我目前正在创建一个Twitter客户端，作为学习黑莓10开发的一种方式 . 我目前正在尝试为自定义ListView项创建一个上下文菜单，在选择时将在主布局中显示一个对话框 . 但是，我无法从选定的列表项中调用父页面中的任何函数 .
这是我的自定义列表项中的QML：
import bb.cascades 1.0
Container {
property alias avatar: tracker.imageSource
property alias username: txtTweetUser.text
property alias tweetText: txtTweetContent.text
property alias tweetTime: txtTweetTime.text
signal sendReply(string username)
function cout(text) {
console.debug("[DEBUG] " + text);
}
id: itemTweet
preferredWidth: 768;
preferredHeight: 200
// Actions
contextActions: [
ActionSet {
title: "Action Set"
subtitle: "This is an action set."
actions: [
ActionItem {
title: "Reply"
imageSource: "asset:///reply.png"
onTriggered: {
itemTweet.sendReply(txtTweetUser.text);
}
},
ActionItem {
title: "Retweet"
imageSource: "asset:///retweet.png"
},
ActionItem {
title: "Favourite"
imageSource: "asset:///fav.png"
}
]
} // end of ActionSet
] // end of contextActions list
<Layout for the List Item>...
}
}
对于主要的QML文件：
import bb.cascades 1.0
TabbedPane {
id: tabbedPane
showTabsOnActionBar: true
Tab {
id: tabTimeline
title: "Timeline"
imageSource: "asset:///twitter-white.png"
Page {
id: pageTimeline
signal openReply
signal showNewTweet
function cout(text) {
console.debug("[DEBUG] " + text);
}
function showTweetWindow(username) {
pageTimeline.dialogNewTweet.text = username;
pageTimeline.dialogNewTweet.visible = true;
}
// Title bar
titleBar: TitleBar {
visibility: Overlay
title: "Twitter"
acceptAction: ActionItem {
id: btnNewTweet
title: "+"
ActionBar.placement: ActionBarPlacement.OnBar
onTriggered: {
pageTimeline.cout("action selected");
dialogNewTweet.visible = true;
}
}
}
// Main content
content: Container {
layout: AbsoluteLayout {}
Container {
// Listview for the tweets
ListView {
id: lstTweets
objectName: "lstTweets"
// Components to display the rows
listItemComponents: [
ListItemComponent {
id: listItem
type: "listItem"
TweetItem {
tweetText: ListItemData.content
tweetTime: ListItemData.time
avatar: ListItemData.avatar
username: ListItemData.username
onSendReply: {
cout("Reply selected in parent to " + username);
pageTimeline.showTweetWindow(username);
}
}
}
]
onSelectionChanged: {
}
function itemType(data, indexPath) {
if (indexPath.length == 1) {
return "header";
} else {
return "listItem";
}
}
}
}
DialogNewTweet {
id: dialogNewTweet
visible: false
onShowNewTweet: {
dialogNewTweet.visible = true;
}
}
}
// End container
}
}
... <Other tabs> ...
}
因此，当主QML文件收到SendReply信号时，它会调用 showTweetWindow(username) 然后使 dialogNewTweet 可见，但我得到错误 ReferenceError: Can't find variable: pageTimeline . 它's definitely a scope issue, but I can'弄清楚我做错了什么，或者我是否需要对其进行重组 .
1 回答
在这里回答：
https://community.blackberry.com/message/182467#182467
//这里设置了context属性，accountsManager已经创建
qml-> setContextProperty（“accountsManager”，accountsManager）;
//设置列表视图的模型
ListView * accountsListView = root-> findChild <ListView *>（“accountsListView”）;
accountsListView-> setDataModel（accountsManager-> getDataModel（））;
QML代码：Page {
内容：容器{
列表显示 {
id：listView
objectName：“accountsListView”
listItemComponents：[
ListItemComponent {
类型：“listItem”
StandardListItem {
id：accountItem
title：ListItemData.username
contextActions：[
ActionSet {
deleteAction：DeleteActionItem {
Headers ：“删除”
onTriggered：{
//它在这里不起作用，“ReferenceError：找不到变量：accountsManager”
accountsManager.doSometing（）;
}
}
}
]
}
}
]
function itemType（data，indexPath）{
return“listItem”;
}
} // ListView的结尾
} // Container的结尾
行动：[
行动项目 {
Headers ：“添加帐户”
ActionBar.placement：ActionBarPlacement.OnBar
onTriggered：{
//这里运作正常
accountsManager.doSomething（）;
}
}
]
} //页面结尾
另一种方法：
https://community.blackberry.com/message/453794#453794