本页面介绍了如何以程序化方式访问数据集并设置其地图项的样式，还通过示例演示了如何基于点、多边形和多段线几何图形设置数据地图项的样式。
在对数据集进行数据驱动型样式设置时，系统会基于创建数据集时所用的地理空间数据文件中提供的经纬度坐标来渲染数据地图项。
点数据的样式设置示例
本例演示了如何为基于点几何图形的数据地图项设置样式。
关于数据集
本例中使用的数据集是纽约市中央公园 2018 年松鼠调查的结果。下表摘录自 CSV 格式的调查数据文件，从中我们可以看到：x 和 y 列用于表示地理位置；表中包含 LatLng 列，但在本例中并未使用该列，因为数据集仅在列名为 WKT 时支持 WKT 格式。如需详细了解位置支持的格式，请参阅 CSV 要求。
松鼠普查数据集包含多种不同的数据点，这些数据点与观察到的松鼠毛色和行为相关（请务必水平滚动屏幕，以查看全部内容）。
| X | Y | UniqueSquirrelID | Hectare | Shift | Date | Hectare SquirrelNumber | Age | PrimaryFurColor | HighlightFurColor | CombinationofPrimaryandHighlightColor | Colornotes | Location | AboveGroundSighter Measurement | SpecificLocation | Running | Chasing | Climbing | Eating | Foraging | Other Activities | Kuks | Quaas | Moans | Tailflags | Tailtwitches | Approaches | Indifferent | Runsfrom | OtherInteractions | LatLng |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| -73.9561344937861 | 40.7940823884086 | 37F-PM-1014-03 | 37F | PM | 10142018 | 3 | + | false | false | false | false | false | false | false | false | false | false | false | false | false | POINT (-73.9561344937861 40.7940823884086) | |||||||||
| -73.9688574691102 | 40.7837825208444 | 21B-AM-1019-04 | 21B | AM | 10192018 | 4 | + | false | false | false | false | false | false | false | false | false | false | false | false | false | POINT (-73.9688574691102 40.7837825208444) | |||||||||
| -73.9742811484852 | 40.775533619083 | 11B-PM-1014-08 | 11B | PM | 10142018 | 8 | Gray | Gray+ | Above Ground | 10 | false | true | false | false | false | false | false | false | false | false | false | false | false | POINT (-73.97428114848522 40.775533619083) | ||||||
| -73.9596413903948 | 40.7903128889029 | 32E-PM-1017-14 | 32E | PM | 10172018 | 14 | Adult | Gray | Gray+ | Nothing selected as Primary. Gray selected as Highlights. Made executive adjustments. | false | false | false | true | true | false | false | false | false | false | false | false | true | POINT (-73.9596413903948 40.7903128889029) | ||||||
| -73.9702676472613 | 40.7762126854894 | 13E-AM-1017-05 | 13E | AM | 10172018 | 5 | Adult | Gray | Cinnamon | Gray+Cinnamon | Above Ground | on tree stump | false | false | false | false | true | false | false | false | false | false | false | false | false | POINT (-73.9702676472613 40.7762126854894) | ||||
| -73.9683613516225 | 40.7725908847499 | 11H-AM-1010-03 | 11H | AM | 10102018 | 3 | Adult | Cinnamon | White | Cinnamon+White | false | false | false | false | true | false | false | false | false | true | false | true | false | POINT (-73.9683613516225 40.7725908847499) | ||||||
| -73.9541201789795 | 40.7931811701082 | 36H-AM-1010-02 | 36H | AM | 10102018 | 2 | Adult | Gray | Gray+ | just outside hectare | Ground Plane | FALSE | false | false | false | false | true | false | false | false | false | false | false | false | false | POINT (-73.9541201789795 40.7931811701082) |
设置点数据地图项的样式
本例中的代码采用的方法是，根据 CombinationofPrimaryandHighlightColor 属性（该属性合并了每只松鼠的主要毛色和次要毛色）为每个点的填充颜色和描边颜色设置样式。
Kotlin
private fun styleDatasetsLayer() {
// Create the style factory function.
val styleFactory = FeatureLayer.StyleFactory { feature: Feature ->
// Set default colors to to yellow and point radius to 8.
var fillColor = Color.YELLOW
var strokeColor = Color.YELLOW
var pointRadius = 8F
// Check if the feature is an instance of DatasetFeature.
if (feature is DatasetFeature) {
val furColors: MutableMap<String, String> = feature.getDatasetAttributes()
// Determine CombinationofPrimaryandHighlightColor attribute.
val furColor = furColors!!["CombinationofPrimaryandHighlightColor"]
when (furColor) {
"Black+" -> {
fillColor = Color.BLACK
strokeColor= Color.BLACK
}
"Cinnamon+" -> {
fillColor = -0x750000
strokeColor= -0x750000
}
"Cinnamon+Gray" -> {
fillColor = -0x750000
strokeColor= -0x750000
pointRadius = 6F
}
"Cinnamon+White" -> {
fillColor = -0x750000
strokeColor= Color.WHITE
pointRadius = 6F
}
"Gray+" -> fillColor = Color.GRAY
"Gray+Cinnamon" -> {
fillColor = Color.GRAY
strokeColor= -0x750000
pointRadius = 6F
}
"Gray+Cinnamon, White" -> {
fillColor = Color.LTGRAY
strokeColor= -0x750000
pointRadius = 6F
}
"Gray+White" -> {
fillColor = Color.GRAY
strokeColor= Color.WHITE
pointRadius = 6F
}
}
return@StyleFactory FeatureStyle.Builder()
.fillColor(fillColor)
.strokeColor(strokeColor)
.pointRadius(pointRadius)
.build()
}
return@StyleFactory null
}
// Apply the style factory function to the feature layer.
datasetLayer?.setFeatureStyle(styleFactory)
}
Java
private void styleDatasetsLayer() {
// Create the style factory function.
FeatureLayer.StyleFactory styleFactory = (Feature feature) -> {
// Check if the feature is an instance of DatasetFeature.
if (feature instanceof DatasetFeature) {
// Determine CombinationofPrimaryandHighlightColor attribute.
Map<String, String> furColors = ((DatasetFeature) feature).getDatasetAttributes();
String furColor = furColors.get("CombinationofPrimaryandHighlightColor");
// Set default colors to to yellow and point radius to 8.
int fillColor = Color.YELLOW;
int strokeColor = Color.YELLOW;
int pointRadius = 8;
switch (furColor) {
case "Black+":
fillColor = Color.BLACK;
strokeColor = Color.BLACK;
break;
case "Cinnamon+":
fillColor = 0xff8b0000;
strokeColor = 0xff8b0000;
break;
case "Cinnamon+Gray":
fillColor = 0xff8b0000;
strokeColor = Color.GRAY;
pointRadius = 6;
break;
case "Cinnamon+White":
fillColor = 0xff8b0000;
strokeColor = Color.WHITE;
pointRadius = 6;
break;
case "Gray+":
fillColor = Color.GRAY;
strokeColor = Color.GRAY;
break;
case "Gray+Cinnamon":
fillColor = Color.GRAY;
strokeColor = 0xff8b0000;
pointRadius = 6;
break;
case "Gray+Cinnamon, White":
fillColor = Color.LTGRAY;
strokeColor = 0xff8b0000;
pointRadius = 6;
break;
case "Gray+White":
fillColor = Color.GRAY;
strokeColor = Color.WHITE;
pointRadius = 6;
break;
default:
fillColor = Color.YELLOW;
strokeColor = Color.YELLOW;
pointRadius = 8;
}
return new FeatureStyle.Builder()
.fillColor(fillColor)
.strokeColor(strokeColor)
.pointRadius(pointRadius)
.build();
}
return null;
};
// Apply the style factory function to the feature layer.
datasetLayer.setFeatureStyle(styleFactory);
}
多边形数据的样式设置示例
本例演示了如何为基于多边形几何图形的数据地图项设置样式。
关于数据集
本例中使用的数据集描绘的是纽约市的公园。以下内容摘录自 GeoJSON 数据集文件，显示了一个具有代表性的地图项条目。
{
"type": "Feature",
"properties": {
"jurisdiction": "DPR",
"mapped": "False",
"zipcode": "11356",
"acres": "0.05",
"location": "College Pl., College Pt. Blvd., bet. 11 Ave. and 12 Ave.",
"nys_assembly": "27",
"councildistrict": "19",
"url": "http://www.nycgovparks.org/parks/Q042/",
"typecategory": "Triangle/Plaza",
"us_congress": "14",
"eapply": "Poppenhusen Park",
"parentid": "Q-07",
"gispropnum": "Q042",
"retired": "false",
"communityboard": "407",
"objectid": "6248",
"globalid": "F4810079-CBB9-4BE7-BBFA-B3C0C35D5DE5",
"name311": "Poppenhusen Park",
"department": "Q-07",
"pip_ratable": "true",
"subcategory": "Sitting Area/Triangle/Mall",
"precinct": "109",
"permit": "true",
"acquisitiondate": null,
"omppropid": "Q042",
"gisobjid": "100000301",
"signname": "Poppenhusen Park",
"address": null,
"permitparent": "Q-07",
"class": "PARK",
"nys_senate": "11",
"permitdistrict": "Q-07",
"borough": "Q",
"waterfront": "false"
},
"geometry": {
"type": "MultiPolygon",
"coordinates": [
[
[
[
-73.84575702371716,
40.78796240884273
],
[
-73.84593393292693,
40.78796857347548
],
[
-73.84577256469657,
40.787651355629556
],
[
-73.84575702371716,
40.78796240884273
]
]
]
]
}
},
设置多边形数据地图项的样式
本例中的代码将特殊颜色应用于 typecategory 为“Undeveloped”或“Parkway”的数据地图项，并将所有其他地图项的颜色设为绿色。
Kotlin
private fun styleDatasetsLayer() {
// Create the style factory function.
val styleFactory = FeatureLayer.StyleFactory { feature: Feature ->
// Check if the feature is an instance of DatasetFeature.
if (feature is DatasetFeature) {
// Determine the value of the typecategory attribute.
val typeCategories: MutableMap<String, String> = feature.getDatasetAttributes()
val typeCategory = typeCategories!!["typecategory"]
// Set default colors to green.
var fillColor = 0x4000ff00
var strokeColor = 0xff00ff00
when (typeCategory) {
"Undeveloped" -> {
// Color undeveloped areas blue.
fillColor = 0x400000ff
strokeColor = 0x400000ff
}
"Parkway" -> {
// Color parkway areas red.
fillColor = 0x40ff0000
strokeColor = 0x40ff0000
}
else -> {
// Color all other areas green.
fillColor = 0x4000ff00
strokeColor = 0xff00ff00
}
}
return@StyleFactory FeatureStyle.Builder()
.fillColor(fillColor)
.strokeColor(strokeColor)
.strokeWidth(2F)
.build()
}
return@StyleFactory null
}
// Apply the style factory function to the feature layer.
datasetLayer?.setFeatureStyle(styleFactory)
}
Java
private void styleDatasetsLayer() {
// Create the style factory function.
FeatureLayer.StyleFactory styleFactory = (Feature feature) -> {
// Check if the feature is an instance of DatasetFeature.
if (feature instanceof DatasetFeature) {
// Determine the value of the typecategory attribute.
Map<String, String> typeCategories = ((DatasetFeature) feature).getDatasetAttributes();
String typeCategory = typeCategories.get("typecategory");
// Set default colors to green.
int fillColor = 0x4000ff00;
int strokeColor = 0xff00ff00;
switch (typeCategory) {
case "Undeveloped":
// Color undeveloped areas blue.
fillColor = 0x400000ff;
strokeColor = 0xff0000ff;
break;
case "Parkway":
// Color parkway areas red.
fillColor = 0x40ff0000;
strokeColor = 0xffff0000;
break;
default:
// Color all other areas green.
fillColor = 0x4000ff00;
strokeColor = 0xff00ff00;
}
return new FeatureStyle.Builder()
.fillColor(fillColor)
.strokeColor(strokeColor)
.strokeWidth(2)
.build();
}
return null;
};
// Apply the style factory function to the feature layer.
datasetLayer.setFeatureStyle(styleFactory);
}
多段线数据的样式设置示例
本例演示了如何为基于多段线几何图形的数据地图项设置样式。
关于数据集
本例中使用的数据集描绘的是西雅图地区的桥梁。以下内容摘录自 GeoJSON 数据集文件，显示了一个具有代表性的地图项条目。
{
"type": "Feature",
"properties": {
"OBJECTID": 1,
"COMPTYPE": 66,
"COMPKEY": 515774,
"HANSEGKEY": 489781,
"UNITID": "BRG-935",
"UNITTYPE": " ",
"BRGUNITID": "BRG-935",
"UNITDESC_BRG": "YALE AVE BR REV LANE OC ",
"UNITDESC_SEG": "HOWELL ST ON RP BETWEEN HOWELL ST AND I5 SB ",
"INSTDATE": null,
"EXPDATE": null,
"STATUS": " ",
"STATUSDT": null,
"CONDITION": " ",
"CONDDT": null,
"OWN": " ",
"LSTVERIFY": null,
"MAINTBY": " ",
"ADDBY": "GARCIAA",
"ADDDTTM": "2010-01-21T00:00:00Z",
"MODBY": null,
"MODDTTM": null,
"BR_NBR": 935,
"BR_CODE": " 935",
"BR_TYPE": "ST",
"BR_NAME": "YALE AVE BR REV LANE OC",
"BR_FACILITIES": "YALE AVE-SR 5 ON RAMP",
"BR_FEATURES": "SR 5 REV LANE",
"BR_RATING": 0,
"BR_INSET": 1,
"BR_GEO": "DT",
"BR_OWNER": "DOT",
"BR_OWNER_NAME": "State of Washington",
"GEOBASID": 0,
"XGEOBASID": 0,
"GISSEGKEY": 489781,
"EARTHQUAKE_RESPONSE_TEAM": " ",
"SHAPE_Length": 220.11891836147655
},
"geometry": {
"type": "LineString",
"coordinates": [
[
-122.329201929090928,
47.616910448708538
],
[
-122.329206483407461,
47.616976719821004
],
[
-122.32921802149356,
47.617042137515213
],
[
-122.329236413912909,
47.617105967923777
],
[
-122.329261454336034,
47.617167494985758
],
[
-122.329292861855023,
47.617226028479571
],
[
-122.329330284134699,
47.617280911766009
],
[
-122.329373301365223,
47.617331529154569
],
[
-122.329421430971635,
47.617377312810319
],
[
-122.329474133027375,
47.617417749124023
],
[
-122.32953081631139,
47.617452384473893
]
]
}
},
设置多段线数据地图项的样式
以下代码段会将相同的样式直接应用于所有数据地图项。
Kotlin
private fun styleDatasetsLayer() {
// Create the style factory function.
val styleFactory = FeatureLayer.StyleFactory { feature: Feature ->
// Check if the feature is an instance of DatasetFeature.
if (feature is DatasetFeature) {
return@StyleFactory FeatureStyle.Builder()
// Define a style with green stroke with a width of 4.
.strokeColor(0xff00ff00.toInt())
.strokeWidth(4F)
.build()
}
return@StyleFactory null
}
// Apply the style factory function to the feature layer.
datasetLayer?.setFeatureStyle(styleFactory)
}
Java
private void styleDatasetsLayer() {
// Create the style factory function.
FeatureLayer.StyleFactory styleFactory = (Feature feature) -> {
// Check if the feature is an instance of DatasetFeature.
if (feature instanceof DatasetFeature) {
return new FeatureStyle.Builder()
// Define a style with green stroke with a width of 4.
.strokeColor(0xff00ff00)
.strokeWidth(4)
.build();
}
return null;
};
// Apply the style factory function to the feature layer.
datasetLayer.setFeatureStyle(styleFactory);
}