Question

I have an activitiy with an layout and a ProgressBar:

public class Saldo_Menu extends Activity implements OnClickListener, OnLongClickListener {

static InternetHelper IH;
ProgressBar pleasewait;  



    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        pleasewait=(ProgressBar)findViewById(R.id.pleasewait);

        IH=new InternetHelper(this);

        pleasewait.setVisibility(View.INVISIBLE);
}

I want to activate the progressbar from this helper class InternetHelper, can somebody give me a small example. This gives a nullpointer, since I know I can’t access the UI from there:

 public InternetHelper (Context context) {
        myContext = context;

         }

public void ShowProgressBar(boolean show){
 if (show){pleasewait.setVisibility(View.VISIBLE);}else{pleasewait.setVisibility(View.INVISIBLE);}
}

Answer 1

Save a reference to progress bar in your helper class and then use that to access it.

ProgressBar myBar;

public InternetHelper (Context context, ProgressBar pleasewait) {
        myContext = context;
        myBar = pleasewait;
        }

Then you should be able to use your ShowProgressBar(boolean) function without any problem.