Question

I am using a popup screen to show the update status of background uploading processes. I want to cancel the uploading in between. I am trying to achieve this either by addin a button to the pop up screen or with the physical backbutton of the device. But it seems that none of the events generated are caught by the app.

Here is how I am creating a popup screen and displaying it t user

    DialogFieldManager manager = new DialogFieldManager();
                        //DialogFieldManager manager = (DialogFieldManager)getDelegate();
                        statusUpdate = new LabelField("Please Wait...");
                        manager.addCustomField(statusUpdate);
                        _gaugeField = new GaugeField("", 0, 100, 0, GaugeField.PERCENT);
                        manager.addCustomField(_gaugeField);
                        cncl_Btn = new ButtonField("Cancel",ButtonField.CONSUME_CLICK | ButtonField.FIELD_HCENTER | ButtonField.NEVER_DIRTY);
                        manager.addCustomField(cncl_Btn);
                        cancelFlag = 0;
                        cncl_Btn.setChangeListener(new FieldChangeListener()
                        {

                            public void fieldChanged(Field field, int context) {
                                //  Auto-generated method stub
                                UiApplication.getUiApplication().invokeLater(new Runnable()
                                {               
                                    public void run()
                                    {
                                        cancelFlag = 1;
                                        //onClose();//as this method exited from application
                                       // close();//this method gave me IllegalStateException
                                    }
                                 });

                            }

                        });

                        //BackUpScreen.this.addMenuItem(_viewItem);
                        popup = new PopupScreen(manager);
UiApplication.getUiApplication().pushScreen(popup);

Soon afther this line I am calling the actual upload process in a thread like this

UiApplication.getUiApplication().invokeLater(new Runnable() { 
                            public void run() {
                                    //.... do other stuff I wanted done...
                                backUpThread = Thread.currentThread();
                                    uploadItems();


                            }
                    });

But if I press the cancel button inside the popup screen its not responding. I checked this by adding a breakpoint inside the fieldchange listener method of button.

How can I do this in blackberry?

Answer 1

The call to invokeLater (int the second bit of code) causes that Runnable to be executed on the event thread. If anything you do on the event thread blocks then the UI will become unresponsive as you describe. Any calls that may block must not be run on the event thread.