How to read the data from JSONArray in android?

Question

I have a following jsonarray and i want to parse it but i am getting null pointer exception.The url works in browser and the data is as below

{"showDriver":
               [{"IDDriver":"1","Driverlogtit":"24.614095","Driverlatite":"46.509689"},
                 {"IDDriver":"2","Driverlogtit":"24.639199","Driverlatite":"46.557047"},
                   {"IDDriver":"3","Driverlogtit":"24.651724","Driverlatite":"46.559131"},
                    {"IDDriver":"4","Driverlogtit":"24.625951","Driverlatite":"46.569466"},
                     {"IDDriver":"8","Driverlogtit":"24.626692","Driverlatite":"46.544095"}]}

in android when call json get me error

java.lang.NullPointerException
at com.project.ytubasi.speedtaxi.MapsActivity.WhereDriver(MapsActivity.java:329)
at com.project.ytubasi.speedtaxi.MapsActivity$3.onCameraIdle(MapsActivity.java:166)
at com.google.android.gms.maps.GoogleMap$22.onCameraIdle(Unknown Source)
at com.google.android.gms.maps.internal.zzf$zza.onTransact(Unknown Source)
at android.os.Binder.transact(Binder.java:361)
at ys.a(:com.google.android.gms.DynamiteModulesB:79)
at maps.ad.j.b(Unknown Source)
at maps.ad.j.a(Unknown Source)
at maps.ad.j$2.run(Unknown Source)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5293)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:855)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:671)
at dalvik.system.NativeStart.main(Native Method)

there any wrong in my class

here make call

  mGoogleMap.setOnCameraIdleListener(new GoogleMap.OnCameraIdleListener() {
        @Override
        public void onCameraIdle() {


            CameraLat = googleMap.getCameraPosition().target.latitude;
            CameraLong = googleMap.getCameraPosition().target.longitude;


            markerlocationtext.setText(getCompleteAddressString(CameraLat, CameraLong));


                WhereDriver(String.valueOf(CameraLong), String.valueOf(CameraLat));

                String lat = DriverList.get(0).Driverlatite;
                Toast.makeText(getApplicationContext(),""+lat,Toast.LENGTH_LONG).show();



        }
    });


}

my data class

 AQuery aq;
public void WhereDriver(String longt ,String lati) {


    String url=muUrl+"WhereDriver?logt=24.632652&lat=46.558625";//+longt+"&lat="+lati; i used stable Number to see data
    aq.ajax(url, JSONObject.class, this, "jsonCallback");
}


public void  jsonCallback(String url, JSONObject json, AjaxStatus status) throws JSONException {

    if(json != null){

        try {
            JSONArray DriverArray = json.getJSONArray("showDriver");

            for (int z = 0; z < DriverArray.length(); z++) {

                JSONObject jsDriverArray = DriverArray.getJSONObject(z);
                DriverList.add(new AllDriverLocation(jsDriverArray.getString("IDDriver"),
                        jsDriverArray.getString("Driverlogtit"),
                        jsDriverArray.getString("Driverlatite")));
            }
        }catch (Exception ex)
        {

        }



    }else{
    }

}

i define my list as

public ArrayList <AllDriverLocation>  DriverList = new ArrayList<>();

and AllDriverLocation class

public class AllDriverLocation {
String  IDDriver;
String  Driverlogtit;
String  Driverlatite;


public AllDriverLocation(String IDDriver, String driverlogtit, String driverlatite) {
    this.IDDriver = IDDriver;
    Driverlogtit = driverlogtit;
    Driverlatite = driverlatite;
}
}

Possible duplicate of [What is a NullPointerException, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) — Harshad Pansuriya, Nov 30 '16 at 08:59
this = {MapsActivity@830036345184} logt=24.632652&lat=46.558625" value = {char[94]@830044431056} hashCode = 1909014898 offset = 0 count = 94 aqu = null — Yasser Admi, Nov 30 '16 at 10:15

score 0 · Answer 1 · answered Nov 30 '16 at 09:11

0

The issue seems to be at this line -

WhereDriver(String.valueOf(CameraLong), String.valueOf(CameraLat));

Please check if the variables CameraLong and CameraLat are not null

answered Nov 30 '16 at 09:11

Darshan Pania

31
6

score 0 · Answer 2 · answered Nov 30 '16 at 09:28

try this:

JSONArray driverArray = response.getJSONArray("showDriver");
                    String IDDriver = "",Driverlogtit="",Driverlogtit="";
                    for (int z = 0; z < driverArray.length(); z++) {
                        try {
                            JSONObject jsDriverArray = driverArray.getJSONObject(z);
                            if(jsDriverArray.has("IDDriver")){
                                IDDriver = jsDriverArray.getString("IDDriver");
                            } if(jsDriverArray.has("Driverlogtit")){
                                Driverlogtit = jsDriverArray.getString("Driverlogtit");
                            } if(jsDriverArray.has("Driverlatite")){
                                Driverlogtit = jsDriverArray.getString("Driverlatite");
                            }

                            DriverList.add(new AllDriverLocation(IDDriver,Driverlogtit,Driverlogtit));
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }

JSONObject class has a method named "has":

http://developer.android.com/reference/org/json/JSONObject.html#has(java.lang.String)

Returns true if this object has a mapping for name. The mapping may be NULL.

You have check the "jsonCallback" json and print the "json". — Manikandan K, Nov 30 '16 at 10:35

score 0 · Answer 3 · answered Nov 30 '16 at 09:38

0

To Avoid app crash you can add condition which will check if driver array is null or not? Try this

JSONArray DriverArray = !data.isNull(getString("showDriver"))?data.getJSONArray(getString("showDriver")) : new JSONArray();

answered Nov 30 '16 at 09:38

Ashish Patel

3
2

instead of this you can go for optString() – Rushi Ayyappa Nov 30 '16 at 12:41

How to read the data from JSONArray in android?

3 Answers3