如何使用onpause和onresume创建活动来浏览URL？

Question

Can you please help me on this?

How to create a activity which runs a url at oncreate method if Internet connection is available?

I want to check Internet connection is available or not every 5 seconds, if Internet connection gone it will alert as dilog box only one time.

If Internet connection comes then activty will resume where the session was closed

Here below my code is:

    public class MainActivity extends Activity {

private String URL="http://www.moneycontrol.com/";

private Handler mHandler = new Handler();

private boolean isRunning = true;

private TextView textlabel=null;    

public WebView webview=null;


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

        textlabel=(TextView)findViewById(R.id.textlabel);
        displayData();

    }

    private void Chekstate() {

    new Thread(new Runnable() {
        @Override
        public void run() {
            // TODO Auto-generated method stub
            while (isRunning) {
                try {
                    Thread.sleep(1000);
                    mHandler.post(new Runnable() {

                        @Override
                        public void run() {
                            // TODO Auto-generated method stub
                            // Write your code here to update the UI.
                            displayData();
                        }
                    });
                } catch (Exception e) {
                    // TODO: handle exception
                }
            }
        }
    }).start(); 

    }


    @SuppressWarnings("deprecation")
    private void displayData() {
        ConnectivityManager cn=(ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo nf=cn.getActiveNetworkInfo();
        if(nf != null && nf.isConnected()==true )
        {
           textlabel.setText("Network Available");
           Webview();
        }
        else
        {
           textlabel.setText("Network Not Available");
           final AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
           alertDialog.setTitle("Intenet Connecction");
           alertDialog.setMessage("Internet Connetion is not available now.");
           alertDialog.setButton(" OK ", new OnClickListener() {

            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                alertDialog.dismiss();
            }
        });
           alertDialog.show();
        }       
    } 


      @Override
        protected void onResume() {
            super.onResume();

        }

        @Override
        protected void onPause() {
            super.onPause();

        }

    @SuppressLint("SetJavaScriptEnabled")
    private void Webview() {
        webview= (WebView) findViewById(R.id.webview);
        webview.getSettings().setJavaScriptEnabled(true);
        webview.setWebViewClient(new WebViewClient());
        webview.loadUrl(URL);
        webview.setInitialScale(1);
        webview.getSettings().setBuiltInZoomControls(true);
        webview.getSettings().setUseWideViewPort(true);

    }



    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

Answer 1

to check internet connectivity you can use the following.

Add the following permissions in manifest

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

Use a handler

Handler mHandler = new Handler();
boolean isRunning = true;

Then, use this thread from your onCreate() method :

new Thread(new Runnable() {
        @Override
        public void run() {
            // TODO Auto-generated method stub
            while (isRunning) {
                try {
                    Thread.sleep(5000);
                    mHandler.post(new Runnable() {

                        @Override
                        public void run() {
                            // TODO Auto-generated method stub
                            // Write your code here to update the UI.
                            displayData();
                        }
                    });
                } catch (Exception e) {
                    // TODO: handle exception
                }
            }
        }
    }).start(); 

Then, declare this method which called by your handler at every 5 seconds :

    private void displayData() {
    ConnectivityManager cn=(ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo nf=cn.getActiveNetworkInfo();
    if(nf != null && nf.isConnected()==true )
    {
        Toast.makeText(this, "Network Available", Toast.LENGTH_SHORT).show();
        myTextView.setText("Network Available");
    }
    else
    {
        Toast.makeText(this, "Network Not Available", Toast.LENGTH_SHORT).show();
        myTextView.setText("Network Not Available");
    }       
} 

To stop thread call this :

   isRunning = false;

Alterntively you ca use the below. But it does not check connectivty every 5 seonds

public class CheckNetwork {
private static final String TAG = CheckNetwork.class.getSimpleName();
public static boolean isInternetAvailable(Context context)
{
NetworkInfo info = (NetworkInfo) ((ConnectivityManager)
context.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();

if (info == null)
{
     Log.d(TAG,"no internet connection");
     return false;
}
else
{
    if(info.isConnected())
    {
        Log.d(TAG," internet connection available...");
        return true;
    }
    else
    {
        Log.d(TAG," internet connection");
        return true;
    }
   }
 }
}

In your activity in onCreate()

if(CheckNetwork.isInternetAvailable(MainActivtiy.this))  //if connection available
{

}

http://developer.android.com/training/monitoring-device-state/connectivity-monitoring.html

You can use a BroadCast Reciever. When connectivity is lost the system broadcasts. But i suggest not to use broadcast reciever.