CODEWITHSUNDEEP
javacodenameone
C Java
C Java

Reputation: 446

Codename one new gui builder-back command from EVERY form navigation

I am navigating between forms in the NEW GUI builder. The old one had a back button on every form by default.

How do I enable the back button on new gui builder in every form, every time i navigate in a new form? Tried through constants in theme.res. It is still not enabled by default.

Furthermore, is the method "new form1.show" the best way to navigate between forms ? (see code)

Assuming name files:

Main.java, myapplication.java, Form1 ,Form2 ,Form3

Code for navigation, assuming names button1 and Form3:

public void onbutton1ActionEvent(com.codename1.ui.events.ActionEvent ev) {
        new Form3().show();   
    }

Back command from old gui builder, not working here:

 public Form showForm(String resourceName, Command sourceCommand) {
        try {
            Form f = (Form)formNameToClassHashMap.get(resourceName).newInstance();
            Form current = Display.getInstance().getCurrent();
            if(current != null && isBackCommandEnabled() && allowBackTo(resourceName)) {
                f.putClientProperty("previousForm", current);
                setBackCommand(f, new Command(getBackCommandText(current.getTitle())) {
                    public void actionPerformed(ActionEvent evt) {
                          back(null);
                    }
                });
            }
            if(sourceCommand != null && current != null && current.getBackCommand() == sourceCommand) {
                f.showBack();
            } else {
                f.show();
            }
            return f;
        } catch(Exception err) {
            err.printStackTrace();
            throw new RuntimeException("Form not found: " + resourceName);
        }
    }

I've tried:

  form.setBackCommand(cmd);

public Command setBackCommand(String title, ActionListener<ActionEvent> listener)
public void setBackCommand(Command cmd)
public Command setBackCommand(String title, BackCommandPolicy policy, ActionListener<ActionEvent> listener)
public void setBackCommand(Command cmd, BackCommandPolicy policy)
    boolean onBack() {
            return true;
        }

https://www.codenameone.com/blog/toolbar-back-easier-material-icons.html on main.java and myapplication.java did not accept the commands.

Form3.getToolbar().setBackCommand("", e -> Form3.showBack());

althouth is should not work only for form3, but every form.

Did not work either. Putting "back command" on every sidemenu would not be the ideal solution, because we might be navigating to each form from different forms.

EXTRA: Is there a way to enable global toolbar and global commands for all forms, so i do not copy paste the toolbar code for each new form? If not answered here, i might make a new thread.

Thanks.

Upvotes: 4

Views: 222

Answers (1)

Shai Almog
Shai Almog

Reputation: 52770

The old GUI builder handled navigation as it was designed at a time when Nokia was the worlds leader in the mobile phone industry and a 4in device was considered large. Back then we assumed the UI was simpler for each form and the navigation was the hard part.

This changed. But the bigger problem for most developers was the concept of stateless navigation which triggered a lot of issues both in design and functionality.

The new GUI builder doesn't include any navigation code or any global code. Each form stands on its own.

Having said that you can implement your own state machine by just keeping form instances and showing the form you want to navigate to e.g.:

public static class Controller { 
    private static Form1 f1;
    private static Form2 f2;


    public static void showF1() {
         if(f1 == null) f1 = new Form1();
         f1.show();
    }

    // etc...
}

I used static context for simplicity but you can implement your own strategy. Notice that you can also insert global logic here e.g. add the toolbar as a function like:

 private static void initForm(Form f) {
    // add global commands to the toolbar
 }

Alternatively you can derive all the forms from a common base class as the new GUI builder doesn't restrict your inheritance.

Upvotes: 3

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