你得到 android.os.NetworkOnMainThreadException ：

例外，当应用程序试图在其主线程进行网络操作时所引发。

这是只抛出针对蜂窝SDK或更高版本的应用程序。针对早期SDK版本的应用程序可以做网络上的主要事件循环线程，但它严重阻碍。

做你的code 这样侧的AsyncTask

I have problem with testing my application on device.
I already successfully open the localhost in browser from my device, but when i enter my ip to connect my application with web service it didn't work.
I always get the "unfortunately, [my apps name] has stopped" message.
Anyone who knows about this problem, please help me. I really need help to solve this. thank you very much

logcat - i get it from usb debug on device

06-10 11:31:15.551: D/dalvikvm(14590): Late-enabling CheckJNI
06-10 11:31:15.809: D/TextLayoutCache(14590): Using debug level: 0 - Debug Enabled: 0
06-10 11:31:15.902: D/libEGL(14590): loaded /vendor/lib/egl/libEGL_POWERVR_SGX540_120.so
06-10 11:31:15.910: D/libEGL(14590): loaded /vendor/lib/egl/libGLESv1_CM_POWERVR_SGX540_120.so
06-10 11:31:15.910: D/libEGL(14590): loaded /vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so
06-10 11:31:16.160: D/OpenGLRenderer(14590): Enabling debug mode 0
06-10 11:31:19.770: D/OpenGLRenderer(14590): Flushing caches (mode 0)
06-10 11:31:22.309: D/OpenGLRenderer(14590): Flushing caches (mode 0)
06-10 11:31:30.848: D/TryLoginCheck(14590): Here
06-10 11:31:30.848: I/System.out(14590): UserNametes
06-10 11:31:30.848: I/System.out(14590): passwordTes12345*
06-10 11:31:30.848: D/Parameters(14590): username=tes&password=Tes12345*
06-10 11:31:30.863: D/AndroidRuntime(14590): Shutting down VM
06-10 11:31:30.863: W/dalvikvm(14590): threadid=1: thread exiting with uncaught exception (group=0x40bd31f8)
06-10 11:31:30.863: E/AndroidRuntime(14590): FATAL EXCEPTION: main
06-10 11:31:30.863: E/AndroidRuntime(14590): android.os.NetworkOnMainThreadException
06-10 11:31:30.863: E/AndroidRuntime(14590):    at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.io.IoBridge.connect(IoBridge.java:112)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at java.net.Socket.connect(Socket.java:842)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.net.http.HttpConnection.<init>(HttpConnection.java:77)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:351)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:86)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:308)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.net.http.HttpEngine.connect(HttpEngine.java:303)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:282)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:232)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.net.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:80)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at libcore.net.http.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:188)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at com.karismaelearning.Login.tryLogin(Login.java:128)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at com.karismaelearning.Login$3.onClick(Login.java:73)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at android.view.View.performClick(View.java:3558)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at android.view.View$PerformClick.run(View.java:14157)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at android.os.Handler.handleCallback(Handler.java:605)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at android.os.Handler.dispatchMessage(Handler.java:92)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at android.os.Looper.loop(Looper.java:137)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at android.app.ActivityThread.main(ActivityThread.java:4514)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at java.lang.reflect.Method.invokeNative(Native Method)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at java.lang.reflect.Method.invoke(Method.java:511)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
06-10 11:31:30.863: E/AndroidRuntime(14590):    at dalvik.system.NativeStart.main(Native Method)
06-10 11:31:30.918: D/dalvikvm(14590): GC_CONCURRENT freed 237K, 6% free 6863K/7239K, paused 2ms+2ms

you are getting android.os.NetworkOnMainThreadException :

The exception that is thrown when an application attempts to perform a networking operation on its main thread.

This is only thrown for applications targeting the Honeycomb SDK or higher. Applications targeting earlier SDK versions are allowed to do networking on their main event loop threads, but it's heavily discouraged.

do your code this way in side AsyncTask