android OkHttpClient Requesting Error
<p>I am trying to store some data in mysql database using my android app. I am using okhttp3 to send request , but an error appears to me at this line:</p>

<pre><code>client.newCall(request).execute();
</code></pre>

<p>I tried it on local machine and online but it gives me the same error here is the code ,</p>

<pre><code>public class MainActivity extends AppCompatActivity {

    String token1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        System.out.println("MainActivity is :" + FirebaseInstanceId.getInstance().getToken());
        FirebaseMessaging.getInstance().subscribeToTopic("test");
        FirebaseInstanceId.getInstance().getToken();
        token1=FirebaseInstanceId.getInstance().getToken();
    }

    public void clicking(View view) {

        OkHttpClient client = new OkHttpClient();
        RequestBody body = new FormBody.Builder()
                .add("Token",token1)
                .build();

        okhttp3.Request request = new okhttp3.Request.Builder()
                .url("http://saleh923.byethost8.com/hii.html")
                .post(body)
                .build();

        try {
            client.newCall(request).execute();
        } catch (IOException e) {

            e.printStackTrace();
        }
    }
}
</code></pre>

<p>and here is the log:</p>

<pre><code> com.example.user.firebasenot E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.user.firebasenot, PID: 3280
    java.lang.IllegalStateException: Could not execute method for android:onClick
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
        at android.view.View.performClick(View.java:5198)
        at android.view.View$PerformClick.run(View.java:21147)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:148)
        at android.app.ActivityThread.main(ActivityThread.java:5417)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Method.invoke(Native Method)
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
        at android.view.View.performClick(View.java:5198) 
        at android.view.View$PerformClick.run(View.java:21147) 
        at android.os.Handler.handleCallback(Handler.java:739) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:148) 
        at android.app.ActivityThread.main(ActivityThread.java:5417) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
     Caused by: android.os.NetworkOnMainThreadException
        at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1273)
        at java.net.InetAddress.lookupHostByName(InetAddress.java:431)
        at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
        at java.net.InetAddress.getAllByName(InetAddress.java:215)
        at okhttp3.Dns$1.lookup(Dns.java:39)
        at okhttp3.internal.connection.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:172)
        at okhttp3.internal.connection.RouteSelector.nextProxy(RouteSelector.java:138)
        at okhttp3.internal.connection.RouteSelector.next(RouteSelector.java:80)
        at okhttp3.internal.connection.StreamAllocation.findConnection(StreamAllocation.java:178)
        at okhttp3.internal.connection.StreamAllocation.findHealthyConnection(StreamAllocation.java:129)
        at okhttp3.internal.connection.StreamAllocation.newStream(StreamAllocation.java:98)
        at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.java:42)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
        at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.java:109)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
        at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.java:93)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.java:124)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
        at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:170)
        at okhttp3.RealCall.execute(RealCall.java:60)
        at com.example.user.firebasenot.MainActivity.clicking(MainActivity.java:54)
        at java.lang.reflect.Method.invoke(Native Method) 
        at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
        at android.view.View.performClick(View.java:5198) 
        at android.view.View$PerformClick.run(View.java:21147) 
        at android.os.Handler.handleCallback(Handler.java:739) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:148) 
        at android.app.ActivityThread.main(ActivityThread.java:5417) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
</code></pre>