android Webview App在启动时崩溃

构建一个通过webview访问页面的应用程序 . 但它在开始时崩溃，给出了以下运行时错误..

E / AndroidRuntime：致命异常：主要过程：com.aaryansoftwares.moopl.moopl，PID：2371了java.lang.RuntimeException：无法启动活动ComponentInfo {com.aaryansoftwares.moopl.moopl / com.aaryansoftwares.moopl.moopl.MainActivity }：android.os.NetworkOnMainThreadException在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2646）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2707）在android.app.ActivityThread.-wrap12（ActivityThread.java ）android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1460）在android.os.Handler.dispatchMessage（Handler.java:102）在android.os.Looper.loop（Looper.java:154）在android .app.ActivityThread.main（ActivityThread.java:6077）at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:865）at com的java.lang.reflect.Method.invoke（Native Method） .android.internal.os.ZygoteInit.main（ZygoteInit.java:755）引起：android.os.StrictMode $ And的android.os.NetworkOnMainThreadException roidBlockGuardPolicy.onNetwork（StrictMode.java:1303）在java.net.Inet6AddressImpl.lookupHostByName（Inet6AddressImpl.java:86）在java.net.Inet6AddressImpl.lookupAllHostAddr（Inet6AddressImpl.java:74）在java.net.InetAddress.getByName（InetAddress的的.java：708）在com.aaryansoftwares.moopl.moopl.MainActivity.isNetworkConnected（MainActivity.java:41）在com.aaryansoftwares.moopl.moopl.MainActivity.onCreate（MainActivity.java:20）在android.app.Activity . performCreate（Activity.java:6662）在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1118）在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2599）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java ：2707）在Android.app.Handler.dispatchMessage（Handler.java:102）的android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1460）的android.app.ActivityThread.-wrap12（ActivityThread.java）处android.app.Looper.loop（Looper.java:154）在android.app.ActivityThread.main（ActivityThread.java:6 077）位于com.android.internal.os.ZygoteInit.main的com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:865）的java.lang.reflect.Method.invoke（Native Method）（ ZygoteInit.java:755）申请已终止 .

主要活动：

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    if(isNetworkConnected()==true)
    {
        WebView start = (WebView) findViewById(R.id.activity_main);
        start.loadUrl("url here");
    }

    else
    {
        Intent i= new Intent(this,activityFail.class);
        startActivity(i);
    }

}

private boolean isNetworkConnected() {
    /*ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

    return cm.getActiveNetworkInfo() != null;*/


    try {
        final InetAddress address = InetAddress.getByName("www.google.com");
        return !address.equals("");
    } catch (UnknownHostException e) {
        // Log error
    }
    return false;
}

}

activityfail：

public class activityFail extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.connection_fail);

    ImageView img =(ImageView) findViewById(R.id.imageView);
    img.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent j=new Intent(getApplicationContext(), MainActivity.class);

        }
    });

}

}

清单：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.aaryansoftwares.moopl.moopl">
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>