Message while waiting to fetch data

[mobilesenegal]

Hi

My app is accessing the web to populate a list and while I wait I have the message "Empty" appearing for the list on the phone. Once the data is fetched I have the list of items of the list.

How do I do to have / add a message saying "Please wait..." or "Working..." instead of having "Empty" displayed or something showing the progress.

This happens on the phone but not on the emulator.

Thanks

Chris

[grahamhughes]

Hi Chris!!

Easiest option is to shove an Alert on the screen...

private Display display;    // = Display.getDisplay(myMidlet);
private Displayable currentScreen;

// remember this, because we need to put it back later
currentScreen = display.getCurrent();
// create an alert
Alert alert = new Alert(null, "Working...", null, null);
alert.setTimeout(Alert.FOREVER);
// this will add some kind of "busy" animation to the alert
alert.setIndicator(new Gauge(null, false, Gauge.INDEFINITE, Gauge.CONTINUOUS_RUNNING));
// alerts automatically have a "dismiss" command, unless we add one... so add blank one to make it disappear
// (unless you have a genuine "dismiss"/"cancel" command to add)
alert.addCommand(new Command("\u00a0", Command.ITEM, 0));
// make sure there is no command action (unless you want to add one)
alert.setCommandListener(new CommandListener() {
    public void commandAction(Command c, Displayable d) {
        // empty
    }
});
display.setCurrent(alert, currentScreen);

When the download finishes, just set the previous screen back to current.

display.setCurrent(currentScreen);

Graham.

[mobilesenegal]

Hi Graham

Thanks for the answer!

Assume that I am in a screen A and I want to go to a screen B. Screen B will be the screen that fetches data.

Where do I put the different pieces of code you wrote?

I was thinking that I put the code1 and code2 in A. But then currentScreen does not seem to work.

I added a listener and resource manager to check that the download finishes. But the app stays on the alert.

Chris

[grahamhughes]

OK, if you're doing this on a screen transition, you don't want to return back to the same screen.

Forget the references to "currentScreen" in the code I gave above, since you don't want the current screen anyway. Just put the alert on the screen with:

display.setCurrent(alert);

And, in your listener:

display.setCurrent(theNextScreen);

The alert won't disappear until you call setCurrent() to replace it.

[mobilesenegal]

Ok. Thanks.

Could you explain how to use a listener to make a screen visible when the http request has been completed? (the data of the http request are used in the screen).

package view;
public interface LoadListener {
public void loadComplete(Object msg);
}

public class ResourceManager implements Runnable {
private LoadListener listener;
private Object message;

public void load(LoadListener l, Object o) {
listener = l;
message = o;
new Thread(this).start();
}

public void run() {
// http call
// url = "http://...";
//hc = (HttpConnection) Connector.open(url);
// treatement
if (listener != null) {
listener.loadComplete(message);
listener = null;
message = null;
}
}
}

Where to put the display.setCurrent(theNextScreen)?

I call
ResourceManager rm = new ResourceManager();
rm.load(this, "test");
in the currentScreen just after displaying the alert.

It does not seem ok. I do not see how the "wait" is done.

[grahamhughes]

Put the setCurrent() call in the loadComplete() method.