I am completely new to android programming and java programming. I have a existing web app which has coordinates stored in mysql database. By following some online tutorials on Google Map API and JSON i have written codes in order to display map markers for the points stored the database.
My php script returns the following output when run
[{"RowID":"15","LatLng":"(27.70171145916157, 85.30419380111698)","Type":"hospital"},{"RowID":"16","LatLng":"(27.704200193429045, 85.32494337005619)","Type":"hospital"}]
I have crated a class to parse the JSON data
public class ImportMarkers {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public ImportMarkers() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
and finally to display the markers in the map view that i have created i have used the following code
//url to make request
private static String url = "http://10.0.2.2/jsonsenddata.php";
//JSON Node names
private static final String id = "RowID";
private static final String latlng = "LatLng";
private static final String type = "Type";
JSONArray markers = null;
// Creating JSON Parser instance
ImportMarkers marker = new ImportMarkers();
// getting JSON string from URL
JSONObject json = marker.getJSONFromUrl(url);
try {
// Getting AJSONObjectrray
markers = json.getJSONArray(null);
// looping through All rows
for(int i = 0; i < markers.length(); i++){
JSONObject c = markers.getJSONObject(i);
// Storing each json item in variable
String RowID = c.getString(id);
String LatLng = c.getString(latlng);
String Type = c.getString(type);
String[] parts = LatLng.split(",");
String lat = parts[0];
String lon = parts[1];
float latInt = Float.valueOf(lat).floatValue();
float longInt = Float.valueOf(lon).floatValue();
GeoPoint X = new GeoPoint((int) (latInt*1E6),(int) (longInt*1E6) );
if (Type == "hospital"){
OverlayItem overlayItem = new OverlayItem (X , "Hospital", "ADDITION");
AddLocation hospital = new AddLocation (hos, MainActivity.this);
hospital.addLocation(overlayItem);
overlayList.add(hospital);
}
else {
OverlayItem overlayItem = new OverlayItem (X , "Airport", "ADDITION");
AddLocation airport = new AddLocation (air, MainActivity.this);
airport.addLocation(overlayItem);
overlayList.add(airport);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
I dont know what is wrong with my code , i would be greatful if anybody provided some help.
Here is my logcat log
12-02 13:45:41.348: D/dalvikvm(448): GC_CONCURRENT freed 174K, 4% free 6623K/6855K, paused 6ms+4ms
12-02 13:45:41.628: D/dalvikvm(448): GC_CONCURRENT freed 356K, 6% free 6823K/7239K, paused 4ms+4ms
12-02 13:45:42.028: D/dalvikvm(448): GC_CONCURRENT freed 699K, 11% free 6616K/7431K, paused 4ms+5ms
12-02 13:45:42.028: W/CursorWrapperInner(448): Cursor finalized without prior close()
12-02 13:45:42.038: W/CursorWrapperInner(448): Cursor finalized without prior close()
12-02 13:45:42.438: D/dalvikvm(448): GC_CONCURRENT freed 198K, 7% free 6929K/7431K, paused 4ms+7ms
12-02 13:45:42.789: D/dalvikvm(448): GC_CONCURRENT freed 311K, 5% free 7189K/7559K, paused 8ms+16ms
12-02 13:45:43.258: D/dalvikvm(448): GC_CONCURRENT freed 519K, 8% free 7234K/7815K, paused 5ms+7ms
12-02 13:45:43.580: D/dalvikvm(448): GC_CONCURRENT freed 267K, 6% free 7385K/7815K, paused 5ms+4ms
12-02 13:45:44.048: D/dalvikvm(448): GC_CONCURRENT freed 675K, 10% free 7259K/8007K, paused 5ms+4ms
12-02 13:45:44.148: D/AndroidRuntime(448): Shutting down VM
12-02 13:45:44.148: W/dalvikvm(448): threadid=1: thread exiting with uncaught exception (group=0x40014760)
12-02 13:45:44.168: E/AndroidRuntime(448): FATAL EXCEPTION: main
12-02 13:45:44.168: E/AndroidRuntime(448): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.finalyear.quakereact/com.finalyear.quakereact.MainActivity}: android.os.NetworkOnMainThreadException
12-02 13:45:44.168: E/AndroidRuntime(448): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1815)
12-02 13:45:44.168: E/AndroidRuntime(448): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1831)
12-02 13:45:44.168: E/AndroidRuntime(448): at android.app.ActivityThread.access$500(ActivityThread.java:122)
12-02 13:45:44.168: E/AndroidRuntime(448): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1024)
12-02 13:45:44.168: E/AndroidRuntime(448): at android.os.Handler.dispatchMessage(Handler.java:99)
12-02 13:45:44.168: E/AndroidRuntime(448): at android.os.Looper.loop(Looper.java:132)
12-02 13:45:44.168: E/AndroidRuntime(448): at android.app.ActivityThread.main(ActivityThread.java:4123)
12-02 13:45:44.168: E/AndroidRuntime(448): at java.lang.reflect.Method.invokeNative(Native Method)
12-02 13:45:44.168: E/AndroidRuntime(448): at java.lang.reflect.Method.invoke(Method.java:491)
12-02 13:45:44.168: E/AndroidRuntime(448): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
12-02 13:45:44.168: E/AndroidRuntime(448): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
12-02 13:45:44.168: E/AndroidRuntime(448): at dalvik.system.NativeStart.main(Native Method)
12-02 13:45:44.168: E/AndroidRuntime(448): Caused by: android.os.NetworkOnMainThreadException
12-02 13:45:44.168: E/AndroidRuntime(448): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1077)
12-02 13:45:44.168: E/AndroidRuntime(448): at dalvik.system.BlockGuard$WrappedNetworkSystem.connect(BlockGuard.java:368)
12-02 13:45:44.168: E/AndroidRuntime(448): at org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:208)
12-02 13:45:44.168: E/AndroidRuntime(448): at org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:431)
12-02 13:45:44.168: E/AndroidRuntime(448): at java.net.Socket.connect(Socket.java:901)
12-02 13:45:44.168: E/AndroidRuntime(448): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
12-02 13:45:44.168: E/AndroidRuntime(448): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:143)
12-02 13:45:44.168: E/AndroidRuntime(448): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
12-02 13:45:44.168: E/AndroidRuntime(448): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
12-02 13:45:44.168: E/AndroidRuntime(448): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
12-02 13:45:44.168: E/AndroidRuntime(448): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
12-02 13:45:44.168: E/AndroidRuntime(448): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
12-02 13:45:44.168: E/AndroidRuntime(448): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
12-02 13:45:44.168: E/AndroidRuntime(448): at com.finalyear.quakereact.ImportMarkers.getJSONFromUrl(ImportMarkers.java:38)
12-02 13:45:44.168: E/AndroidRuntime(448): at com.finalyear.quakereact.MainActivity.onCreate(MainActivity.java:80)
12-02 13:45:44.168: E/AndroidRuntime(448): at android.app.Activity.performCreate(Activity.java:4397)
12-02 13:45:44.168: E/AndroidRuntime(448): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1048)
12-02 13:45:44.168: E/AndroidRuntime(448): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1779)
12-02 13:45:44.168: E/AndroidRuntime(448): ... 11 more
12-02 13:46:42.368: I/Process(448): Sending signal. PID: 448 SIG: 9
Thank you in advance.
The exception is NetworkOnMainThreadException
So, fetch on a separate thread.
AsyncTaskperhaps? (if you need to update the UI)