在 getTileUrl 中为 Maps Tile Android 添加授权 header

Question

我想在为 Google 地图 API 创建 TileOverlay 时访问一些自定义地图图块。

所以这是我当前的代码：

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

            String url = String.format("https://api.mycustommaps.com/v1/%d/%d/%d.jpg", z, x, y);

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

            try {
                URL tileUrl = new URL(url);
                tileUrl.openConnection().addRequestProperty("Authorization", LOGIN_TOKEN);
                return tileUrl;
            } catch (MalformedURLException e) {
                e.printStackTrance();
            } catch (IOException e) {
                e.printStackTrance();
            }
            return null;
        }
    };

由于连接returns 401 已授权，我无法访问磁贴。我如何通过授权 header 让 url 知道我有权访问这些磁贴？

Answer 1

你必须实现 "TileProvider" 接口，而不是 URLTileProvider（因为你必须自己检索图块，URL 是不够的。 https://developers.google.com/android/reference/com/google/android/gms/maps/model/TileProvider 如您所见，有一个注意事项：

Calls to methods in this interface might be made from multiple threads so implementations of this interface must be threadsafe.

并且您必须实现一个方法：

abstract Tile getTile(int x, int y, int zoom)

现在是你下载磁贴的工作了，我已经为本地文件完成了，所以我只是在这里写一些可能需要更多改进和测试的代码：

@Override
public Tile getTile(int x, int y, int zoom) {
  String url = String.format("https://api.mycustommaps.com/v1/%d/%d/%d.jpg", z, x, y);

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

  try {
    URL tileUrl = new URL(url);
    //Download the PNG as byte[], I suggest using OkHTTP library or see next code! 
    final byte[] data = downloadData(tileUrl);
    final int height = tileheight;
    final int width =  tilewidth;
    if (data != null) {
        if (BuildConfig.DEBUG)Log.d(TAG, "Cache hit for tile " + key);
           return new Tile(width, height, data);
    }
    //In this case error, maybe return a placeholder tile or TileProvider.NO_TILE

  } catch (MalformedURLException e) {
     e.printStackTrance();
  } catch (IOException e) {
       e.printStackTrance();
  }
}

下载：

byte[] downloadData(URL url){ 
ByteArrayOutputStream baos = new ByteArrayOutputStream();
InputStream is = null;
try {
  tileUrl.openConnection().addRequestProperty("Authorization", LOGIN_TOKEN);
  is = url.openStream();
  byte[] byteChunk = new byte[4096]; // Or whatever size you want to read in at a time.
  int n;

  while ( (n = is.read(byteChunk)) > 0 ) {
    baos.write(byteChunk, 0, n);
  }
}
catch (IOException e) {
  System.err.printf ("Failed while reading bytes from %s: %s", url.toExternalForm(), e.getMessage());
  e.printStackTrace ();
  // Perform any other exception handling that's appropriate.
}
finally {
  if (is != null) { is.close(); }
}
return baos.toByteArray():

在 getTileUrl 中为 Maps Tile Android 添加授权 header

Adding an Authorization header in getTileUrl for Maps Tile Android

url

android

google-maps

http-headers