Android-Maps-Extensions InfoContents 生成异常

Question

在我的方法的一部分中，我将信息内容配置为从标记的 "title" 中获取 html 内容并将其显示在信息 window 中。我还使 window 成为可点击的 link。我正在使用 Android-Maps-Extensions 对标记进行聚类。

private void setUpMapIfNeeded() {
        // Do a null check to confirm that we have not already instantiated the map.
        if (mMap == null) {
            // Try to obtain the map from the SupportMapFragment.
            mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                    .getExtendedMap();
            // Check if we were successful in obtaining the map.
            if (mMap != null) {
                mMap.setInfoWindowAdapter(new GoogleMap.InfoWindowAdapter() {
                    @Override
                    public View getInfoWindow(Marker marker) {
                        return null;
                    }

                    @Override
                    public View getInfoContents(Marker marker) {
                        View v = getLayoutInflater().inflate(R.layout.infowindow_layout, null);
                        TextView textView = (TextView) v.findViewById(R.id.marker_label);
                        Spanned spannedContent = Html.fromHtml(marker.getTitle());
                        textView.setText(spannedContent, TextView.BufferType.SPANNABLE);
                        return v;
                    }
                });

                mMap.setOnInfoWindowClickListener(new GoogleMap.OnInfoWindowClickListener() {
                    @Override
                    public void onInfoWindowClick(Marker marker) {
                        int firstindex = marker.getTitle().indexOf("href=")+5;
                        int lastindex = marker.getTitle().indexOf("target='_blank'");
                        String s = marker.getTitle().substring(firstindex,lastindex);
                        Log.d("myapplication", s);
                        Uri uri = Uri.parse(s);
                        Intent intent = new Intent(Intent.ACTION_VIEW, uri);
                        startActivity(intent);

                    }
                });

                ClusteringSettings clusteringSettings = new ClusteringSettings();
                mMap.setClustering(clusteringSettings);

                setUpMap();
            }
        }
    }

当我按下单个标记时，它会显示信息window 就好了（就像我添加 ClusterSettings 和 setClustering 代码之前一样）。然而，当我按下一个集群时，我得到了这个异常：

01-08 15:00:20.210    3384-3384/com.example.ron.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.NullPointerException
            at java.io.StringReader.<init>(StringReader.java:46)
            at android.text.HtmlToSpannedConverter.convert(Html.java:411)
            at android.text.Html.fromHtml(Html.java:139)
            at android.text.Html.fromHtml(Html.java:102)
            at com.example.ron.myapplication.MapsActivity.getInfoContents(MapsActivity.java:81)
            at com.androidmapsextensions.impl.DelegatingGoogleMap$DelegatingInfoWindowAdapter.getInfoContents(DelegatingGoogleMap.java:414)
            at com.google.android.gms.maps.GoogleMap.g(Unknown Source)
            at com.google.android.gms.maps.internal.d$a.onTransact(Unknown Source)
            at android.os.Binder.transact(Binder.java:279)
            at com.google.android.gms.maps.internal.p.b(SourceFile:112)
            at com.google.maps.api.android.lib6.c.h.a(Unknown Source)
            at com.google.maps.api.android.lib6.c.h.a(Unknown Source)
            at com.google.maps.api.android.lib6.gmm6.c.h.b(Unknown Source)
            at com.google.maps.api.android.lib6.gmm6.c.j.c(Unknown Source)
            at com.google.maps.api.android.lib6.c.al.c(Unknown Source)
            at com.google.maps.api.android.lib6.c.aj.g(Unknown Source)
            at com.google.maps.api.android.lib6.c.al.h(Unknown Source)
            at com.google.maps.api.android.lib6.gmm6.c.h.a(Unknown Source)
            at com.google.maps.api.android.lib6.gmm6.o.aw.a(Unknown Source)
            at com.google.maps.api.android.lib6.gmm6.o.bf.a(Unknown Source)
            at com.google.maps.api.android.lib6.gmm6.o.be.a(Unknown Source)
            at com.google.maps.api.android.lib6.gmm6.o.bx.d(Unknown Source)
            at com.google.maps.api.android.lib6.gmm6.o.ak.onSingleTapConfirmed(Unknown Source)
            at com.google.maps.api.android.lib6.gmm6.i.g.onSingleTapConfirmed(Unknown Source)
            at com.google.maps.api.android.lib6.gmm6.i.i.handleMessage(Unknown Source)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:123)
            at android.app.ActivityThread.main(ActivityThread.java:3687)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:507)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
            at dalvik.system.NativeStart.main(Native Method)

似乎当我按下集群时，它会调用信息内容和信息window。无论如何，我可以禁用实际集群的信息window，并在按下集群时放大它吗？

如果您需要更多说明或需要更多信息，请在下方发表评论。

编辑：感谢 MaciejGórski 解决了问题。我将 getInfoContents 方法更改为此，这样我就不会收到错误：

public View getInfoContents(Marker marker) {
                    View v = getLayoutInflater().inflate(R.layout.infowindow_layout, null);
                    if (marker.isCluster()) {
                        return null;
                    }
                    TextView textView = (TextView) v.findViewById(R.id.marker_label);
                    Spanned spannedContent = Html.fromHtml(marker.getTitle());
                    textView.setText(spannedContent, TextView.BufferType.SPANNABLE);
                    return v;
                }
            });

Answer 1

簇标记默认没有标题。您收到 NPE，因为您将 null 发送到 Android 需要一些 non-null 值的代码。

您可能希望以不同的方式为它们生成标题，例如通过迭代集群中的所有标记：

if (marker.isCluster()) {
    Collection<Marker> markers = marker.getMarkers();
    // itarate over markers and getTitle on each
} else {
    // your old code
}

查看演示应用程序中的相关代码：DemoFragment.java。