我正在创建一个应用，该应用绘制了一条从用户当前位置到用户输入的目的地位置的路线。
使用Direction API时，我从API获取数据，但伴随错误“ org.json.JSONException：overview_polyLine无值”
private void getDirection() {
// currentPosition = new LatLng(mLastLocation.getLatitude(), mLastLocation.getLongitude());
if (mLastLocation != null) {
currentPosition = new LatLng (mLastLocation.getLatitude (), mLastLocation.getLongitude ());
}
String requestApi;
try {
requestApi = "https://maps.googleapis.com/maps/api/directions/json?" + "mode=driving&" + "transit_routing_preference=less_driving&" +
"origin=" + currentPosition.latitude + "," + currentPosition.longitude + "&" +
"destination=" + destination + "&" +
"key=" + getResources ().getString (R.string.google_direction_api);
Log.d ("Ashutosh", requestApi);
mService.getPath (requestApi)
.enqueue (new Callback<String> () {
@Override
public void onResponse(Call<String> call, Response<String> response) {
try {
JSONObject jsonObject = new JSONObject (response.body ().toString ());
JSONArray jsonArray = jsonObject.getJSONArray ("routes");
JSONObject route = jsonArray.getJSONObject (0);
JSONObject poly = route.getJSONObject ("overview_polyLine");
String polyline = poly.getString ("points");
polyLineList = decodePoly (polyline);
if (!polyLineList.isEmpty ()) {
LatLngBounds.Builder builder = new LatLngBounds.Builder ();
for (LatLng latLng : polyLineList) {
builder.include (latLng);
}
LatLngBounds bounds = builder.build ();
CameraUpdate mCameraUpdate = CameraUpdateFactory.newLatLngBounds (bounds, 2);
mMap.animateCamera (mCameraUpdate);
}
polylineOptions = new PolylineOptions ();
polylineOptions.color (Color.BLUE);
polylineOptions.width (5);
polylineOptions.startCap (new SquareCap ());
polylineOptions.endCap (new SquareCap ());
polylineOptions.jointType (JointType.ROUND);
polylineOptions.addAll (polyLineList);
greyPolyline = mMap.addPolyline (polylineOptions);
blackpolyLineOptions = new PolylineOptions ();
blackpolyLineOptions.color (Color.BLACK);
blackpolyLineOptions.width (5);
blackpolyLineOptions.startCap (new SquareCap ());
blackpolyLineOptions.endCap (new SquareCap ());
blackpolyLineOptions.jointType (JointType.ROUND);
blackPolyline = mMap.addPolyline (blackpolyLineOptions);
mMap.addMarker (new MarkerOptions ()
.position (polyLineList.get (polyLineList.size () - 1))
.title ("Pickup Location"));
//Animation
ValueAnimator polylineAnimator = ValueAnimator.ofInt (0, 100);
polylineAnimator.setDuration (2000);
polylineAnimator.setInterpolator (new LinearInterpolator ());
polylineAnimator.addUpdateListener (new ValueAnimator.AnimatorUpdateListener () {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
List<LatLng> points = greyPolyline.getPoints ();
int percentValue = (int) animation.getAnimatedValue ();
int size = points.size ();
int new_Points = (int) (size * (percentValue / 100.0f));
List<LatLng> p = points.subList (0, new_Points);
blackPolyline.setPoints (p);
}
});
polylineAnimator.start ();
carMarker = mMap.addMarker (new MarkerOptions ().position (currentPosition)
.flat (true)
.icon (BitmapDescriptorFactory.fromResource (R.drawable.car)));
handler = new Handler ();
index = -1;
next = 1;
handler.postDelayed (drawPathRunnable, 3000);
} catch (JSONException e) {
e.printStackTrace ();
}
}
@Override
public void onFailure(Call<String> call, Throwable t) {
Toast.makeText (MapsActivity.this, "" + t.getMessage (), Toast.LENGTH_SHORT).show ();
}
});
} catch (Exception e) {
e.printStackTrace ();
}
}
我从API获取数据，但由于此错误而无法在google地图上显示。
来自Logcat的错误。
2019-10-15 09:41:23.007 13728-13728/com.example.uber W/System.err: org.json.JSONException: No value for overview_polyLine
2019-10-15 09:41:23.007 13728-13728/com.example.uber W/System.err: at org.json.JSONObject.get(JSONObject.java:392)
2019-10-15 09:41:23.007 13728-13728/com.example.uber W/System.err: at org.json.JSONObject.getJSONObject(JSONObject.java:612)
2019-10-15 09:41:23.007 13728-13728/com.example.uber W/System.err: at com.example.uber.MapsActivity$4.onResponse(MapsActivity.java:299)
2019-10-15 09:41:23.008 13728-13728/com.example.uber W/System.err: at retrofit2.ExecutorCallAdapterFactory$ExecutorCallbackCall$1$1.run(ExecutorCallAdapterFactory.java:70)
2019-10-15 09:41:23.008 13728-13728/com.example.uber W/System.err: at android.os.Handler.handleCallback(Handler.java:808)
2019-10-15 09:41:23.008 13728-13728/com.example.uber W/System.err: at android.os.Handler.dispatchMessage(Handler.java:101)
2019-10-15 09:41:23.008 13728-13728/com.example.uber W/System.err: at android.os.Looper.loop(Looper.java:166)
2019-10-15 09:41:23.008 13728-13728/com.example.uber W/System.err: at android.app.ActivityThread.main(ActivityThread.java:7425)
2019-10-15 09:41:23.008 13728-13728/com.example.uber W/System.err: at java.lang.reflect.Method.invoke(Native Method)
2019-10-15 09:41:23.008 13728-13728/com.example.uber W/System.err: at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:245)
2019-10-15 09:41:23.008 13728-13728/com.example.uber W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:921)
我是android studio的新手。对错误原因的解释将帮助我将来防止错误发生。在此先感谢！
键区分大小写。实际密钥名称为overview_polyline，但不是overview_polyLine
似乎您的route JSONObject没有名为overview_polyLine的任何键。
为了防止异常，您需要检查天气密钥是否存在于JSON中。
您可以这样检查：
jsonObjectName。有（“ KeyName”）
JSONObject jsonObject = new JSONObject (response.body ().toString ());
if(jsonObject.has("routes")){
JSONArray jsonArray = jsonObject.getJSONArray ("routes");
JSONObject route = jsonArray.getJSONObject (0);
if(route.has("overview_polyLine")){
JSONObject poly = route.getJSONObject ("overview_polyLine");
}
}