如何在BB10中滚动实现GRID / TILED图像视图

时间：2012-12-23 08:45:01

标签： c++ blackberry-10

我想实现GRID / TILED图像视图，其中瓦片图像将在下载后即时绘制。我希望能够在其中进行捏合/缩放和其他触摸操作。说，如果我平移视图，将完全或部分地加载和绘制视图上的新图块。我找不到使用任何现有UI控件的方法。此外，那些现有的UI控件不能被子类化，也没有任何paint（）/ onDraw方法（如android中的view / canvas）来覆盖。可能是带有scrollview的imageView可以解决问题。另一个选项可能是使用外部窗口。在这两种情况下，我都不确定如何实现它们或在这些情况下如何处理手势。或者如果有其他方法可以实现它。请给我一些解决它的见解。

1 个答案:

答案 0 :(得分：10)

创建一个CustomImageView，它将从远程加载图像，并将该CustomImageView放入带有GridListLayout的ListView中。您可以使用ListItemProvider类来自定义ListView。我已经为下面的所有必要课程提供了代码。

<强> // main.qml 

import bb.cascades 1.0
import my.library 1.0 //Custom library where CustomImageView and our ListProvider resides

Page {
    content: ScrollView {
        gestureHandlers: [
            PinchHandler {
                onPinchUpdated: {
                    scrollView.zoomToPoint(event.midPointX, event.midPointY, event.pinchRatio)
                }
            }
        ]
        id: scrollView
        scrollViewProperties {
            scrollMode: ScrollMode.None
            pinchToZoomEnabled: true
        }
        ListView {
            overlapTouchPolicy: OverlapTouchPolicy.Allow
            objectName: "listView"
            layout: GridListLayout {
                columnCount: 2
            }
            listItemProvider: CustomImageViewProvider { //Our list item provider
            }
            listItemComponents: [
                ListItemComponent {
                    CustomImageView { //CustomImageView to load image from remote via internet
                    }
                }
            ]
            dataModel: XmlDataModel {
                source: "model/path.xml"
            }
        }
    }
}

// CustomImageView.cpp CustomControl通过互联网加载图像形式远程位置

CustomImageView::CustomImageView(Container *parent) :
    CustomControl(parent) {
    Container *contentContainer = new Container();
    DockLayout *contentLayout = new DockLayout();
    contentContainer->setLayout(contentLayout);

    mItemImage = ImageView::create("");
    mItemImage->setHorizontalAlignment(HorizontalAlignment::Fill);
    mItemImage->setVerticalAlignment(VerticalAlignment::Fill);

    contentContainer->add(mItemImage);

    setRoot(contentContainer);
}

void CustomImageView::updateItem(const QString imagePath) {
    WebServiceRequest *webServiceRequest = new WebServiceRequest(imagePath);
    connect(webServiceRequest, SIGNAL(complete(QByteArray, bool)), this,
            SLOT(onComplete(QByteArray, bool)));
    webServiceRequest->getResponse();
}

void CustomImageView::onComplete(QByteArray data, bool success) {
    if (success) {
        mItemImage->setImage(Image(data));
        mItemImage->setVisible(true);
    } else {
        qDebug() << "Request failed";
    }
}

void CustomImageView::select(bool select) {
}

void CustomImageView::reset(bool selected, bool activated) {
    mItemImage->setVisible(false);
}

void CustomImageView::activate(bool activate) {
}

// WebServiceRequest.cpp CustomImageView用于通过互联网发送图像请求的类

WebServiceRequest::WebServiceRequest(QString url) {
    webServiceUrl = url;
}

WebServiceRequest::~WebServiceRequest() {
}

void WebServiceRequest::getResponse() {
    QNetworkAccessManager* netManager = new QNetworkAccessManager();
    if (!netManager) {
        qDebug() << "Unable to create QNetworkAccessManager!";
        emit complete("Unable to create QNetworkAccessManager!", false);
        return;
    }

    QUrl url(webServiceUrl);
    QNetworkRequest req(url);

    QNetworkReply* ipReply = netManager->get(req);
    connect(ipReply, SIGNAL(finished()), this, SLOT(onReply()));
}

void WebServiceRequest::onReply() {
    QNetworkReply* reply = qobject_cast<QNetworkReply*>(sender());
    QString response;
    bool success = false;
    if (reply) {
        if (reply->error() == QNetworkReply::NoError) {
            int available = reply->bytesAvailable();
            if (available > 0) {
                success = true;
                emit complete(reply->readAll(), success);
            }
        } else {
            response =
                    QString("Error: ") + reply->errorString()
                        + QString(" status:")
                        + reply->attribute(
                                    QNetworkRequest::HttpStatusCodeAttribute).toString();
        }
        reply->deleteLater();
    }
}

// CustomImageViewProvider.cpp 这是我们用于自定义ListView的ListItemProvider 

CustomImageViewProvider::CustomImageViewProvider() {
}

VisualNode * CustomImageViewProvider::createItem(ListView* list,
        const QString &type) {
    CustomImageView *myCustomImageView = new CustomImageView();
    return myCustomImageView;
}

void CustomImageViewProvider::updateItem(ListView* list,
        bb::cascades::VisualNode *listItem, const QString &type,
        const QVariantList &indexPath, const QVariant &data) {
    QVariantMap map = data.value<QVariantMap>();
    CustomImageView *myCustomImageView = static_cast<CustomImageView *>(listItem);
    qDebug() << indexPath;
    QString imagePath = map["path"].toString();
    myCustomImageView->updateItem(imagePath);
}

注册CustomImageView＆amp;在构造函数中创建和设置main.qml的根之前，使用qml的CustomImageViewProvider。这样它们就可以在我们的qml

中找到 
qmlRegisterType < CustomImageView > ("my.library", 1, 0, "CustomImageView");
qmlRegisterType < CustomImageViewProvider > ("my.library", 1, 0, "CustomImageViewProvider");

// Path.xml 所有路径都存储在此文件中，该文件在列表视图中用作DataModel 

<root>
    <image path="http://upload.wikimedia.org/wikipedia/commons/e/eb/A_landscape_in_Peradeniya,_Sri_Lanka.jpg"/>
    <image path="http://lejournaldelaphotographie.com/system/photos/54840/med_fernando-brito_lost-in-the-landscape_1-jpg.jpg"/>
    <image path="http://st.houzz.com/simgs/17713aee00b8b8b7_15-7678/modern-landscape.jpg"/>

    <image path="http://cdn.c.photoshelter.com/img-get/I0000kRJbKDHBT30/s/900/720/Landscape-sunset-15.jpg"/>
    <image path="http://www.cashmoredesign.com/images/large/landscape-5.jpg"/>
    <image path="http://ad009cdnb.archdaily.net/wp-content/uploads/2012/11/50b7d0ddb3fc4b239a0000f2_arteology-atelier-37-2_-atelier37-2_arteologie-34-528x396.jpg"/>

    <image path="http://upload.wikimedia.org/wikipedia/en/e/e8/Berchem,_Nicolaes_~_Landscape_with_Herdsmen_Gathering_Sticks,_early_1650s,_oil_on_panel,_private_collection,_New_York.jpg"/>
    <image path="http://www.taschen.com/media/images/960/teaser_mi_arch_now_landscape_top_1203301047_id_536230.jpg"/>
    <image path="http://lasersandlights.com/images/medium/landscape%20bliss%20spright.jpg"/>

    <image path="http://uploads0.wikipaintings.org/images/pieter-bruegel-the-elder/landscape-with-the-flight-into-egypt-1563.jpg"/>
    <image path="http://middo.me/wp-content/uploads/2012/07/Landscape-with-calm-river-1024x640.jpg"/>
    <image path="http://ad009cdnb.archdaily.net/wp-content/uploads/2012/07/500de84928ba0d609d000038_fort-werk-aan-t-spoel-rietveld-landscape_rob6999kopierl-528x352.jpg"/>

        <image path="http://upload.wikimedia.org/wikipedia/commons/e/eb/A_landscape_in_Peradeniya,_Sri_Lanka.jpg"/>
    <image path="http://lejournaldelaphotographie.com/system/photos/54840/med_fernando-brito_lost-in-the-landscape_1-jpg.jpg"/>
    <image path="http://st.houzz.com/simgs/17713aee00b8b8b7_15-7678/modern-landscape.jpg"/>

    <image path="http://cdn.c.photoshelter.com/img-get/I0000kRJbKDHBT30/s/900/720/Landscape-sunset-15.jpg"/>
    <image path="http://www.cashmoredesign.com/images/large/landscape-5.jpg"/>
    <image path="http://ad009cdnb.archdaily.net/wp-content/uploads/2012/11/50b7d0ddb3fc4b239a0000f2_arteology-atelier-37-2_-atelier37-2_arteologie-34-528x396.jpg"/>

    <image path="http://upload.wikimedia.org/wikipedia/en/e/e8/Berchem,_Nicolaes_~_Landscape_with_Herdsmen_Gathering_Sticks,_early_1650s,_oil_on_panel,_private_collection,_New_York.jpg"/>
    <image path="http://www.taschen.com/media/images/960/teaser_mi_arch_now_landscape_top_1203301047_id_536230.jpg"/>
    <image path="http://lasersandlights.com/images/medium/landscape%20bliss%20spright.jpg"/>

    <image path="http://uploads0.wikipaintings.org/images/pieter-bruegel-the-elder/landscape-with-the-flight-into-egypt-1563.jpg"/>
    <image path="http://middo.me/wp-content/uploads/2012/07/Landscape-with-calm-river-1024x640.jpg"/>
    <image path="http://ad009cdnb.archdaily.net/wp-content/uploads/2012/07/500de84928ba0d609d000038_fort-werk-aan-t-spoel-rietveld-landscape_rob6999kopierl-528x352.jpg"/>

        <image path="http://upload.wikimedia.org/wikipedia/commons/e/eb/A_landscape_in_Peradeniya,_Sri_Lanka.jpg"/>
    <image path="http://lejournaldelaphotographie.com/system/photos/54840/med_fernando-brito_lost-in-the-landscape_1-jpg.jpg"/>
    <image path="http://st.houzz.com/simgs/17713aee00b8b8b7_15-7678/modern-landscape.jpg"/>

    <image path="http://cdn.c.photoshelter.com/img-get/I0000kRJbKDHBT30/s/900/720/Landscape-sunset-15.jpg"/>
    <image path="http://www.cashmoredesign.com/images/large/landscape-5.jpg"/>
    <image path="http://ad009cdnb.archdaily.net/wp-content/uploads/2012/11/50b7d0ddb3fc4b239a0000f2_arteology-atelier-37-2_-atelier37-2_arteologie-34-528x396.jpg"/>

    <image path="http://upload.wikimedia.org/wikipedia/en/e/e8/Berchem,_Nicolaes_~_Landscape_with_Herdsmen_Gathering_Sticks,_early_1650s,_oil_on_panel,_private_collection,_New_York.jpg"/>
    <image path="http://www.taschen.com/media/images/960/teaser_mi_arch_now_landscape_top_1203301047_id_536230.jpg"/>
    <image path="http://lasersandlights.com/images/medium/landscape%20bliss%20spright.jpg"/>

    <image path="http://uploads0.wikipaintings.org/images/pieter-bruegel-the-elder/landscape-with-the-flight-into-egypt-1563.jpg"/>
    <image path="http://middo.me/wp-content/uploads/2012/07/Landscape-with-calm-river-1024x640.jpg"/>
    <image path="http://ad009cdnb.archdaily.net/wp-content/uploads/2012/07/500de84928ba0d609d000038_fort-werk-aan-t-spoel-rietveld-landscape_rob6999kopierl-528x352.jpg"/>

        <image path="http://upload.wikimedia.org/wikipedia/commons/e/eb/A_landscape_in_Peradeniya,_Sri_Lanka.jpg"/>
    <image path="http://lejournaldelaphotographie.com/system/photos/54840/med_fernando-brito_lost-in-the-landscape_1-jpg.jpg"/>
    <image path="http://st.houzz.com/simgs/17713aee00b8b8b7_15-7678/modern-landscape.jpg"/>

    <image path="http://cdn.c.photoshelter.com/img-get/I0000kRJbKDHBT30/s/900/720/Landscape-sunset-15.jpg"/>
    <image path="http://www.cashmoredesign.com/images/large/landscape-5.jpg"/>
    <image path="http://ad009cdnb.archdaily.net/wp-content/uploads/2012/11/50b7d0ddb3fc4b239a0000f2_arteology-atelier-37-2_-atelier37-2_arteologie-34-528x396.jpg"/>

    <image path="http://upload.wikimedia.org/wikipedia/en/e/e8/Berchem,_Nicolaes_~_Landscape_with_Herdsmen_Gathering_Sticks,_early_1650s,_oil_on_panel,_private_collection,_New_York.jpg"/>
    <image path="http://www.taschen.com/media/images/960/teaser_mi_arch_now_landscape_top_1203301047_id_536230.jpg"/>
    <image path="http://lasersandlights.com/images/medium/landscape%20bliss%20spright.jpg"/>

    <image path="http://uploads0.wikipaintings.org/images/pieter-bruegel-the-elder/landscape-with-the-flight-into-egypt-1563.jpg"/>
    <image path="http://middo.me/wp-content/uploads/2012/07/Landscape-with-calm-river-1024x640.jpg"/>
    <image path="http://ad009cdnb.archdaily.net/wp-content/uploads/2012/07/500de84928ba0d609d000038_fort-werk-aan-t-spoel-rietveld-landscape_rob6999kopierl-528x352.jpg"/>
</root>
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