Get TextField->text() from slot Blackberry 10

Question

I'm a complete beginner in Blackberry 10 development. I'm developing an app that should take user input from a text box and search if there is an occurrence of the word in a text file. I'm using the triggered() signal of ActionItem to invoke the search. However, when I try to fetch the user input from within the slot it always returns an empty string ''. What mistake I'm I making.

Thank you in advance.

Here is the code:

main.qml

TextField {
        objectName: "anagram"
        hintText: "Enter anagram to search"
        verticalAlignment: VerticalAlignment.Center
        horizontalAlignment: HorizontalAlignment.Center

        input {
            submitKey: SubmitKey.Done

        }            
}

application.cpp

ActionItem *main = root->findChild<ActionItem*>("search");
bool res1 = QObject::connect(main, SIGNAL(triggered()), this, SLOT(onSearch()));


void ApplicationUI::onSearch()
{
    qDebug() << "slot activated";
    QmlDocument *qml = QmlDocument::create("asset:///main.qml").parent(this);
    AbstractPane *root = qml->createRootObject<AbstractPane>();
    Application::instance()->setScene(root);
    TextField* query = root->findChild<TextField*>("anagram");
    //THE STRING BELOW ALWAYS RETURNS ''
    QString search = query->text();
    ...

Answer 1

Introduction

When the slot onSearch is invoked you are effectively creating an additional UI, unrelated to the one that actually emitted the signal.

Since there's no default setting for the text property of anagram, what you have concluded is correct; it will always yield an empty string since the field will always be freshly created.

---

Solution

You will need to use the root associated with the current UI (that the user has inputted data to), instead of creating a new one.

Assuming that you have declared root as a data-member of ApplicationUI, the below would do what you'd expect (and want).

void ApplicationUI::onSearch()
{
    qDebug() << "slot activated";
    TextField* query = root->findChild<TextField*>("anagram");
    QString search = query->text();
    // ... 
}

---

_{Alternative solution}

You could also access the current loaded scene (the equivalent of root in your snippet) by calling scene() on the pointer-to AbstractPane returned by Application::instance ():

AbstractPane *   current_scene = Application::instance ()->scene ();
QString search = current_scene->findChild<TextField*> ("anagram")->text ();