Android: Why does BufferedReader reading a URL cause my app to crash?

My app crashes at line 38 from the log cat I get:

java.lang.IllegalStateException: Could not execute method of the activity

I followed the same instruction from this link http://ift.tt/1iJUvvH so I don't know why line 38 causes the app to crash.

public class MainActivity extends Activity {

    private TextView mInputVal;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mInputVal = (TextView) findViewById(R.id.user_text);
    }


    public void enter_handler(View view){
        String url = mInputVal.getText().toString();
        boolean is_word_there = false;
        try{
            URL readingWeb = new URL(url);
            try{
                BufferedReader in = new BufferedReader(new InputStreamReader(readingWeb.openStream()));//this line crashes
                String line;
                while ((line = in.readLine()) != null) {
                    if(line.contains("tiger")){
                        is_word_there = true;
                        break;
                    }
                }
            }catch(IOException e){
                e.printStackTrace();
            }
        }
        catch(MalformedURLException e){
            e.printStackTrace();
        }
        String text = "";
        if(is_word_there == true){
            text = "true!";
        }
        else{
            text = "false";
        }
        makeToast(text);
    }

    public void makeToast(CharSequence text){
        Context context = getApplicationContext();
        int duration = Toast.LENGTH_SHORT;
        Toast toast = Toast.makeText(context,text,duration);
        toast.show();
    }

}