我想从数据库中检索折线路径，但是当我运行应用程序时，log cat总是说它是StringIndexOutOfbound。我看到解码折线过程中的错误。这是我的代码段：
private class RetriveTask extends AsyncTask<Void, Void, String>{
@Override
protected String doInBackground(Void... params) {
// TODO Auto-generated method stub
String strUrl = "http://my IP Adress/ta/1104505001/android/saved/retrieve.php";
URL url = null;
StringBuffer sb = new StringBuffer();
try{
url = new URL(strUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream iStream = connection.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(iStream));
String line="";
while((line=reader.readLine())!=null){
sb.append(line);
}
reader.close();
iStream.close();
}catch(MalformedURLException e){
e.printStackTrace();
}catch(IOException e){
e.printStackTrace();
}
return sb.toString();
}
protected void onPostExecute(String result){
super.onPostExecute(result);
new ParserTask().execute(result);
}
}
private class ParserTask extends AsyncTask<String, Void, List<HashMap<String,String>>>{
@Override
protected List<HashMap<String, String>> doInBackground(String... jsonData) {
// TODO Auto-generated method stub
PolylineJSONParser polyParser = new PolylineJSONParser();
JSONObject json=null;
try{
json = new JSONObject(jsonData[0]);
}catch(JSONException e){
e.printStackTrace();
}
List<HashMap<String,String>>routes = polyParser.parse(json);
return routes;
}
@Override
protected void onPostExecute(List<HashMap<String,String>>routes){
ArrayList<String> d = new ArrayList<String>();
List<LatLng> poly;
List<List<LatLng>> f = new ArrayList<List<LatLng>>();
for(int i=0;i<routes.size();i++){
String j = routes.get(i).get("path");
d.add(j);
}
for(int j=0;j<d.size();j++){
poly = new ArrayList<LatLng>();
String k = d.get(j);
poly = decodePoly(k);
f.add(poly);
Toast.makeText(MainActivity.this, "berhasil", Toast.LENGTH_SHORT).show();
}
/*ArrayList<LatLng> point1 = null;
PolylineOptions polyLineOptions = null;
for(int i = 0; i < routes.size(); i++){
point1=new ArrayList<LatLng>();
polyLineOptions = new PolylineOptions();
List<HashMap<String,String>> path = routes.get(i);
for(int a=0;a<path.size();a++){
HashMap<String,String> point = path.get(a);
double lat = Double.parseDouble(point.get("lat"));
double lng = Double.parseDouble(point.get("lng"));
LatLng posisi = new LatLng(lat,lng);
point1.add(posisi);
}
polyLineOptions.addAll(point1);
polyLineOptions.width(2);
polyLineOptions.color(Color.BLUE);
}
map.addPolyline(polyLineOptions);*/
}
}
private List<LatLng> decodePoly(String encoded) {
List<LatLng> poly = new ArrayList<LatLng>();
int index = 0, len = encoded.length();
int lat = 0, lng = 0;
while (index < len) {
int b, shift = 0, result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lat += dlat;
shift = 0;
result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lng += dlng;
LatLng p = new LatLng((((double) lat / 1E5)),
(((double) lng / 1E5)));
poly.add(p);
}
return poly;
}
这是JSONParser类
public class PolylineJSONParser {
public List<HashMap<String,String>> parse(JSONObject jObject){
JSONArray jMarkers = null;
try{
jMarkers = jObject.getJSONArray("polyline");
}catch(JSONException e){
e.printStackTrace();
}
return getMarkers(jMarkers);
}
private List<HashMap<String, String>> getMarkers(JSONArray jMarkers){
int markersCount = jMarkers.length();
List<HashMap<String,String>> markersList = new ArrayList<HashMap<String,String>>();
HashMap<String, String> marker = null;
for(int i=0; i<markersCount;i++){
try{
marker = getMarker((JSONObject)jMarkers.get(i));
markersList.add(marker);
}catch(JSONException e){
e.printStackTrace();
}
}
return markersList;
}
private HashMap<String,String> getMarker(JSONObject jMarker){
HashMap<String,String> marker = new HashMap<String,String>();
String path = "-NA-";
try{
if(!jMarker.isNull("path")){
path=jMarker.getString("path");
}
marker.put("path", path);
}catch(JSONException e){
e.printStackTrace();
}
return marker;
}
}
这是日志猫说的：
12-15 13:51:58.270: E/AndroidRuntime(26844): FATAL EXCEPTION: main
12-15 13:51:58.270: E/AndroidRuntime(26844): java.lang.StringIndexOutOfBoundsException: length=23; index=23
12-15 13:51:58.270: E/AndroidRuntime(26844): at com.evy.MainActivity.decodePoly(MainActivity.java:262)
12-15 13:51:58.270: E/AndroidRuntime(26844): at com.evy.MainActivity.access$0(MainActivity.java:243)
12-15 13:51:58.270: E/AndroidRuntime(26844): at com.evy.MainActivity$ParserTask.onPostExecute(MainActivity.java:215)
12-15 13:51:58.270: E/AndroidRuntime(26844): at com.evy.MainActivity$ParserTask.onPostExecute(MainActivity.java:1)
12-15 13:51:58.270: E/AndroidRuntime(26844): at android.os.AsyncTask.finish(AsyncTask.java:631)
12-15 13:51:58.270: E/AndroidRuntime(26844): at android.os.AsyncTask.access$600(AsyncTask.java:177)
12-15 13:51:58.270: E/AndroidRuntime(26844): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
12-15 13:51:58.270: E/AndroidRuntime(26844): at android.os.Handler.dispatchMessage(Handler.java:99)
12-15 13:51:58.270: E/AndroidRuntime(26844): at android.os.Looper.loop(Looper.java:176)
12-15 13:51:58.270: E/AndroidRuntime(26844): at android.app.ActivityThread.main(ActivityThread.java:5419)
12-15 13:51:58.270: E/AndroidRuntime(26844): at java.lang.reflect.Method.invokeNative(Native Method)
12-15 13:51:58.270: E/AndroidRuntime(26844): at java.lang.reflect.Method.invoke(Method.java:525)
12-15 13:51:58.270: E/AndroidRuntime(26844): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
12-15 13:51:58.270: E/AndroidRuntime(26844): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
12-15 13:51:58.270: E/AndroidRuntime(26844): at dalvik.system.NativeStart.main(Native Method)
我该怎么办？
答案 0 :(得分：0)
在你的while循环中尝试更改索引＆lt; len到索引＆lt; LEN + 1。 希望能解决String out of bound问题。