Android Studio Webview with Custom CSS (jsoup)

Question

I want to load facebook.com in a webview with custom CSS to change a few things. I use jsoup but everytime i start the app it crashes.

Here is my code:

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

    try {
        Document doc = Jsoup.connect("https://www.facebook.com").get();
        doc.head().getElementsByTag("link").remove();
        doc.head().appendElement("link").attr("rel", "stylesheet").attr("type", "text/css").attr("href", "style.css");
        String htmlData = doc.outerHtml();
        WebView webview = new WebView(this);
        setContentView(webview);
        webview.loadDataWithBaseURL("file:///android_asset/.", htmlData, "text/html", "UTF-8", null);

    } catch (IOException e) {
        e.printStackTrace();
    }
}

Logcat output

FATAL EXCEPTION: main Process: com.example.name.firstapp, PID: 23936 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.name.firstapp/com.example.name.firstapp.MainActivity}: android.os.NetworkOnMainThreadException at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) at android.app.ActivityThread.-wrap11(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:148) at android.app.ActivityThread.main(ActivityThread.java:5417) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$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 com.android.okhttp.internal.Network$1.resolveInetAddresses(Network.java:29) at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:188) at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:157) at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:100) at com.android.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:357) at com.android.okhttp.internal.http.HttpEngine.nextConnection(HttpEngine.java:340) at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:330) at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:248) at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:433) at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:114) at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.connect(DelegatingHttpsURLConnection.java:89) at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java) at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:563) at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:540) at org.jsoup.helper.HttpConnection.execute(HttpConnection.java:227) at org.jsoup.helper.HttpConnection.get(HttpConnection.java:216) at com.example.name.firstapp.MainActivity.onCreate(MainActivity.java:25) at android.app.Activity.performCreate(Activity.java:6237) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) at android.app.ActivityThread.-wrap11(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) at android.os.Handler.dispatchMessage(Handler.java:102) 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)

Bob Bob · Accepted Answer · 2016-04-28T12:04:31

You are connecting to network in the main(UI) thread. So you get android.os.NetworkOnMainThreadException.

Android system wont allow that, as it blocks the UI thread. So Use some background threads like AsyncTask or IntentService to access network.

Android Studio Webview with Custom CSS (jsoup)

1 Answers