WebView

public class MainActivity extends AppCompatActivity {

    private WebView web;
    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        web = (WebView) findViewById(R.id.web);

        WebSettings WebSetting = web.getSettings();
        WebSetting.setJavaScriptEnabled(true);
        web.setWebViewClient(new WebViewClient());
        web.loadUrl("https://www.facebook.com/");

    }

    @Override    public void onBackPressed() {
        if(web.canGoBack()){
            web.goBack();
        }
        else        {
            super.onBackPressed();
        }
    }
}