java.lang.NullPointerException error in Android

Question

I am new to android, i am trying to retrieve data from mysql database to android text field.when i add the below line to my java file

JSONObject json = jsonParser.makeHttpRequest(
                url_product_detials, "GET", params);

it shows the error. if i remove the above (jsonParser.makeHttpRequest) line it works fine. the error i got in log files are,

01-02 11:16:50.418: W/System.err(968):  ... 17 more
01-02 11:16:50.418: E/Buffer Error(968): Error converting result java.lang.NullPointerException
01-02 11:16:50.418: E/JSON Parser(968): Error parsing data org.json.JSONException: End of input at character 0 of 
01-02 11:16:50.428: D/AndroidRuntime(968): Shutting down VM
01-02 11:16:50.428: W/dalvikvm(968): threadid=1: thread exiting with uncaught exception (group=0x40015560)
01-02 11:16:50.428: E/AndroidRuntime(968): FATAL EXCEPTION: main
01-02 11:16:50.428: E/AndroidRuntime(968): java.lang.NullPointerException
01-02 11:16:50.428: E/AndroidRuntime(968):  at com.example.matrixarc.Syl$GetProductDetails$1.run(Syl.java:153)
01-02 11:16:50.428: E/AndroidRuntime(968):  at android.os.Handler.handleCallback(Handler.java:587)
01-02 11:16:50.428: E/AndroidRuntime(968):  at android.os.Handler.dispatchMessage(Handler.java:92)
01-02 11:16:50.428: E/AndroidRuntime(968):  at android.os.Looper.loop(Looper.java:130)
01-02 11:16:50.428: E/AndroidRuntime(968):  at android.app.ActivityThread.main(ActivityThread.java:3683)
01-02 11:16:50.428: E/AndroidRuntime(968):  at java.lang.reflect.Method.invokeNative(Native Method)
01-02 11:16:50.428: E/AndroidRuntime(968):  at java.lang.reflect.Method.invoke(Method.java:507)
01-02 11:16:50.428: E/AndroidRuntime(968):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
01-02 11:16:50.428: E/AndroidRuntime(968):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
01-02 11:16:50.428: E/AndroidRuntime(968):  at dalvik.system.NativeStart.main(Native Method)
01-02 11:16:52.808: I/Process(968): Sending signal. PID: 968 SIG: 9

I have initialized url_product_detials as

private static final String url_product_detials = "http://localhost/connection/ggg.php";

It's telling you that nothing is being returned from that URL — Brian Roach
– Brian Roach, Commented Jan 2, 2014 at 6:01

Sabin Jose · Accepted Answer · 2014-01-02 06:15:39Z

1

In android localhost stands for the device/emulator . If you want to connect to your computer/local machine use IP 10.0.2.2

Change private static final String url_product_detials = "http://localhost/connection/ggg.php";

to private static final String url_product_detials = "http://10.0.2.2/connection/ggg.php";

edited Jan 2, 2014 at 6:15

answered Jan 2, 2014 at 6:08

Sabin Jose

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1 Comment

Loïc Faure-Lacroix Over a year ago

I'd recommend to use the host as a preference variable. If you ever want to install the app on a phone, the 10.0.2.2 or localhost won't work. Using a preference to change the hostname of the server should be the prefered way to do it.

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