    static final String KEY_DATE3VIS = "date3vis";
    static final String KEY_PLATFORMS = "platforms";
    static final String KEY_THUMB_URL = "thumb_url";


    ArrayList<HashMap<String, String>> songsList;
    View view;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        new TheTask().execute();




    /*
    // Click event for single list row
    list.setOnItemClickListener(new OnItemClickListener() {


        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            // TODO Auto-generated method stub

        }
    }); */
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
        view = inflater.inflate(R.layout.main, container, false);
        //list = (ListView) view.findViewById(R.id.data_list);
        return view;

    }

    @Override
    public void onActivityCreated (Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
    }

    class TheTask extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            // TODO Auto-generated method stub
            super.onPreExecute();

        }

        @Override
        protected Void doInBackground(Void... params) {
            XMLParser parser = new XMLParser();
            String xml = parser.getXmlFromUrl(URL); // getting XML from URL
            songsList = new ArrayList<HashMap<String, String>>();
            Document doc = parser.getDomElement(xml); // getting DOM element
            NodeList nl = doc.getElementsByTagName(KEY_DATA);
            for (int i = 0; i < nl.getLength(); i++) {
                // creating new HashMap
                HashMap<String, String> map = new HashMap<String, String>();
                Element e = (Element) nl.item(i);
                // adding each child node to HashMap key => value
                map.put(KEY_ID, parser.getValue(e, KEY_ID));
                map.put(KEY_TITLE, parser.getValue(e, KEY_TITLE));
                map.put(KEY_DATE1, parser.getValue(e, KEY_DATE1));
                map.put(KEY_DATE2, parser.getValue(e, KEY_DATE2));
                map.put(KEY_DATE3, parser.getValue(e, KEY_DATE3));
                map.put(KEY_DATE2VIS, parser.getValue(e, KEY_DATE2VIS));
                map.put(KEY_DATE3VIS, parser.getValue(e, KEY_DATE3VIS));
                map.put(KEY_PLATFORMS, parser.getValue(e, KEY_PLATFORMS));
                map.put(KEY_THUMB_URL, parser.getValue(e, KEY_THUMB_URL));

                // adding HashList to ArrayList
                songsList.add(map);
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            // Getting adapter by passing xml data ArrayList
            LazyAdapter adapter = new LazyAdapter(getActivity(), dataList);
            view = getView();
            ListView mlist = (ListView) view.findViewById(R.id.data_list);
            mlist.setAdapter(adapter);
            super.onPostExecute(result);
        }
    }

}

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编辑片段部分:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
    view = inflater.inflate(R.layout.main, container, false);

    return view;
    if(!isConnected(getActivity())) buildDialog(getActivity()).show();
    else {
        new TheTask().execute();


    }

}

public boolean isConnected(Context context) {

    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netinfo = cm.getActiveNetworkInfo();

    if (netinfo != null && netinfo.isConnectedOrConnecting()) {
        android.net.NetworkInfo wifi = cm.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
        android.net.NetworkInfo mobile = cm.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);

        if((mobile != null && mobile.isConnectedOrConnecting()) || (wifi != null && wifi.isConnectedOrConnecting())) return true;
        else return false;
    } else
        return false;
}

public AlertDialog.Builder buildDialog(Context c) {

    AlertDialog.Builder builder = new AlertDialog.Builder(c);
    builder.setTitle("No Internet connection.");
    builder.setMessage("You have no internet connection");

    builder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which) {

            dialog.dismiss();
        }
    });

    return builder;
}
//All the other code

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Answer 1

Phi*_*oda 11

例如,您可以检查您的Internet连接,如下所示:

如果设备具有Internet连接或即将具有Internet连接,它将返回true.

public boolean isConnected(Context context) {

        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo netinfo = cm.getActiveNetworkInfo();

        if (netinfo != null && netinfo.isConnectedOrConnecting()) {
            android.net.NetworkInfo wifi = cm.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
            android.net.NetworkInfo mobile = cm.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);

            if((mobile != null && mobile.isConnectedOrConnecting()) || (wifi != null && wifi.isConnectedOrConnecting())) return true;
            else return false;
        } else
            return false;
    }

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这就是你在应用程序中使用它的方法:( 例如,在片段onCreateView中,如果设备未连接,则显示对话框,请参阅下面的代码,了解如何生成一个简单的对话框)

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
    view = inflater.inflate(R.layout.yourlayout, container, false);

    // getActivity() will hand over the context to the method
    // if you call this inside an activity, simply replace getActivity() by "this"
    if(!isConnected(getActivity())) buildDialog(getActivity()).show();
    else {
        // we have internet connection, so it is save to connect to the internet here
        new TheTask().execute();
    }

    // do other stuff
    return view;
}

public boolean isConnected(Context context) {

    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netinfo = cm.getActiveNetworkInfo();

    if (netinfo != null && netinfo.isConnectedOrConnecting()) {
        android.net.NetworkInfo wifi = cm.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
        android.net.NetworkInfo mobile = cm.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);

        if((mobile != null && mobile.isConnectedOrConnecting()) || (wifi != null && wifi.isConnectedOrConnecting())) return true;
        else return false;
    } else return false;
}

public AlertDialog.Builder buildDialog(Context c) {

    AlertDialog.Builder builder = new AlertDialog.Builder(c);
    builder.setTitle("No Internet connection.");
    builder.setMessage("You have no internet connection");

    builder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which) {

            dialog.dismiss();
        }
    });

    return builder;
}

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这可以在您的代码中的任何位置完成,例如在Activity的onCreate()方法中,或在Fragment的onCreateView()方法中 - 无论您希望连接到互联网,先检查 - 然后再执行Internet操作.

不要忘记权限:

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

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我希望这有帮助 ;)

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