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Button enable signal does not work.

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  • K Offline
    K Offline
    Kycho
    wrote on last edited by Kycho
    #1

    Hi, I don't know what went wrong.

    1. I set the default of the button to false.
    findButton->setEnabled(false);
    
    1. I connected as below.
    connect(lineEdit, SIGNAL(textChanged(const QString &)),
    this, SLOT(enableFindButton(const Qstring &)));
    

    3.I defined enableFindButton like this.

    void FindDialog::enableFindButton(const QString &text){
        findButton->setEnabled(!text.isEmpty());
    }
    

    But, It is not work.

    What did I do wrong?

    Thanks.

    1 Reply Last reply
    0
    • Christian EhrlicherC Offline
      Christian EhrlicherC Offline
      Christian Ehrlicher
      Lifetime Qt Champion
      wrote on last edited by
      #2

      @Kycho said in Button enable signal does not work.:

      connect(lineEdit, SIGNAL(textChanged(const QString &)),
      this, SLOT(enableFindButton(const Qstring &)));

      There is a typo (Qstring). You will also get a warning at runtime about this error.
      To avoid this completely I suggest to use the new signal/slot syntax:

      connect(lineEdit, &QLineEdit::textChanged, this, &FindDialog::enableFindButton);

      Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
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      K 1 Reply Last reply
      6
      • Christian EhrlicherC Christian Ehrlicher

        @Kycho said in Button enable signal does not work.:

        connect(lineEdit, SIGNAL(textChanged(const QString &)),
        this, SLOT(enableFindButton(const Qstring &)));

        There is a typo (Qstring). You will also get a warning at runtime about this error.
        To avoid this completely I suggest to use the new signal/slot syntax:

        connect(lineEdit, &QLineEdit::textChanged, this, &FindDialog::enableFindButton);

        K Offline
        K Offline
        Kycho
        wrote on last edited by
        #3

        @Christian-Ehrlicher Thank you.
        I've fixed the issue.

        1 Reply Last reply
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