Problem with QML Map tiles updating

[PavloPrykhodko]

Hi everyone. I have a solution to load on disk selected map area and than use it as cached map. I want to make tiles visible after downloading. I decided to call window with proposal to reload Map. Programm also supports choosing of Map providers, so Map is created dynamically(using Loader) each time when plugin changed or propose to reload submitted. The problem is that if plugin wasn't changed to reload plugin parameters I need to create Map object twice, with empty plugin name and current provider. Look at reloadMap() method. If there some method exists to solve it less askew?

Item {
id: item

// Just to use shorter names of dynamic components
property alias customMap: customMapLoader.item
property alias cacheMapArea: cacheMapAreaLoader.item
property alias cacheWindow: cacheWindowLoader.item
property alias mapUpdaterDialog: mapUpdaterDialogLoader.item

property var controlsHeight: 20

property bool cachingFinished: !cacheManager.isDownloading

function cache() {
    if (cacheMapArea.firstPoint !== undefined && cacheMapArea.lastPoint !== undefined) {
        cacheManager.setZoomRange(cacheWindow.zoomFrom, cacheWindow.zoomTo)
        cacheManager.setCacheCoordinates(cacheMapArea.firstPoint, cacheMapArea.lastPoint)
        cacheManager.cacheMap()
    }
}

visible: true

//choose plugins
ComboBox {
    id: plugins

    function reloadMap() {
        if (currentText === mapPlugin.name) {
            // setting empty plugin just to reload tiles reading if provider wasn't changed
            customMapLoader.source = ""
            customMapLoader.source = "CustomMap.qml"
            mapPlugin.name = ""
            customMap.plugin = mapPlugin
        }
        customMapLoader.source = ""
        customMapLoader.source = "CustomMap.qml"
        mapPlugin.name = currentText
        customMap.plugin = mapPlugin
    }

    model: ["osm", "esri"]

    width: item.width / 2
    height: controlsHeight

    onCurrentTextChanged: { reloadMap() }

    Plugin { // offline cache implemented only for osm
        id: mapPlugin

        onNameChanged: {
            cacheButton.enabled = true
            cacheManager.setProvider(name);
        }

        // OSM parameters:
        PluginParameter {
            name: 'osm.mapping.cache.directory'
            value: cacheManager.appCachePath + "osm/"
        }
        PluginParameter {
            name: 'osm.mapping.cache.disk.cost_strategy'
            value: "unitary"
        }
        PluginParameter {
            name: 'osm.mapping.cache.disk.size'
            value: 10000000 // ~ 60 GB
        }
    }
}

Button {
    id: cacheButton

    parent: item
    text: qsTr("Cache area")

    width: item.width / 4
    height: controlsHeight
    x: plugins.x + plugins.width
    y: 0

    onClicked: {
        cacheWindowLoader.source = ""
        cacheWindowLoader.source = "CacheWindow.qml"

        cacheMapAreaLoader.source = ""                  // delete previous area
        cacheMapAreaLoader.source = "CacheMapArea.qml"  // create new area

        cacheWindow.applyClicked.connect(cache)
        cacheWindow.stopClicked.connect(cacheManager.stopCaching)
        cacheWindow.resetClicked.connect(cacheMapArea.resetSelection)
    }
}

ProgressBar {
    property int progress: cacheManager.total != 0 ? cacheManager.downloaded / cacheManager.total * 100 : 0

    width: item.width / 4
    height: controlsHeight
    x: cacheButton.width + cacheButton.x

    minimumValue: 0
    maximumValue: 100
    value: cacheManager.isDownloading === true ? progress : 0

    Label { x: (parent.width - width) / 2; y: (parent.height - height) / 2; text: cacheManager.status }
}

Loader {
    id: customMapLoader

    parent: item
    anchors { fill: parent; topMargin: controlsHeight }
}

Loader { // to open window
    id: cacheWindowLoader

    function deleteObject() { source = "" } // to create connection

    parent: item
    anchors { fill: parent; topMargin: plugins.height }

    onLoaded: { customMap.mapDestroyed.connect(deleteObject) }
}

Loader {
    id: cacheMapAreaLoader

    function deleteObject() { source = "" } // to create connection

    parent: item
    anchors { fill: parent; topMargin: 20 }

    onLoaded: {
        cacheMapArea.parent = customMap
        customMap.mapDestroyed.connect(deleteObject)
    }
}

Loader {
    id: mapUpdaterDialogLoader

    function deleteObject() { source = "" } // to create connection

    parent: item
    anchors { fill: parent; topMargin: 20 }

    onLoaded: {
        customMap.mapDestroyed.connect(deleteObject)
    }
}

onCachingFinishedChanged: {
    if (cachingFinished === true && cacheManager.downloaded > 0) {
        mapUpdaterDialogLoader.source = ""
        mapUpdaterDialogLoader.source = "MapUpdaterDialog.qml"

        mapUpdaterDialog.yes.connect(plugins.reloadMap)
        mapUpdaterDialog.no.connect(mapUpdaterDialogLoader.deleteObject)
    }
}

}