How to add style via setStyleSheet() without losing orignal style in Qt?

Question

I Konw I can use setStyleSheet() to set style in Qt.But I encountered a problem,when I used setStyleSheet() twice first styles lost,which a

Answer 1

This is in response to your comment on the accepted answer.

You can prevent overwriting stylesheets properties by setting the constant values to the parent (permitting that the parent's style isn't being changed dynamically as well). Only set the values that you change with C++ to the child item.

parentWidget->setStyleSheet( "QLabel#yourLabel { color:red; }" );
yourLabel->setStyleSheet( "QLabel { border-image:url(...) };" );

This will retain all of the parents properties that have been set on the widget when you change the widget's stylesheet.

Furthermore, this removes the case of a very large string, which is possible in the accepted answer. Frequent changes will inefficiently append the string with previously defined styles that will not be used.

Answer 2

You can set stylesheets without QLabel tag:

setStyleSheet("color:red;");

After setting one stylesheet property, you can add another property like:

setStyleSheet( styleSheet().append(QString("border-image:url(……);")) );

Answer 3

By using double column for the second entry.

ui->pushButton_2->setStyleSheet(
            "QPushButton{background-color:red;color:white}\
             QPushButton::hover{color:black}");