Codenameone:如何防止android硬件后退按钮退出应用？

public class MyApplication {

    public void start() {
        if (Display.getInstance().isInitialized()) {
            // 应用已经启动
            return;
        }
        
        Form mainForm = new Form("Main Form");
        mainForm.setBackCommand(new Command("Back") {
            @Override
            public void actionPerformed(ActionEvent evt) {
                // 处理后退按钮事件
            }
        });
        
        mainForm.show();
    }
    
    public void stop() {
        Display.getInstance().callSerially(() -> {
            Form currentForm = Display.getInstance().getCurrent();
            if (currentForm != null) {
                currentForm.setBackCommandEnabled(false);
            }
        });
    }
}