3
votes

I made an app that contains a webview, that checks connection when webview starts to load a url. Works well on the AVD but when I tested it on an actual device, a big bug happens. I assume that webview didn't load because all it displays is black. No matter what I do, all black.. 3 days before I kinda figured out how to make it work, it first needs to see the target url in a browser app before it opens the target url on my app. Bottom line, the webview doesn't show the target url unless you first open it in a browser. I did research on this but all i can find are answers on how to open a link in the webview that won't open a browser.

Here are the codes on my main activity:

public class MainActivity extends Activity
{

private WebView wv;
private ProgressBar progress;
private static String mycaturl=" *target url* ";

@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);     
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
    StrictMode.setThreadPolicy(policy);
    if (reachable(this))
    {
        Toast.makeText(this, "Reachable", Toast.LENGTH_SHORT).show();
        buildwv( savedInstanceState, WebSettings.LOAD_DEFAULT );
    }
    else if (!reachable(this))
    {
        Toast.makeText(this, "Unreachable", Toast.LENGTH_SHORT).show();
        eolc( savedInstanceState );
    }
    else
    {
        Toast.makeText(this, "onCreate error.", Toast.LENGTH_SHORT).show();
        finish();
    }
}


@SuppressLint({ "SetJavaScriptEnabled" })
public void buildwv(Bundle sis, int load)
{
    setContentView(R.layout.activity_main);

    //assigning objects to variables
    wv=(WebView) findViewById(R.id.wv);
    wv.setWebViewClient( new wvc() );
    progress=(ProgressBar) findViewById(R.id.progress);

    //websettings
    WebSettings ws = wv.getSettings();
    ws.setAppCacheMaxSize( 100 * 1024 * 1024 ); // 100MB
    ws.setAppCachePath( this.getCacheDir().getAbsolutePath() );
    ws.setAllowFileAccess( true );
    ws.setAppCacheEnabled( true );
    ws.setJavaScriptEnabled( true );
    ws.setCacheMode(load);

    //if instance is saved, to catch orientation change
    if(sis==null)
    {   wv.loadUrl(mycaturl);   }
}


public void eolc(final Bundle sis)
{
    AlertDialog.Builder alertDialog = new AlertDialog.Builder( MainActivity.this );

    alertDialog.setTitle("ERROR 1");
    alertDialog.setMessage("Host is unreachable. Load from cache or exit.");
    alertDialog.setIcon(R.drawable.tick);

    alertDialog.setPositiveButton( "Load from Cache", new DialogInterface.OnClickListener()
    {
        public void onClick(DialogInterface dialog,int which)
        {
            // Write your code here to execute after dialog
            Toast.makeText(getApplicationContext(), "You chose to load cache.", Toast.LENGTH_SHORT).show();
            buildwv( sis, WebSettings.LOAD_CACHE_ELSE_NETWORK );
        }
    });

    alertDialog.setNeutralButton( "Help", new DialogInterface.OnClickListener()
    {
        public void onClick(DialogInterface dialog, int which)
        {
            Toast.makeText(getApplicationContext(), "You chose Help. EOLC", Toast.LENGTH_SHORT).show();
            wv.loadUrl("file:///android_asset/otherpages/errorpage.htm");
        }
    });

    alertDialog.setNegativeButton( "Exit", new DialogInterface.OnClickListener()
    {
        public void onClick(DialogInterface dialog, int which)
        {
            // Write your code here to execute after dialog
            Toast.makeText(getApplicationContext(), "You chose to exit.", Toast.LENGTH_SHORT).show();
            finish();
            }
    });

    alertDialog.create();
    alertDialog.show();
}


public void roe()
{
    AlertDialog.Builder alertDialog = new AlertDialog.Builder( MainActivity.this );

    alertDialog.setTitle("ERROR 2");
    alertDialog.setMessage("Host is unreachable. Restart to load cache or exit.");
    alertDialog.setIcon(R.drawable.tick);
    alertDialog.setPositiveButton( "Restart", new DialogInterface.OnClickListener()
    {
        public void onClick(DialogInterface dialog,int which)
        {
            Toast.makeText(getApplicationContext(), "You chose to restart and load cache.", Toast.LENGTH_SHORT).show();
            Intent i = getBaseContext().getPackageManager()
                     .getLaunchIntentForPackage( getBaseContext().getPackageName() );
            i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK );
            startActivity(i);
        }
    });
    alertDialog.setNeutralButton( "Help", new DialogInterface.OnClickListener()
    {
        public void onClick(DialogInterface dialog, int which)
        {
            Toast.makeText(getApplicationContext(), "You chose Help. ROE", Toast.LENGTH_SHORT).show();
            wv.stopLoading();
            wv.loadUrl("file:///android_asset/otherpages/errorpage.htm");
        }
    });
    alertDialog.setNegativeButton( "Exit", new DialogInterface.OnClickListener()
    {
        public void onClick(DialogInterface dialog, int which)
        {
            Toast.makeText(getApplicationContext(), "You chose to exit.", Toast.LENGTH_SHORT).show();
            finish();
        }
    });
    alertDialog.create();
    alertDialog.show();
}


private class wvc extends WebViewClient
{

      //when page started loading
      public void onPageStarted(WebView view, String url, Bitmap favicon)
      {
          //circular progress bar open
          progress.setVisibility(View.VISIBLE);

          //if reachable and setting cache on every new page
          //setcache(getApplicationContext());

          WebSettings ws = wv.getSettings();

          if ( !reachable(getApplicationContext()) )
          {
              if ( ws.getCacheMode() == WebSettings.LOAD_DEFAULT )
              {
                  roe();
              }
              else if ( ws.getCacheMode() == WebSettings.LOAD_CACHE_ELSE_NETWORK )
              {
                  Toast.makeText(getApplicationContext(), "loading cache coz not reachable", Toast.LENGTH_SHORT).show();
              }

          }
      }


      //when page finished
      @Override
      public void onPageFinished(WebView view, String url) 
      {
          super.onPageFinished(view, mycaturl);
          Toast.makeText(getApplicationContext(), "PAGE DONE LOADING!!", Toast.LENGTH_SHORT).show();

          //circular progress bar close
          progress.setVisibility(View.GONE);
      }


      //when received an error
      @Override
      public void onReceivedError(WebView view, int errorCode, String description, String failingUrl)
      {
          wv.stopLoading();
          //wv.loadUrl("file:///android_asset/otherpages/errorpage.htm");
          WebSettings ws = wv.getSettings();

          if ( ws.getCacheMode() == WebSettings.LOAD_DEFAULT )
          {
              Toast.makeText(getApplicationContext(), "Page unavailable", Toast.LENGTH_SHORT).show();
          }
          else
          {
              Toast.makeText(getApplicationContext(), "Page not cached", Toast.LENGTH_SHORT).show();
          }
          roe();
      }
  }


//checking connectivity by checking if site is reachable
public static boolean reachable(Context context) 
{
    final ConnectivityManager connMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    final NetworkInfo netInfo = connMgr.getActiveNetworkInfo();

    if (netInfo != null && netInfo.isConnected()) 
    {
        try 
        {
            URL url = new URL(mycaturl);
            HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
            urlc.setConnectTimeout(5000); // five seconds timeout in milliseconds
            urlc.connect();
            if (urlc.getResponseCode() == 200) // good response
            {   return true;    } else {    return false;   }
        }
        catch (IOException e)
        {   return false;   }
    }
    else
    {   return false;   }
}


//options menu inflation
@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;
}


//when back button is pressed
public void onBackPressed ()
{
    if (wv.isFocused() && wv.canGoBack())
    {   wv.goBack();    }   else {  finish();   }
}


//when options button is pressed
@Override

public boolean onOptionsItemSelected(MenuItem item)
{
    switch (item.getItemId())
    {
        case R.id.item1:
            wv.loadUrl("file:///android_asset/otherpages/errorpage.htm");
            break;
        case R.id.item2:
            String currurl=wv.getUrl();
            wv.loadUrl(currurl);   
            break;
        case R.id.item3:
            Intent i = getBaseContext().getPackageManager()
             .getLaunchIntentForPackage( getBaseContext().getPackageName() );
            i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(i);
            break;
        case R.id.item4:
            finish();
            break;
        default:
            break;
    }
    return true;
} 


//saving instance state
@Override
protected void onSaveInstanceState(Bundle outState )
{
    super.onSaveInstanceState(outState);
    wv.saveState(outState);
}


//restoring instance state
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState)
{
    super.onSaveInstanceState(savedInstanceState);
    wv.restoreState(savedInstanceState);
}

}

And yes, I've added these too:

<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" /> 
1
yes i think ur device is 4.0.1 version ?Android Killer
What does logcat say when this happens? Are you sure you added the android.permission.INTERNET to your AndroidManifest.xml?Ivan Bartsov
@IvanBartsov as he has mentioned it's working on AVD, so there must be this permission in menifest, isn't it ?Android Killer
@AndroidKiller I tried it on a 2.3.6 and a 4.1.2, the same thing happens.Lendl Leyba
@AndroidKiller yeah, you're probably right. But AVD sometimes acts weird in unexpected ways, never hurts to double-check the obvious stuff.Ivan Bartsov

1 Answers

-1
votes

Ok, here's how to really do this.

1)Never change strict mode. Needing to do this means 99% of the time that you're not writing it the right way. Strict mode is there for a reason- to stop the user from thinking the app is crashed. Actually, disabling it can crash the app if you trip the watchdog timer (which you may be doing).

2)Never write if(x) else if (!x) else. The last else is redundant, and the else if is causing you to do x again, when it almost always is wrong to do so.

3)There's a better way to do the timing thing for the dialog. Write a custom WebViewClient for your WebView, and set it setWebViewClient. Override onPageFinished to set a global flag to know the page loaded. In your onCreate, create the webview, set this client, and set a timer. When the timer goes off, check the flag. If the flag is still false, stop loading the web page and pop up the dialog.

EDIT: additions

4)And I just noticed calling reachable again in onPageStarted? Really calling that way too much.

If you do this:

1)your buildwv function becomes your onCreate function, and add the code in to set the custom client and start the timer

2)Your eolc function becaomes the body of your timer, after a check against the global flag

3)Your roe function should really go away.

4)Your onPageStarted function probably goes away. It doesn't look like its doing anything useful to me that isn't handled by the timer to check if the page is loaded. Keep it around just for the progress bar work.

5)reachable goes away.