![](/img/trans.png)
[英]QML ScrollBar/ListView sensitivity for mouse wheel. How to adjust
[英]Qml: ScrollView containing a ListView does not adjust ScrollBar handle
我正在嘗試根據需要將垂直滾動條添加到 ListView。 有人告訴我,最好的方法是將 ListView 放在 ScrollView 中,而不是將滾動條插入 ListView(就像在這個問題中),因為這樣可以提高 GPU 的效率。
我插入了它,如下例所示 - 但無論我嘗試什么,如果滾動條顯示,它的手柄總是占據整個高度,當然不會移動。
我希望你可以看看我的示例並給我一個建議,為什么滾動條沒有正確顯示。
代碼中有注釋解釋我做了什么以及為什么。
import QtQuick 2.0
import QtQuick.Controls 1.4
import QtQuick.Controls.Styles 1.4
Item
{
readonly property int parentWidth: 280
readonly property int parentMaxHeight: 400
// Main reason for doing this - the items are custom objects and
// their width does not automatically adjust for having the scroll bar or not
// But also, to set scroll bars because Qt.ScrollBarAsNeeded makes them not show
property bool scrollBarVisible: myListView.contentHeight > myListView.height
width: parentWidth
height: parentMaxHeight
Rectangle
{
id: myMenuRect
anchors.rightMargin: 2
anchors.leftMargin: 2
anchors.bottomMargin: 4
anchors.topMargin: 4
width: parentWidth
height: myListView.height
radius: 10
z: 2
color: "red" // Adding this to show why the height of the rectangle must match the listview
}
ScrollView
{
id: myScrollView
parent: myMenuRect
anchors.fill: parent
anchors.topMargin: 5
anchors.bottomMargin: 5
anchors.rightMargin: 5
frameVisible: false
// I have tried to set implicitHeight in many different ways,
// no matter what I do the scroll bar handle occupies the enire bar and doesn't move
// The Qt.ScrollBarAsNeeded didn't work... so I did this
verticalScrollBarPolicy: scrollBarVisible ? Qt.ScrollBarAlwaysOn : Qt.ScrollBarAlwaysOff
// Adding colors on scrollbar to show which part is showing
style: ScrollViewStyle
{
handle: Rectangle
{
implicitWidth: 10
implicitHeight: 2
radius: 10
anchors.leftMargin: 1
anchors.left: parent.left
color: "yellow"
}
scrollBarBackground: Rectangle
{
implicitWidth: 12
anchors.right: parent.right
color: "green"
}
}
ListView
{
id: myListView
parent: myScrollView
model: wifiComboListModel
focus: true
clip: true
interactive: false
width: parent.width
// I am trying to tell my view to take the minimum space it needs that is below
// a certain height. Ignore the "myListView." prefixes here, I know they are not needed but
// make it easier to move this outside if needed
height: (myListView.contentHeight > 0 ?
(myListView.contentHeight < parentMaxHeight ?
myListView.contentHeight : parentMaxHeight) : 0)
// I made this as simple as possible, without affecting "quality"
delegate: Text
{
text: _comboBoxText
height: 70
width: parent.width - 20
}
}
ListModel
{
id: wifiComboListModel
}
// I want to populate my model from outside, not be static. Not sure if this affects the bars
function populateComboBoxListModel()
{
wifiComboListModel.clear();
for (var itemIndex = 0; itemIndex < listItems.length; itemIndex++)
{
wifiComboListModel.append
({
_id: itemIndex,
_comboBoxText: listItems[itemIndex]
});
}
}
Component.onCompleted:
{
populateComboBoxListModel();
}
property var listItems: [
"This",
"annoying",
"list",
"view",
"does",
"not behave the way",
"I expect.",
"I",
"tried many",
"things,",
"now I am",
"begging for your",
"help",
"."
]
}
您在 myMenuRect 中有一個高度綁定循環。 這是因為 myMenuRect 取決於列表視圖的高度,反之亦然。 修復后它似乎工作:
import QtQuick 2.0
import QtQuick.Controls 1.4
ApplicationWindow
{
readonly property int parentWidth: 280
readonly property int parentMaxHeight: 400
visible: true
// Main reason for doing this - the items are custom objects and
// their width does not automatically adjust for having the scroll bar or not
// But also, to set scroll bars because Qt.ScrollBarAsNeeded makes them not show
property bool scrollBarVisible: myListView.contentHeight > myListView.height
width: parentWidth
height: parentMaxHeight
Rectangle
{
id: myMenuRect
anchors.rightMargin: 2
anchors.leftMargin: 2
anchors.bottomMargin: 4
anchors.topMargin: 4
width: parentWidth
height: parentMaxHeight
radius: 10
z: 2
}
ScrollView
{
id: myScrollView
parent: myMenuRect
anchors.fill: parent
anchors.topMargin: 5
anchors.bottomMargin: 5
anchors.rightMargin: 5
frameVisible: false
// I have tried to set implicitHeight in many different ways,
// no matter what I do the scroll bar handle occupies the enire bar and doesn't move
// The Qt.ScrollBarAsNeeded didn't work... so I did this
verticalScrollBarPolicy: scrollBarVisible ? Qt.ScrollBarAlwaysOn : Qt.ScrollBarAlwaysOff
ListView
{
id: myListView
model: wifiComboListModel
focus: true
clip: true
interactive: false
width: parent.width
// I am trying to tell my view to take the minimum space it needs that is below
// a certain height. Ignore the "myListView." prefixes here, I know they are not needed but
// make it easier to move this outside if needed
height: (myListView.contentHeight > 0 ?
(myListView.contentHeight < parentMaxHeight ?
myListView.contentHeight : parentMaxHeight) : 0)
// I made this as simple as possible, without affecting "quality"
delegate: Text
{
text: _comboBoxText
height: 70
width: parent.width - 20
}
}
}
ListModel
{
id: wifiComboListModel
}
// I want to populate my model from outside, not be static. Not sure if this affects the bars
function populateComboBoxListModel()
{
wifiComboListModel.clear();
for (var itemIndex = 0; itemIndex < listItems.length; itemIndex++)
{
wifiComboListModel.append
({
_id: itemIndex,
_comboBoxText: listItems[itemIndex]
});
}
}
Component.onCompleted:
{
populateComboBoxListModel();
}
property var listItems: [
"This",
"annoying",
"list",
"view",
"does",
"not behave the way",
"I expect.",
"I",
"tried many",
"things,",
"now I am",
"begging for your",
"help",
"."
]
}
我的 ScrollView 沒有表現的原因是為人父母:)
問題:即使我在 ListView 中設置了父級,似乎也不需要:
ListView
{
parent: myScrollView
我必須做的事情實際上是將 ListView 嵌套在 ScrollView 中。
ScrollView
{
id: myScrollView
parent: myMenuRect
anchors.fill: parent
ListView
{
id: myListView
model: wifiComboListModel
我認為“父”屬性可能不適用於所有控件,並且將來會記住這一點。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.