完善气泡窗口和DIvIcon的内容设置问题

src/core/layer/GeoJsonLayer.js

@@ -75,6 +75,12 @@ class GeoJsonLayer extends Layer {
     }
   }
 
+  /**
+   *
+   * @param method
+   * @param context
+   * @returns {GeoJsonLayer}
+   */
   eachOverlay(method, context) {
     if (this._delegate) {
       this._delegate.then(dataSource => {

src/core/overlay/base/DivIcon.js

@@ -51,11 +51,18 @@ class DivIcon extends Overlay {
     if (content && typeof content === 'string') {
       this._delegate.innerHTML = content
     } else if (content && content instanceof Element) {
+      while (this._delegate.hasChildNodes()) {
+        this._delegate.removeChild(this._delegate.firstChild)
+      }
       this._delegate.appendChild(content)
     }
     return this
   }
 
+  get content() {
+    return this._content
+  }
+
   /**
    * Updates style
    * @param style

src/core/transform/Transform.js

@@ -17,7 +17,8 @@ class Transform {
    */
   static transformCartesianToWGS84(cartesian) {
     if (cartesian) {
-      let cartographic = Cesium.Cartographic.fromCartesian(cartesian)
+      let ellipsoid = Cesium.Ellipsoid.WGS84
+      let cartographic = ellipsoid.cartesianToCartographic(cartesian)
       return new Position(
         Cesium.Math.toDegrees(cartographic.longitude),
         Cesium.Math.toDegrees(cartographic.latitude),

src/core/viewer/Viewer.js

@@ -420,6 +420,15 @@ class Viewer {
     return this
   }
 
+  /**
+   * Removes terrain
+   * @returns {Viewer}
+   */
+  removeTerrain() {
+    this._delegate.terrainProvider = new Cesium.EllipsoidTerrainProvider()
+    return this
+  }
+
   /**
    *
    * @param layerGroup
@@ -641,6 +650,7 @@ class Viewer {
    */
   destroy() {
     this._delegate.destroy()
+    this._delegate = undefined
     return this
   }
 

src/core/widget/Widget.js

@@ -123,6 +123,9 @@ class Widget {
     if (content && typeof content === 'string') {
       this._wrapper.innerHTML = content
     } else if (content && content instanceof Element) {
+      while (this._wrapper.hasChildNodes()) {
+        this._wrapper.removeChild(this._wrapper.firstChild)
+      }
       this._wrapper.appendChild(content)
     }
     return this