Android unknown error occurred in android when clicking on one of tab Activity
<p>unknown error occurred in android when clicking on one of tab Activity in android although it working fine but message displayed in toast "unknown error occurred"</p>

<p>public class importDiagram extends Activity {</p>

<pre><code>private UserLogIn mUserLogIn = null;

private Button mCategory = null;    
GeneralWebMethod webMethods = null;
private ListView mDiagramList = null;

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater mInflater = getMenuInflater();
    mInflater.inflate(R.menu.import_diagram_menu, menu);
    return true;
}

@Override
public boolean onMenuItemSelected(int featureId, MenuItem item) {

    if(item.getItemId() == R.id.refresh_ID){
        Toast.makeText(importDiagram.this, "Refreshing Diagram List", Toast.LENGTH_LONG).show();

        if(isOnline()){
            progressDialog = ProgressDialog.show(importDiagram.this,"Diagrams"  ,"Diagrams downloading...");
            diagramDisplayThread = new DiagramDisplayThread();
            diagramDisplayThread.execute((Void[])null);
        }else{
            NoInternetAlertBox();
        }
    }
    return true;
}
</code></pre>
