Question

我正在尝试在我的Google地图活动中显示降水天气图层，但无法理解为什么它没有在地图上显示。我已在app\src\debug\res\values\google_maps_api.xml中实施了我的Google地图密钥，在Android SDK管理器中安装了Google Play服务，并且我已经为其API建立了一个OpenWeatherMap帐户（将在下面删除）。

地图加载正常，当我在单独的浏览器中使用输入的缩放搜索图层时，x，y显示正常，但我无法让图层显示在我的Google地图活动中。

我是否需要定义x，y，zoom或从URL中提取这些内容？

这是我的java：

package com.example.user.project;

import android.support.v4.app.FragmentActivity;
import android.os.Bundle;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.TileOverlay;
import com.google.android.gms.maps.model.TileOverlayOptions;
import com.google.android.gms.maps.model.TileProvider;
import com.google.android.gms.maps.model.UrlTileProvider;

import java.net.MalformedURLException;
import java.net.URL;
import java.util.Locale;

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    /**
     * Manipulates the map once available.
     * This callback is triggered when the map is ready to be used.
     * This is where we can add markers or lines, add listeners or move the camera. In this case,
     * we just add a marker near Sydney, Australia.
     * If Google Play services is not installed on the device, the user will be prompted to install
     * it inside the SupportMapFragment. This method will only be triggered once the user has
     * installed Google Play services and returned to the app.
     */
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        // Move the camera
        LatLng indy = new LatLng(39, -86.5);
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(indy, 8));

        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(Locale.US, "http://tile.openweathermap.org/map/precipitation/%d/%d/%d.png?appid={my_key}",
                        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;

                return !(zoom < minZoom || zoom > maxZoom);

            }
        };

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

以下是Android Studio生成的布局：

<fragment xmlns:android="http://schemas.android.com/apk/res/android"
          xmlns:map="http://schemas.android.com/apk/res-auto"
          xmlns:tools="http://schemas.android.com/tools"
          android:id="@+id/map"
          android:name="com.google.android.gms.maps.SupportMapFragment"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          tools:context="com.example.user.project.MapsActivity"/>

我已经按照OpenWeatherMap，Google Maps API和Android开发者提供的教程和文档进行了操作，但不明白为什么这样做不起作用。

我错过了什么？

Answer 1

您将等级8设置为地图的缩放级别，但您也可以将缩放级别限制在12到16之间，以便TileProvider可见。

删除它：

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

如果您不需要任何比例限制，您也可以删除checkTileExists方法。

如何正确获取天气瓷砖图层？

1 个答案: