我在尝试提取从JSON返回的数据并存储为Polyline对象时遇到了一些问题。 JSON格式如下：
{
"messages": [
],
"routes": {
"fieldAliases": {
"ObjectID": "ObjectID",
"Name": "Name",
"FirstStopID": "FirstStopID",
"LastStopID": "LastStopID",
"StopCount": "StopCount",
"Total_Meters": "Total_Meters",
"Shape_Length": "Shape_Length"
},
"geometryType": "esriGeometryPolyline",
"spatialReference": {
"wkid": 3414,
"latestWkid": 3414
},
"features": [
{
"attributes": {
"ObjectID": 1,
"Name": "18304.68,36152.73 - 21591.48,33095.24",
"FirstStopID": 1,
"LastStopID": 2,
"StopCount": 2,
"Total_Meters": 6757.9427813693819,
"Shape_Length": 6757.9404808662866
},
"geometry": {
"paths": [
[
[
18301.44000000041,
36146.919999999925
],
[
21206.919999999925,
33505.550000000745
],
[
21341.230000000447,
33566.929999999702
],
我得到返回的JSON并将每个点存储为Polyline对象的代码：
public void getDirection(Event eventModel){
String eventX = eventModel.getEventX();
Log.i("X", eventX);
String eventY = eventModel.getEventY();
Log.i("Y", eventY);
SimpleLineSymbol lineSymbol = new SimpleLineSymbol(
Color.GREEN, 3, SimpleLineSymbol.STYLE.DASH);
List pointArr = null;
String page;
JSONArray jsonArray;
try {
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet("http://www.onemap.sg/API/services.svc/route/solve?token=qo/s2TnSUmfLz+32CvLC4RMVkzEFYjxqyti1KhByvEacEdMWBpCuSSQ+IFRT84QjGPBCuz/cBom8PfSm3GjEsGc8PkdEEOEr&routeStops=18304.68,36152.73;" + eventX + "," + eventY + "&routemode=DRIVE&avoidERP=0&routeOption=shortes");
HttpResponse response = client.execute(request);
HttpEntity entity = response.getEntity();
String responseString = EntityUtils.toString(entity, "UTF-8");
page = "{\'EventDirection\':" + responseString + "}";
try {
JSONObject jsonObject = new JSONObject(page);
jsonArray = jsonObject.getJSONArray("EventDirection");
int length = jsonArray.length();
for (int i = 0; i < length; i++) {
JSONObject attribute = jsonArray.getJSONObject(i);
if(attribute.equals("features")){
if(attribute.equals("geometry")){
String path = attribute.getString("paths");
pointArr.add(path);
/*path = path.replace("[[\"", "");
path = path.replace("\"]]", "");
String[] arr = path.split(";");
for (int j = 0; j < arr.length; j++) {
String[] point = arr[j].split(",");
pointArr.add(point);
}*/
}}
}
Graphic lineGraphic = new Graphic((Geometry) pointArr, lineSymbol);
ENeighbourhoodActivity.graphicsLayer.addGraphic(lineGraphic);
} catch (JSONException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
}
我已经得到了堆栈跟踪：
11-24 20:32:19.425: D/dalvikvm(16607): GC_CONCURRENT freed 719K, 13% free 12030K/13703K, paused 7ms+13ms
11-24 20:32:19.628: W/System.err(16607): org.json.JSONException: Value {"directions":[{"features":[{"compressedGeometry":"+1+hrt+139j+0+0","attributes":{"length":0,"text":"Start at 18304.68,36152.73","time":0,"maneuverType":"esriDMTDepart","ETA":-2209161600000}},{"compressedGeometry":"+1+hrt+139j+172-lr+40-1i+1l-e+23-3+d+4+1d+r","attributes":{"length":1.7571306436022183,"text":"Go southeast on PAN ISLAND EXPRESSWAY","time":1.8785585885556129,"maneuverType":"esriDMTStraight","ETA":-2209161600000}},{"compressedGeometry":"+1+jch+12ik+i+1o+d+1v","attributes":{"length":0.12315161844398603,"text":"Bear left on TOH TUCK AVENUE","time":0.18480000000000038,"maneuverType":"esriDMTBearLeft","ETA":-2209161600000}},{"compressedGeometry":"+1+jdg+12mb+14-1+42+1b+p+m+11+2a+c+e+l+e+r+9+1q+2+o+5+1m+e+1v+o+3u+c+1u+0+1q-6+3a-i+11+2+1e+k+1k+12+1o+o+p+a+1p+a+m+8+m+b+2d+s+1g+t","attributes":{"length":1.3971933538812136,"text":"Turn right on TOH TUCK ROAD","time":2.7943955099999993,"maneuverType":"esriDMTTurnRight","ETA":-2209161600000}},{"compressedGeometry":"+1+kl9+132b+1l-1i+19-o+g-3+2e-8+3h-5+44-2+1i+4+1r+u+v+11+2v+43","attributes":{"length":0.78371010402386,"text":"Turn right on JALAN JURONG KECHIL","time":1.175752590000001,"maneuverType":"esriDMTTurnRight","ETA":-2209161600000}},{"compressedGeometry":"+1+la5+135l+1g-23+29-2o+1f-2d+d-1b+0-23-b-17-k-1n+0-h+8-l+o-r","attributes":{"length":0.5739351553531507,"text":"Turn right on JALAN ANAK BUKIT","time":0.9289808300000004,"maneuverType":"esriDMTTurnRight","ETA":-2209161600000}},{"compressedGeometry":"+1+lfr+12m0+dd-4m+qr-94+19n-ej+1j-n+82-56+gl-b4+5l-1a+3n-b+q-5+i-4+2k-13+4t-l+9p-14+co-3a+1r-j+1k-4+5o-1t+u-3+c+6+i+f+d+h","attributes":{"length":5.512234370362195,"text":"Bear left on DUNEARN ROAD","time":8.347599999999996,"maneuverType":"esriDMTBearLeft","ETA":-2209161600000}},{"compressedGeometry":"+1+qge+10ut+10+30+2p+5h","attributes":{"length":0.2995301962581563,"text":"Bear left on WHITLEY ROAD","time":0.4492,"maneuverType":"esriDMTBearLeft","ETA":-2209161600000}},{"compressedGeometry":"+1+qk7+117e+h-4+1p-1a+29-2o+j-b+q-2+b+4+h+c+c+h+10+2a+b+d+e+8+3n+3","attributes":{"length":0.5376352927205378,"text":"Turn right on MALCOLM ROAD","time":1.2903999999999978,"maneuverType":"esriDMTTurnRight","ETA":-2209161600000}},{"compressedGeometry":"+1+r0v+116u+f-k+l-a+t-1+s+7+1i+j+u+h+m+g+o+p+11+1f+11+u","attributes":{"length":0.35816860827144775,"text":"Turn right at UNNAMED ROAD to stay on MALCOLM ROAD","time":0.8596014644118043,"maneuverType":"esriDMTTurnRight","ETA":-2209161600000}},{"compressedGeometry":"+1+r9s+11b0+0+0","attributes":{"length":0,"text":"Finish at 27985.4,34115, on the right","time":0,"maneuverType":"esriDMTStop","ETA":-2209161600000}}],"summary":{"totalDriveTime":17.909288982967414,"totalTime":17.909288986120373,"envelope":{"ymin":33719.41002910024,"ymax":36152.73002910059,"xmin":18301.436076220416,"spatialReference":{"latestWkid":3414,"wkid":3414},"xmax":27985.400018159162},"totalLength":11.342689342916765},"routeName":"18304.68,36152.73 - 27985.4,34115","routeId":1}],"routes":{"features":[{"geometry":{"paths":[[[18301.44000000041,36146.919999999925],[18885.830000000075,35820.75999999978],[19550.639999999665,35448.38000000082],[19679.16000000015,35397.5700000003],[19731.700000000186,35383.86999999918],[19799.240000000224,35381.169999999925],[19812.37999999989,35385.49000000022],[19828.570000000298,35394.31000000052],[19856.860000000335,35412.300000000745],[19875.230000000447,35468.13000000082],[19885.419999999925,35519.13000000082],[19887.83999999985,35531.25999999978],[19924.03000000026,35530.199999999255],[20053.900000000373,35572.88000000082],[20071.599999999627,35586.460000000894],[20078.78000000026,35595.31000000052],[20088.94000000041,35614.65000000037],[20111.830000000075,35668.51999999955],[20124.389999999665,35682.72000000067],[20145.12999999989,35697.40000000037],[20171.889999999665,35706.49000000022],[20229.700000000186,35708.38000000082],[20254.44000000041,35712.52999999933],[20308.200000000186,35726.9299999997],[20361.94000000041,35748.6799999997],[20371.480000000447,35751.439
11-24 20:32:19.651: W/System.err(16607): at org.json.JSON.typeMismatch(JSON.java:100)
11-24 20:32:19.651: W/System.err(16607): at org.json.JSONObject.getJSONArray(JSONObject.java:548)
11-24 20:32:19.651: W/System.err(16607): at Controller.EventController.getDirection(EventController.java:222)
11-24 20:32:19.651: W/System.err(16607): at AsyncTask.GetEventDirectionAsyncTask.doInBackground(GetEventDirectionAsyncTask.java:21)
11-24 20:32:19.651: W/System.err(16607): at AsyncTask.GetEventDirectionAsyncTask.doInBackground(GetEventDirectionAsyncTask.java:1)
11-24 20:32:19.651: W/System.err(16607): at android.os.AsyncTask$2.call(AsyncTask.java:264)
11-24 20:32:19.651: W/System.err(16607): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
11-24 20:32:19.651: W/System.err(16607): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
11-24 20:32:19.651: W/System.err(16607): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208)
11-24 20:32:19.651: W/System.err(16607): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
11-24 20:32:19.651: W/System.err(16607): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
11-24 20:32:19.651: W/System.err(16607): at java.lang.Thread.run(Thread.java:856)
11-24 20:32:40.862: W/SurfaceView(16607): CHECK surface infomation creating=false formatChanged=false sizeChanged=false visible=false visibleChanged=true surfaceChanged=true realSizeChanged=false redrawNeeded=false left=false top=false
任何指南？提前谢谢。
修改
try {
JSONObject jsonObject = new JSONObject(page);
JSONObject myObject = jsonObject.getJSONObject("routes");
JSONArray features = myObject.getJSONArray("features");
JSONObject geometry = features.getJSONObject(1);
jsonArray = geometry.getJSONArray("paths");
int length = geometry.length();
for (int i = 0; i < length; i++) {
JSONObject attribute = jsonArray.getJSONObject(i);
String path = attribute.getString("paths");
path = path.replace("[[\"", "");
path = path.replace("\"]]", "");
String[] arr = path.split(";");
for (int j = 0; j < arr.length; j++) {
String[] point = arr[j].split(",");
pointArr.add(point);
}
}
答案 0 :(得分：0)
问题在于您获得的JSON是以下内容:(从堆栈跟踪中获取的摘录）：您可以看到数据结构与您的预期完全不同：
浏览的方法是了解哪个部分是JSONObject，哪个部分是JSONArray ......这很容易：看看我的评论
{ //<--------- global JSONObject
"directions" : [
{
"features" : [ //<---------it starts with [, so it's an array
{
"compressedGeometry" : "+1+hrt+139j+0+0",
"attributes" : {
"length" : 0,
"text" : "Start at 18304.68,36152.73",
"time" : 0,
"maneuverType" : "esriDMTDepart",
"ETA" : -2209161600000
}
},
... //a lot of items here
], //end of features
"summary" : { //<---------curly braces mean JSONObject !
"totalDriveTime" : 17.909288982967414,
"totalTime" : 17.909288986120373,
"envelope" : {
"ymin" : 33719.41002910024,
"ymax" : 36152.73002910059,
"xmin" : 18301.436076220416,
"spatialReference" : {
"latestWkid" : 3414,
"wkid" : 3414
},
"xmax" : 27985.400018159162
},
"totalLength" : 11.342689342916765
},
"routeName" : "18304.68,36152.73 - 27985.4,34115",
"routeId" : 1
}
], //<------- end of the array directions
"routes" : { //<---------curly braces mean routes is an JSONObject !
"features" : [{ // features is an array, which contains objects where its first attribute is a JSONObject named geometry
"geometry" : {
"paths" : [[[18301.44000000041, 36146.919999999925], [18885.830000000075, 35820.75999999978], [19550.639999999665, 35448.38000000082], [19679.16000000015, 35397.5700000003], [19731.700000000186, 35383.86999999918], [19799.240000000224, 35381.169999999925], [19812.37999999989, 35385.49000000022], [19828.570000000298, 35394.31000000052], [19856.860000000335, 35412.300000000745], [19875.230000000447, 35468.13000000082], [19885.419999999925, 35519.13000000082], [19887.83999999985, 35531.25999999978], [19924.03000000026, 35530.199999999255], [20053.900000000373, 35572.88000000082], [20071.599999999627, 35586.460000000894], [20078.78000000026, 35595.31000000052], [20088.94000000041, 35614.65000000037], [20111.830000000075, 35668.51999999955], [20124.389999999665, 35682.72000000067], [20145.12999999989, 35697.40000000037], [20171.889999999665, 35706.49000000022], [20229.700000000186, 35708.38000000082], [20254.44000000041, 35712.52999999933], [20308.200000000186, 35726.9299999997], [20361.94000000041, 35748.6799999997], [20371.480000000447, 35751.439
所以你有一个JSON对象，它具有以下属性：directions和routes，以及routes是另一个具有名为features的属性的对象，它是一个数组每个元素的第一个属性必须为geometry的元素，这是第一个属性为path的对象...除以你将获胜