Kotlin 中的谷歌地图平铺层答案

【问题标题】：Google Maps Tile Layers in KotlinKotlin 中的谷歌地图平铺层
【发布时间】：2019-07-27 06:23:30
【问题描述】：

我正在尝试使用 Google Maps SDK Android 实现 Tile Layers，但官方文档只有 Java 代码示例，而我的项目是在 Kotlin 中。我找不到任何关于如何在 kotlin 中做同样事情的例子。有人知道怎么做吗？

The documentation java example code:

private GoogleMap mMap;

TileProvider tileProvider = new UrlTileProvider(256, 256) {
  @Override
  public URL getTileUrl(int x, int y, int zoom) {

    /* Define the URL pattern for the tile images */
    String s = String.format("http://my.image.server/images/%d/%d/%d.png",
        zoom, x, y);

    if (!checkTileExists(x, y, zoom)) {
      return null;
    }

    try {
      return new URL(s);
    } catch (MalformedURLException e) {
        throw new AssertionError(e);
    }
  }

  /*
   * Check that the tile server supports the requested x, y and zoom.
   * Complete this stub according to the tile range you support.
   * If you support a limited range of tiles at different zoom levels, then you
   * need to define the supported x, y range at each zoom level.
   */
  private boolean checkTileExists(int x, int y, int zoom) {
    int minZoom = 12;
    int maxZoom = 16;

    if ((zoom < minZoom || zoom > maxZoom)) {
      return false;
    }

    return true;
  }
};

TileOverlay tileOverlay = mMap.addTileOverlay(new TileOverlayOptions()
    .tileProvider(tileProvider));

对此的任何帮助将不胜感激

【问题讨论】：

标签： android google-maps kotlin google-maps-android-api-2

【解决方案1】：

给你干杯！

private var mMap:GoogleMap?=null

    val tileProvider = object: UrlTileProvider(256, 256) {
      override fun getTileUrl(x:Int,y:Int,zoom:Int):URL {

        /* Define the URL pattern for the tile images */
        val s = String.format("http://my.image.server/images/%d/%d/%d.png",
            zoom, x, y)

        if (!checkTileExists(x, y, zoom)) {
          return null
        }

        try {
          return URL(s)
        } catch (e:MalformedURLException) {
            throw AssertionError(e)
        }
      }

      /*
       * Check that the tile server supports the requested x, y and zoom.
       * Complete this stub according to the tile range you support.
       * If you support a limited range of tiles at different zoom levels, then you
       * need to define the supported x, y range at each zoom level.
       */
      private fun checkTileExists(x:Int,y:Int,zoom:Int):Boolean {
        val minZoom = 12
        val maxZoom = 16

        if ((zoom < minZoom || zoom > maxZoom)) {
          return false
        }

        return true
      }
    }

    val tileOverlay = mMap!!.addTileOverlay(TileOverlayOptions()
        .tileProvider(tileProvider))

【讨论】：

【解决方案2】：

最后我自己完成了based in this response，我只需要像这样实例化UrlTileProvider抽象类：

val tileProvider: TileProvider = object: UrlTileProvider(256, 256){ 
...
}

最终结果：

val tileProvider: TileProvider = object: UrlTileProvider(256, 256) {
  override fun getTileUrl(x: Int, y: Int, zoom: Int): URL? {

    /* Define the URL pattern for the tile images */
    val s: String = String.format("http://my.image.server/images/%d/%d/%d.png",
      zoom, x, y)

    if (!checkTileExists(x, y, zoom)) {
      return null;
    }

    try {
      return URL(s)
    } catch (e: MalformedURLException) {
      throw AssertionError(e)
    }
  }

  /*
 * Check that the tile server supports the requested x, y and zoom.
 * Complete this stub according to the tile range you support.
 * If you support a limited range of tiles at different zoom levels, then you
 * need to define the supported x, y range at each zoom level.
 */
  private fun checkTileExists(x: Int, y: Int, zoom: Int): Boolean {
    val minZoom: Int = 12
    val maxZoom: Int = 16

    if ((zoom < minZoom || zoom > maxZoom)) {
      return false
    }
    return true
  }
}

val tileOverlay: TileOverlay = mMap.addTileOverlay(TileOverlayOptions()
.tileProvider(tileProvider))

希望它能帮助别人。

【讨论】：