Android ViewPager very unusual behavior on scrolling between pages

Question

I have created view pager and scrolling between pages (i.e. fragment). Content of the current page sticks to the display while the next screen content scrolls into the display.

Here is my Adapter:

public class ViewPagerAdapter extends FragmentStatePagerAdapter {
  private int numPages;

  public ViewPagerAdapter(FragmentManager fm, int numPages) {
    super(fm);
    this.numPages = numPages;
  }

  @Override
  public Fragment getItem(int position) {
    switch (position){
        case 0:
            return WeatherFragment.newInstance();
        case 1:
            return NewsFragment.newInstance();
        case 2:
            return CalenderFragment.newInstance();
        case 3:
            return MusicFragment.newInstance();
        default:
            return null;
    }
  }

  @Override
  public int getCount() {
      return this.numPages;
  }
}

Here is my Weather Fragment:

public class WeatherFragment extends Fragment {
Context mContext;
Utility utility;
private static final String TAG = "WeatherFragment";


public static WeatherFragment newInstance() {

    Bundle args = new Bundle();

    WeatherFragment fragment = new WeatherFragment();
    fragment.setArguments(args);
    return fragment;
}

@Override
public void onAttach(Context context) {
    super.onAttach(context);
    utility = Utility.getInstance(getActivity());
}

ImageView weather_image;
TextView weather_temp, weather_des, weather_wind, weather_elevation, weather_humidity, weather_visibility;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    ViewGroup root = (ViewGroup) inflater.inflate(R.layout.weather_layout, container, false);

    weather_image = (ImageView) root.findViewById(R.id.weather_image);
    weather_temp  = (TextView) root.findViewById(R.id.weather_temp);
    weather_des  = (TextView) root.findViewById(R.id.weather_description);
    weather_wind  = (TextView) root.findViewById(R.id.weather_wind);
    weather_elevation  = (TextView) root.findViewById(R.id.weather_elevation);
    weather_humidity  = (TextView) root.findViewById(R.id.weather_humidity);
    weather_visibility  = (TextView) root.findViewById(R.id.weather_visibility);


    getLocation();

    return root;
}

private void getLocation(){
    utility.jsonObjectRequest(Config.GET_LOCATION_URL, new VolleyCallback() {
        @Override
        public void onSuccess(JSONObject response) {
            IpLocation location = new IpLocation();
            try {
                location.setCity(response.getString("city"));
                location.setIp(response.getString("ip"));
                location.setRegion(response.getString("region"));
                location.setCountry(response.getString("country"));
                location.setLoc(response.getString("loc"));
                location.setOrg(response.getString("org"));

                getWeather(location);

            } catch (JSONException e) {
                e.printStackTrace();
                Snacky.builder().setActivty(getActivity())
                        .setText("In Valid Response")
                        .setDuration(Snacky.LENGTH_SHORT)
                        .warning();
            }
        }

        @Override
        public void onFailure(VolleyError error) {
            Snacky.builder().setActivty(getActivity())
                    .setText("No Internet Connection")
                    .setDuration(Snacky.LENGTH_SHORT)
                    .error();
        }
    });
}

@Override
public void onDestroy() {
    super.onDestroy();
}

private void getWeather(IpLocation location){
    utility.jsonObjectRequest(Config.GET_WEATHER_URL_BASE + location.getLoc() + ".json", new VolleyCallback() {
        @Override
        public void onSuccess(JSONObject res) {
            Weather weather = new Weather();
            try {
                JSONObject response = res.getJSONObject("current_observation");
                JSONObject observationData = response.getJSONObject("observation_location");
                weather.setOb_full(observationData.getString("full"));
                weather.setOb_city(observationData.getString("city"));
                weather.setOb_country(observationData.getString("country"));
                weather.setOb_state(observationData.getString("state"));
                weather.setOb_lat(observationData.getString("latitude"));
                weather.setOb_long(observationData.getString("longitude"));
                weather.setOb_elevation(observationData.getString("elevation"));

                weather.setOb_time(response.getString("observation_time"));
                weather.setWeather(response.getString("weather"));
                weather.setTemp_c(response.getString("temp_c"));
                weather.setRelative_humidity(response.getString("relative_humidity"));
                weather.setWind_string(response.getString("wind_string"));
                weather.setWind_dir(response.getString("wind_dir"));
                weather.setWind_degrees(response.getString("wind_degrees"));
                weather.setWind_mph(response.getString("wind_mph"));
                weather.setWind_kph(response.getString("wind_kph"));
                weather.setPressure_in(response.getString("pressure_in"));
                weather.setPressure_mb(response.getString("pressure_mb"));
                weather.setPressure_trend(response.getString("pressure_trend"));
                weather.setDewpoint_c(response.getString("dewpoint_c"));
                weather.setHeat_index_c(response.getString("heat_index_c"));
                weather.setWindchill_c(response.getString("windchill_c"));
                weather.setWindchill_string(response.getString("windchill_string"));
                weather.setFeelslike_c(response.getString("feelslike_c"));
                weather.setVisibility_km(response.getString("visibility_km"));
                weather.setSolar_radiation(response.getString("solarradiation"));
                weather.setPrecip_today_in(response.getString("precip_today_in"));
                weather.setIcon(response.getString("icon"));
                weather.setIcon_url(response.getString("icon_url"));

                showWeatheronUI(weather);

            } catch (JSONException e) {
                e.printStackTrace();
                Snacky.builder().setActivty(getActivity())
                        .setText("In Valid Response")
                        .setDuration(Snacky.LENGTH_SHORT)
                        .warning();
            }
        }

        @Override
        public void onFailure(VolleyError error) {
            Snacky.builder().setActivty(getActivity())
                    .setText("No Internet Connection")
                    .setDuration(Snacky.LENGTH_SHORT)
                    .error();
        }
    });
}

private void showWeatheronUI(Weather weather){
    if(!this.isDetached()){
        Glide.with((Fragment)this)
                .load(weather.getIcon_url())
                .into(weather_image);

    }

    weather_des.setText(weather.getWeather());
    weather_temp.setText(weather.getTemp_c() + "˚C");
    weather_wind.setText(weather.getWind_string());
    weather_humidity.setText("Humidity: " + weather.getRelative_humidity());
    weather_visibility.setText(weather.getVisibility_km() + " Km");
    weather_elevation.setText(weather.getOb_elevation());
}
}

Here is my News Fragment:

public class NewsFragment extends Fragment {
TextView news_list;
Utility utility;


public static NewsFragment newInstance() {

    Bundle args = new Bundle();

    NewsFragment fragment = new NewsFragment();
    fragment.setArguments(args);
    return fragment;
}

@Override
public void onAttach(Context context) {
    super.onAttach(context);
    utility = Utility.getInstance(getActivity());

}

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    ViewGroup root = (ViewGroup) inflater.inflate(R.layout.news_layout, container, false);

    news_list = (TextView) root.findViewById(R.id.news_list);

    fetchNews();

    return root;
}


private void showNewsOnUI(String text){
    news_list.setText(text);
}

private void fetchNews(){
    utility.jsonObjectRequest(Config.GET_NEWS_URL, new VolleyCallback() {
        @Override
        public void onSuccess(JSONObject response) {
            try {
                JSONArray articles = response.getJSONArray("articles");

                String news_text ="";

                for(int i=0;i<articles.length();i++){
                    JSONObject article = (JSONObject) articles.get(i);
                    News newt = new News();
                    newt.setTitle(article.getString("title"));
                    newt.setAuthor(article.getString("author"));
                    newt.setDescription(article.getString("description"));
                    newt.setUrl(article.getString("url"));
                    newt.setUrlToImage(article.getString("urlToImage"));
                    newt.setPublishedOn(article.getString("publishedAt"));

                    news_text += newt.getTitle() + "\n";
                }

                showNewsOnUI(news_text);


            } catch (JSONException e) {
                e.printStackTrace();
                Snacky.builder().setActivty(getActivity())
                        .setText("Invalid Response Recieved")
                        .setDuration(Snacky.LENGTH_SHORT)
                        .error();
            }
        }

        @Override
        public void onFailure(VolleyError error) {
            Snacky.builder().setActivty(getActivity())
                    .setText("No Internet Connection")
                    .setDuration(Snacky.LENGTH_SHORT)
                    .error();
        }
    });
}
}

Here is MainActivity where Adapter is called:

OnCreate(){
  ...
  mPageAdapter = new ViewPagerAdapter(getSupportFragmentManager(), NUM_PAGES); // NUM_PAGES=4
  viewPager.setAdapter(mPageAdapter);
  ...
}

If a press app switcher and select the same app then it view appears to be fine. Here is what News Fragment Looks like i.e. Page 2 in View Pager. after selecting same app in app switcher:

Edit:

Here is my style.xml file:

<resources>

<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
    <item name="android:textViewStyle">@style/MyTextViewStyle</item>
</style>

<style name="FullscreenTheme" parent="AppTheme">
    <item name="android:actionBarStyle">@style/FullscreenActionBarStyle</item>
    <item name="android:windowActionBarOverlay">true</item>
    <item name="android:windowBackground">@null</item>
    <item name="metaButtonBarStyle">?android:attr/buttonBarStyle</item>
    <item name="metaButtonBarButtonStyle">?android:attr/buttonBarButtonStyle</item>
</style>

<style name="MyTextViewStyle" parent="android:Widget.TextView">
    <item name="android:textColor">#f5f5f5</item>
</style>

<style name="FullscreenActionBarStyle" parent="Widget.AppCompat.ActionBar">
    <item name="android:background">@color/black_overlay</item>
</style>

I would bet this has something to do with your window background. Post your styles/themes and layouts. — adneal, Jul 21 '17 at 19:39

Android ViewPager very unusual behavior on scrolling between pages

0 Answers0