Question

I have created appliction with webview. if i have do any action and the net is disconnected i want to display one alert. I have tried the following,

added this in oncreate method.

public class AndroidNetTestActivity extends Activity {

    public static WebView webview;
    private Handler mHandler = new Handler();       
    private boolean isConnected = true;
    final String offlineMessageHtml = "Net is disconnected";
    final String timeoutMessageHtml = "Connection timed out";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        webview=(WebView)findViewById(R.id.webview);
        webview.getSettings().setJavaScriptEnabled(true); 
        webview.loadUrl("file:///android_asset/www/index.htm");      
        webview.addJavascriptInterface(new MyJavaScriptInterface(), "Android");
        isConnected=isNetworkAvailable();
        webview.setNetworkAvailable(isConnected);
        webview.setWebViewClient(new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                isConnected=isNetworkAvailable();
                if (isConnected) {
                    // return false to let the WebView handle the URL
                    return false;
                } else {
                    // show the proper "not connected" message
                    view.loadData(offlineMessageHtml, "text/html", "utf-8");
                    // return true if the host application wants to leave the current 
                    // WebView and handle the url itself
                    return true;
                }
            }
            @Override
            public void onReceivedError (WebView view, int errorCode, 
                String description, String failingUrl) {
                if (errorCode == ERROR_TIMEOUT) {
                    view.stopLoading();  // may not be needed
                    view.loadData(timeoutMessageHtml, "text/html", "utf-8");
                }
            }
        });
        webview.setWebChromeClient(new WebChromeClient());        
    }

    final class MyJavaScriptInterface
    {
        public void ProcessJavaScript(final String scriptname, final String args)
            {             
                mHandler.post(new Runnable()
                    {
                        public void run()
                            {
                                //ToDo
                            }
                    });
            }
    }  

    public boolean isNetworkAvailable() {
           Context context = getApplicationContext();
           ConnectivityManager connectivity = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
           if (connectivity == null) {
              //boitealerte(this.getString(R.string.alert),"getSystemService rend null");
           } else {
              NetworkInfo[] info = connectivity.getAllNetworkInfo();
              if (info != null) {
                 for (int i = 0; i < info.length; i++) {
                    if (info[i].getState() == NetworkInfo.State.CONNECTED) {
                       return true;
                    }
                 }
              }
           }
           return false;
        }
}

if i clicking on the log in button, it should show an error message if net is not available.

but it is not working. please check my code and tell me what i did wrong

Answer 1

ok… i updated your code. just have a look

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.Bitmap;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.os.Handler;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;


public class AndroidNetTestActivity extends Activity {

    public static WebView webview;
    private Handler mHandler = new Handler();       
    private boolean isConnected = true;
    final String offlineMessageHtml = "Net is disconnected";
    final String timeoutMessageHtml = "Connection timed out";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.full_screen_image_layout);

        webview=(WebView)findViewById(R.id.webview);
        webview.getSettings().setJavaScriptEnabled(true); 
        webview.loadUrl("http://www.google.com");      
        webview.addJavascriptInterface(new MyJavaScriptInterface(), "Android");
        isConnected=isNetworkAvailable();
        webview.setNetworkAvailable(isConnected);
        webview.setWebViewClient(new WebViewClient() {
            /* (non-Javadoc)
            * @see android.webkit.WebViewClient#onPageStarted(android.webkit.WebView, java.lang.String, android.graphics.Bitmap)
            */
            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon) {
                System.out.println("page loading started");
                // TODO Auto-generated method stub
                if(!isNetworkAvailable2())
                {
                    showInfoMessageDialog("network not available");
                    System.out.println("network not available");
                    return;
                }
                else System.out.println("network available");

                super.onPageStarted(view, url, favicon);

            }

            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                isConnected=isNetworkAvailable2();
                if (isConnected) {
                    // return false to let the WebView handle the URL
                    return false;
                } else {
                    // show the proper "not connected" message
                // view.loadData(offlineMessageHtml, "text/html", "utf-8");
                    // return true if the host application wants to leave the current 
                    // WebView and handle the url itself
                    return true;
                }
            }
            @Override
            public void onReceivedError (WebView view, int errorCode, 
                String description, String failingUrl) {
                if (errorCode == ERROR_TIMEOUT) {
                    view.stopLoading();  // may not be needed
                // view.loadData(timeoutMessageHtml, "text/html", "utf-8");
                }
            }
        });
        //webview.setWebChromeClient(new WebChromeClient());        
    }

    final class MyJavaScriptInterface
    {
        public void ProcessJavaScript(final String scriptname, final String args)
            {             
                mHandler.post(new Runnable()
                    {
                        public void run()
                            {
                                //ToDo
                            }
                    });
            }
    }  

    private void showInfoMessageDialog(String meaasge)
    {
        AlertDialog alertDialog = new AlertDialog.Builder(
                AndroidNetTestActivity.this).create();
        alertDialog.setTitle("Connectivity");
        alertDialog.setMessage(meaasge);
        alertDialog.setButton("OK",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog,
                            int which) {
                        dialog.cancel();
                    }
                });
        //alertDialog.setIcon(R.drawable.error);
        alertDialog.show();
    }

    private boolean isNetworkAvailable2()
    {
        System.out.println("isNetworkAvailable2 called");
        NetworkInfo info = (NetworkInfo) ((ConnectivityManager) getApplicationContext()
                .getSystemService(Context.CONNECTIVITY_SERVICE))
                .getActiveNetworkInfo();

        if (info == null || !info.isAvailable() || !info.isConnected())
            return false;
        else return true;
    }


    public boolean isNetworkAvailable() {
        Context context = getApplicationContext();
        ConnectivityManager connectivity = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        if (connectivity == null) {
            //boitealerte(this.getString(R.string.alert),"getSystemService rend null");
        } else {
            NetworkInfo[] info = connectivity.getAllNetworkInfo();
            if (info != null) {
                for (int i = 0; i < info.length; i++) {
                    if (info[i].getState() == NetworkInfo.State.CONNECTED) {
                    return true;
                    }
                }
            }
        }
        return false;
        }
}