CODEWITHSUNDEEP
java-memidplcdui
Skeng
Skeng

Reputation: 147

Confused with command listeners and new forms J2ME

EDIT: I believe I need help getting the selected element in the list I just managed
for it to display a new form but I'm having a lot of trouble finding code that works
with source 3.0.


I've been trying to make a application that allows a user to select a date then add
and remove events based on the selected date. So far I have created the first screen
which is a list of option for the user to choose from.
These options are:

The issues I'm having is I can't get my head around how to display new forms based on
the selected Item in the list. I found a small tutorial that allowed me to add a command
listener which shows the selected item but I'm having trouble figuring out how it gets the
item selected in the list and how I could create a new form based on the item selected?

Here's my code so far.

    import javax.microedition.lcdui.Alert;
    import javax.microedition.lcdui.AlertType;
    import javax.microedition.lcdui.Command;
    import javax.microedition.lcdui.CommandListener;
    import javax.microedition.lcdui.Display;
    import javax.microedition.lcdui.Displayable;
    import javax.microedition.lcdui.List;
    import javax.microedition.lcdui.Form;
    import javax.microedition.midlet.MIDlet;

    public class mainMidlet extends MIDlet implements CommandListener {

      private Display display;
      private List list = new List("Please Select a Option", List.IMPLICIT);
      private Command select = new Command("Select", Command.SCREEN, 1);
      private Form form;
      Alert alert;

      public mainMidlet() {
        display = Display.getDisplay(this);   

        list.append("Select Date", null);
        list.append("Add Events", null);
        list.append("Remove Events", null);
        list.append("Browse Events", null);
        list.addCommand(select);
        list.setCommandListener(this);

      }

      public void startApp() {
        display.setCurrent(list);
      }

      public void pauseApp() {
      }

      public void destroyApp(boolean unconditional) {
      }

      public void commandAction(Command command, Displayable displayable) {
        if (command == List.SELECT_COMMAND) {
          String selection = list.getString(list.getSelectedIndex());
          alert = new Alert("Option Selected", selection, null, null);
          alert.setTimeout(Alert.FOREVER);
          alert.setType(AlertType.INFO);
          display.setCurrent(alert);
        } else if (command == select) {
          destroyApp(false);
          notifyDestroyed();
        }
      }
    }

Upvotes: 3

Views: 1159

Answers (1)

Yaroslav Mytkalyk
Yaroslav Mytkalyk

Reputation: 17105

You can add several forms and switch between them

  public void commandAction(Command command, Displayable displayable) {
      if (displayable == list) {
          if (command == List.SELECT_COMMAND) {
              switch (list.getSelectedIndex()) {
                  case 0: // select date
                      display.setCurrent(someForm);
                      break;
                  case 1: //add events
                      display.setCurrent(someOtherForm);
                      break;
              }
          } else if (command == select) {
             destroyApp(false);
             notifyDestroyed();
          }
      }
      if (displayable == someForm) {
          //but it's better practice to make each form a different class implementing CommandListener and it's own commandAction. And leave the display public static in MIDlet class
          //...
      }
  }

Upvotes: 4

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