What is the equivalence for QString::arg() in QML

问题:

I'm wondering How I can have a string in QML that will be occupied with some arguments? Some thing like this in Qt:

QString str("%1 %2");
str = str.arg("Number").arg(12);//str = "Number 12"

回答1:

In QML environment, the arg() function already added to the string prototype, so basically you can use the string.arg() in QML just like C++.

There is less documentation about this, but I'm sure it works in Qt 4.7 + QtQuick 1.1

Take at look at the Qt 5 doc : http://qt-project.org/doc/qt-5.0/qtqml/qml-string.html

回答2:

just use :

"foo%1".arg("bar");

回答3:

Arguments are totally unnecessary in this example. In JS, we have simple string concatenation which also supports numbers in between, so you can achieve this with a simple

var str = 'Number' + ' ' + 12

If you really want arguments in non-literal strings, you can just replace the %1 with the replacement. QString::arg (with one argument) is nothing more than the following:

function stringArg(str, arg)
{
    for(var i = 1; i <= 9; ++i)
        if(str.indexOf('%'+i) !== -1)
            return str.replace('%'+i, arg);
    return str;
}

So your code becomes:

var str = "%1 %2"
str = stringArg(str, "Number")
str = stringArg(str, 12)

(Note that this function can only handle %1..%9, while QString::arg can handle up to %99. This requires a bit more logic, since %10 is teated as a %1 in my code. So this is not exactly the same as QString::arg, but it will suffice in the most cases. You could also write a stringArg function taking multiple replacement arguments, but for the simplicity I just wrote this one here.)

回答4:

You might be able to do this with a jQuery plugin:

http://docs.jquery.com/Plugins/Validation/jQuery.format

import "jQuery.js" as JQuery

    Page {

        property string labelStub: "hello {0}"

        Label {
            text: JQuery.validator.format(labelStub, "world")
        }
     }