来自URL的Android google mapv2图标

Question

现在出现了我无法从URL获取并在Google地图中显示自定义图标的问题.关于Google的示例,只有图标才会显示在Google地图中.但我想知道的是从URL显示图标.

private Marker melbourne = mMap.addMarker(new MarkerOptions()
                            .position(MELBOURNE)
                            .title("Melbourne")
                            .snippet("Population: 4,137,400")
                            .icon(BitmapDescriptorFactory.fromResource(R.drawable.arrow)));

这是我的编码.

            if(c != null){          
                if(c.moveToFirst()){
                    do {
                        googleMap.addMarker(new MarkerOptions()
                        .position(new LatLng(Double.parseDouble(c.getString(2)), Double.parseDouble(c.getString(3))))
                        .title(c.getString(0))
                        .icon(BitmapDescriptorFactory.fromBitmap(bmp))
                        .snippet(c.getString(1)));
                    } while(c.moveToNext());
                }               
            }

Answer 1

你可以下载Bitmap as

Bitmap bmp = BitmapFactory.decodeStream(myurl.openConnection().getInputStream());

使用线程来获取位图

然后

 .icon(BitmapDescriptorFactory.fromBitmap(bmp)));

从你的评论中得到 NetworkOnMainThreadException

所以使用一个线程.

Thread thread = new Thread(new Runnable(){
@Override
public void run(){
    URL url ;
    try {
        url = new URL("myurl");
        bmp = BitmapFactory.decodeStream(url.openConnection().getInputStream());
    } catch (Exception e) {
        e.printStackTrace();
    }
    runOnUiThread(new Runnable() {
        @Override
        public void run() {
            source = mMap.addMarker(new MarkerOptions()
                    .position(sc)
                    .title("MyHome")
                    .snippet("Bangalore")
                    .icon(BitmapDescriptorFactory.fromResource(bmp)));
        }
    });
}
});
thread.start();

您无法从后台线程更新ui.用runOnUiThread.

使用asycntask

让你的asycn成为你活动的内在阶级.将Bitmap声明为类变量.

 class TheTask extends AsyncTask <Void,Void,Void>
 {
@Override
protected void onPreExecute() {
    // TODO Auto-generated method stub
    super.onPreExecute();

}
@Override
protected Void doInBackground(Void... params) {
    URL url ;
    try {
    url = new URL("myurl");
    bmp = BitmapFactory.decodeStream(url.openConnection().getInputStream());
    } catch (Exception e) {
      e.printStackTrace();
         }
    return null;
}
@Override
protected void onPostExecute(Void result) {

super.onPostExecute(result);
    source = mMap.addMarker(new MarkerOptions()
    .position(sc)
    .title("MyHome")
    .snippet("Bangalore")                                                                                     
    .icon(BitmapDescriptorFactory.fromResource(R.drawable.pin)));                                       
    }
}

Answer 2

我用Ion来加载图像.这是一个非常好的图书馆.

从url设置标记图标非常简单.

try {
        Bitmap bmImg = Ion.with(context)
                .load("http://example.com").asBitmap().get();

        mMap.addMarker(new MarkerOptions().position(latlng)
                .icon(BitmapDescriptorFactory.fromBitmap(bmImg)));

    } catch (InterruptedException e) {
        e.printStackTrace();
    } catch (ExecutionException e) {
        e.printStackTrace();
    }

希望这个帮助