QML简单程序不运行

Question

我正在尝试运行以下操作，但是当我运行它时没有任何反应。我该如何调试此类问题？

import QtQuick 2.0
import QtQml.Models 2.1



Item{
    id: main
    width: 1500
    height: 1500
    GridView {
        id: root
        width: 1500
        height: 1500
        cellWidth: 200; cellHeight: 200
        visible: true


        model: DelegateModel {
            model: ListModel {
                ListElement {
                    color: "blue"
                }
                ListElement {
                    color: "white"
                }
                ListElement {
                    color: "red"
                }
                ListElement {
                    color: "green"
                }
                ListElement {
                    color: "orange"
                }
                ListElement {
                    color: "yellow"
                }
                ListElement {
                    color: "grey"
                }
            }

            delegate: MouseArea {
                objectName: "mousearea"

                implicitHeight: parent.height
                implicitWidth: parent.width

                Rectangle {
                    anchors.fill: parent
                    color: model.color
                }
                drag{
                    target: parent
                }
            }
        }
    }
}

我打算从这段代码中得到以下内容：在 GridView 内创建几个矩形并向其添加 MouseArea 并尝试在之后拖动它们。我不确定我这里的模型结构是否正确。

编辑：添加 main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    return app.exec();
}

Answer 1

QQmlApplicationEngine 期望有一个 Window 作为根元素，如 docs:

所示

...
Unlike QQuickView, QQmlApplicationEngine does not automatically create a root window. If you are using visual items from Qt Quick, you will need to place them inside of a Window.
...

所以解决方法很简单，把Item改成Window:

main.qml

import QtQuick 2.0
import QtQuick.Window 2.11
import QtQml.Models 2.1

Window{
    visible: true
    id: main
    width: 1500
    height: 1500
    GridView {
        id: root
        width: 1500
        height: 1500
        cellWidth: 200; cellHeight: 200
        visible: true


        model: DelegateModel {
            model: ListModel {
                ListElement {
                    color: "blue"
                }
                ListElement {
                    color: "white"
                }
                ListElement {
                    color: "red"
                }
                ListElement {
                    color: "green"
                }
                ListElement {
                    color: "orange"
                }
                ListElement {
                    color: "yellow"
                }
                ListElement {
                    color: "grey"
                }
            }

            delegate: MouseArea {
                objectName: "mousearea"

                implicitHeight: parent.height
                implicitWidth: parent.width

                Rectangle {
                    anchors.fill: parent
                    color: model.color
                }
                drag{
                    target: parent
                }
            }
        }
    }
}

QML简单程序不运行

QML simple program not running

qt

qml

qt5

qtquick2