The view status includes information on the loading state of layers and whether layers are visible at a given scale. You might change how a layer is displayed in a layer list to communicate whether it is being viewed in the map. For example, you could show a loading spinner next to its name when the view status is LOADING, grey out the name when NOT_VISIBLE or OUT_OF_SCALE, show the name normally when ACTIVE, or with a warning or error icon when the status is WARNING or ERROR.
How to use the sample
Click "Load Layer" to add a feature layer to the map. The current view status of the layer will display at the top of the sample. Zoom in and out of the map and note the layer disappears when the map is scaled outside of its min and max scale range. Control the layer's visibility with the "Layer visible" checkbox. If you disconnect your device from the network and pan around the map, a warning alert will display. Reconnect to the network to remove the warning. The layer's current view status will update accordingly as you carry out these actions.
How it works
Create an ArcGISMap with some operational layers.
Set the map on a MapView.
Add a LayerViewStateChangedListener to the map view to capture LayerViewStateChangedEvent.
Get the current view status with event.getLayerViewStatus().
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/*
* Copyright 2017 Esri.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/package com.esri.samples.display_layer_view_state;
import java.util.ArrayList;
import java.util.EnumSet;
import java.util.List;
import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.scene.control.Button;
import javafx.scene.control.CheckBox;
import javafx.scene.control.Label;
import javafx.scene.layout.Background;
import javafx.scene.layout.BackgroundFill;
import javafx.scene.layout.CornerRadii;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Paint;
import javafx.stage.Stage;
import com.esri.arcgisruntime.ArcGISRuntimeEnvironment;
import com.esri.arcgisruntime.ArcGISRuntimeException;
import com.esri.arcgisruntime.geometry.Point;
import com.esri.arcgisruntime.geometry.SpatialReferences;
import com.esri.arcgisruntime.layers.FeatureLayer;
import com.esri.arcgisruntime.loadable.LoadStatus;
import com.esri.arcgisruntime.mapping.ArcGISMap;
import com.esri.arcgisruntime.mapping.BasemapStyle;
import com.esri.arcgisruntime.mapping.Viewpoint;
import com.esri.arcgisruntime.mapping.view.LayerViewStatus;
import com.esri.arcgisruntime.mapping.view.MapView;
import com.esri.arcgisruntime.portal.Portal;
import com.esri.arcgisruntime.portal.PortalItem;
publicclassDisplayLayerViewStateSampleextendsApplication{
private MapView mapView;
private FeatureLayer featureLayer;
@Overridepublicvoidstart(Stage stage){
try {
// create the stack pane and the application scene StackPane stackPane = new StackPane();
Scene scene = new Scene(stackPane);
scene.getStylesheets().add(getClass().getResource("/display_layer_view_state/style.css").toExternalForm());
// set a title, size, and add the scene to the stage stage.setTitle("Display Layer View State Sample");
stage.setWidth(800);
stage.setHeight(700);
stage.setScene(scene);
stage.show();
// authentication with an API key or named user is required to access basemaps and other location services String yourAPIKey = System.getProperty("apiKey");
ArcGISRuntimeEnvironment.setApiKey(yourAPIKey);
// create a map with the topographic basemap style ArcGISMap map = new ArcGISMap(BasemapStyle.ARCGIS_TOPOGRAPHIC);
// create a map view and set the map to it mapView = new MapView();
mapView.setMap(map);
// set the initial viewpoint for the map view mapView.setViewpoint(new Viewpoint(new Point(-11e6, 45e5, SpatialReferences.getWebMercator()), 40000000));
// create a label to display the view status Label layerViewStatusLabel = new Label("Current view status: ");
// create a checkbox UI that toggles the visibility of the feature layer CheckBox visibilityCheckBox = new CheckBox();
visibilityCheckBox.setText("Layer visible");
visibilityCheckBox.setSelected(true);
visibilityCheckBox.setDisable(true);
visibilityCheckBox.setOnAction(event -> featureLayer.setVisible(visibilityCheckBox.isSelected()));
// create a button and a listener to load a feature layer Button loadLayerButton = new Button("Load Layer");
loadLayerButton.setOnAction(event -> {
// disable the checkbox when loading/reloading the feature layer, and, if it exists, remove it by clearing the map's operational layersif (!visibilityCheckBox.isDisabled()) {
visibilityCheckBox.setDisable(true);
}
if (featureLayer != null) {
map.getOperationalLayers().clear();
}
// create a new feature layer from a portal itemfinal PortalItem portalItem = new PortalItem(new Portal("https://runtime.maps.arcgis.com/"),
"b8f4033069f141729ffb298b7418b653");
featureLayer = new FeatureLayer(portalItem, 0);
// set a minimum and a maximum scale for the visibility of the feature layer featureLayer.setMinScale(40000000);
featureLayer.setMaxScale(4000000);
// add the feature layer to the map map.getOperationalLayers().add(featureLayer);
// enable UI interactions once the feature layer has loaded featureLayer.addDoneLoadingListener(() -> {
if (featureLayer.getLoadStatus() == LoadStatus.LOADED) {
visibilityCheckBox.setDisable(false);
featureLayer.setVisible(visibilityCheckBox.isSelected());
loadLayerButton.setText("Reload Layer");
} else {
new Alert(Alert.AlertType.ERROR, "Feature layer failed to load").show();
}
});
});
// create a listener that fires every time a layer's view status changes mapView.addLayerViewStateChangedListener(statusChangeEvent -> {
// check the layer whose state has changed is the feature layerif (statusChangeEvent.getLayer() == featureLayer) {
// get the layer's view status and display the status EnumSet<LayerViewStatus> layerViewStatus = statusChangeEvent.getLayerViewStatus();
List<String> stringList = new ArrayList<>();
if (layerViewStatus.contains(LayerViewStatus.ACTIVE)) {
stringList.add("Active");
}
if (layerViewStatus.contains(LayerViewStatus.ERROR)) {
stringList.add("Error");
}
if (layerViewStatus.contains(LayerViewStatus.LOADING)) {
stringList.add("Loading");
}
if (layerViewStatus.contains(LayerViewStatus.NOT_VISIBLE)) {
stringList.add("Not Visible");
}
if (layerViewStatus.contains(LayerViewStatus.OUT_OF_SCALE)) {
stringList.add("Out of Scale");
}
if (layerViewStatus.contains(LayerViewStatus.WARNING)) {
stringList.add("Warning");
}
layerViewStatusLabel.setText("Current view status: " + String.join(", ", stringList));
// show an alert if a warning is detected from the state change ArcGISRuntimeException statusError = statusChangeEvent.getError();
if (statusError != null) {
new Alert(Alert.AlertType.ERROR, "Unable to update layer view status").show();
}
}
});
// create a control panel and add the label, checkbox and button UI components VBox controlsVBox = new VBox(15);
controlsVBox.setBackground(new Background(new BackgroundFill(Paint.valueOf("rgba(0,0,0,0.5)"), CornerRadii.EMPTY,
Insets.EMPTY)));
controlsVBox.setPadding(new Insets(10.0));
controlsVBox.setMaxSize(320, 120);
controlsVBox.getStyleClass().add("panel-region");
controlsVBox.getChildren().addAll(layerViewStatusLabel, visibilityCheckBox, loadLayerButton);
// add the map view and control panel to the stack pane stackPane.getChildren().addAll(mapView, controlsVBox);
StackPane.setAlignment(controlsVBox, Pos.TOP_LEFT);
StackPane.setMargin(controlsVBox, new Insets(10, 0, 0, 10));
} catch (Exception e) {
// on any error, display the stack trace e.printStackTrace();
}
}
/**
* Stops and releases all resources used in application.
*/@Overridepublicvoidstop(){
if (mapView != null) {
mapView.dispose();
}
}
/**
* Opens and runs application.
*
* @param args arguments passed to this application
*/publicstaticvoidmain(String[] args){
Application.launch(args);
}
}