我正在QT Docu中阅读此功能
它说
QValidator::State QAbstractSpinBox::validate(QString &input, int &pos) const [virtual]
QAbstractSpinBox调用此虚拟函数以确定 input 是否有效。 pos 参数指示字符串中的位置。在各个子类中重新实现。
我有一个奇怪的问题,因为我不太了解这份文件。这里的 input 是一个字符串,我们确定 input 是否有效。那么,为什么我们需要字符串中的位置呢?我以为 pos 在这里是字符串的长度,但是当我调试时,它不是真的。那么 pos 是什么意思?
更新:
感谢@mohabouje。在我的情况下,我使用从QAbstractSpinBox
继承的类,我重写了此方法,并希望在更改字符串后对其进行验证。我如何更新此pos
进行验证?
QValidator::State MySpinBox::validate( QString &input, int &pos ) const
{
QString pureValue = stripped( input, &tmpPos, prefix(), suffix() ); //this is my function, i just want to remove also prefix and suffix
//I want to add group separator into the pureValue and validate it after that
//I want to add group separator here, not in the constructor with setGroupSeparatorShown(true);
//When i add group separator here, the separator appears simultaneously when we type
//When i set setGroupSeparatorShown(true) in the constructor, it appears after we finish editing and move to another thing (this element loses focus)
pureValue.insert(3, locale().groupSeparator());
input = pureValue;
// I think now 'pos' has changed, how could I update 'pos' to call the following function?
QValidator::State state = QDoubleSpinBox::validate( input, pos );
return state;
}
答案 0 :(得分:1)
我很好奇底层的实现。我检查了github中的源代码。
QVariant QDoubleSpinBoxPrivate::validateAndInterpret(QString &input, int &pos,
QValidator::State &state) const
{
if (cachedText == input && !input.isEmpty()) {
state = cachedState;
QSBDEBUG() << "cachedText was '" << cachedText << "' state was "
<< state << " and value was " << cachedValue;
return cachedValue;
}
const double max = maximum.toDouble();
const double min = minimum.toDouble();
QString copy = stripped(input, &pos);
QSBDEBUG() << "input" << input << "copy" << copy;
int len = copy.size();
...
}
参数在称为stripped
的私有函数中使用。这是源代码:
QString QAbstractSpinBoxPrivate::stripped(const QString &t, int *pos) const
{
QString text = t;
if (specialValueText.size() == 0 || text != specialValueText) {
int from = 0;
int size = text.size();
bool changed = false;
if (prefix.size() && text.startsWith(prefix)) {
from += prefix.size();
size -= from;
changed = true;
}
if (suffix.size() && text.endsWith(suffix)) {
size -= suffix.size();
changed = true;
}
if (changed)
text = text.mid(from, size);
}
const int s = text.size();
text = text.trimmed();
if (pos)
(*pos) -= (s - text.size());
return text;
}
因此,如果我正确理解,给定字符串和前缀/后缀配置,该函数将使用字符串并计算要验证的数据的实际大小,而忽略前缀和后缀。
该函数返回已验证的数据,可以对其进行分析以计算数值。
pos的原始值,该函数减去要验证的文本大小与执行修剪操作后的文本大小之差。