我从theMovieDb.com获取数据。在设置菜单中，它有按最热门或最高评级排序的选项。用户选择他的偏好后，我想自动刷新主要活动。我尝试了几件事，但对我没什么用。
MainActivityFragment.java
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
volleySingleton = VolleySingleton.getInstance();
requestQueue = volleySingleton.getRequestQueue();
sendJsonRequest();
}
// To initialize the Image Adapter
public ImageAdapter initializeAdapter() {
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
String sortby = preferences.getString(getString(R.string.pref_key), getString(R.string.pref_default_value));
if (sortby.equals(getString(R.string.pref_rating))) {
mAdapter = new ImageAdapter(getActivity(), sortListRating);
} else if (!sortby.equals(getString(R.string.pref_rating))) {
mAdapter = new ImageAdapter(getActivity(), listMovie);
}
return mAdapter;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
GridView gridView = (GridView) rootView.findViewById(R.id.grid_view_movies);
final ImageAdapter mFinalAdapter = initializeAdapter();
gridView.setAdapter(mFinalAdapter);
gridView.setOnItemClickListener(new AdapterView.OnItemClickListener()
{
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
Movie movieSelected = listMovie.get(position);
String movieTitle = movieSelected.getTitle();
String movieThumbnail = movieSelected.getUrlThumbnail();
String movieReleaseDate = movieSelected.getReleaseDate();
String movieOverview = movieSelected.getOverview();
String movieRating = movieSelected.getRating();
Intent i = new Intent(getActivity(), DetailsMovies.class);
i.putExtra(EXTRA_MESSAGE_1, movieThumbnail);
i.putExtra(EXTRA_MESSAGE_2, movieTitle);
i.putExtra(EXTRA_MESSAGE_3, movieReleaseDate);
i.putExtra(EXTRA_MESSAGE_4, movieRating);
i.putExtra(EXTRA_MESSAGE_5, movieOverview);
startActivity(i);
}
}
);
return rootView;
}
private void sendJsonRequest() {
//In the case of theMovieDB it is JSON Object Request
//Specify several argument in JSON Object Request
JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET,
getRequestUrl(),
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
parseJsonResponse(response);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
requestQueue.add(request);
}
private void parseJsonResponse(JSONObject response) {
if (response == null || response.length() == 0) {
return;
}
long id = -1;
String title = Constants.NA;
String releaseDate = Constants.NA;
String synopsis = Constants.NA;
String urlThumbnail = Constants.NA;
String rating = Constants.NA;
String popularity = Constants.NA;
String votecount = Constants.NA;
try {
if (response.has(KEY_RESULTS)) {
JSONArray jsonArray = response.getJSONArray(KEY_RESULTS);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject currentMovies = jsonArray.getJSONObject(i);
//Get the id of the current movie
//If statement is used to check whether id is null or not.
if (currentMovies.has(KEY_ID) && !currentMovies.isNull(KEY_ID)) {
id = currentMovies.getLong(KEY_ID);
}
//Get the synopsis of the current movie
if (currentMovies.has(KEY_OVERVIEW) && !currentMovies.isNull(KEY_OVERVIEW)) {
synopsis = currentMovies.getString(KEY_OVERVIEW);
}
//Get the title of the current movie
if (currentMovies.has(KEY_TITLE) && !currentMovies.isNull(KEY_TITLE)) {
title = currentMovies.getString(KEY_TITLE);
}
//Get the urlThumbnail of the current movie
if (currentMovies.has(KEY_POSTER_PATH) && !currentMovies.isNull(KEY_POSTER_PATH)) {
urlThumbnail = currentMovies.getString(KEY_POSTER_PATH);
}
//Get the release date of the current movie
if (currentMovies.has(KEY_RELEASE_DATE) && !currentMovies.isNull(KEY_RELEASE_DATE)) {
releaseDate = currentMovies.getString(KEY_RELEASE_DATE);
}
//Get the rating of current movie
if (currentMovies.has(KEY_VOTE_AVERAGE) && !currentMovies.isNull(KEY_VOTE_AVERAGE)) {
rating = currentMovies.getString(KEY_VOTE_AVERAGE);
}
//Get the popularity of the current movie
if (currentMovies.has(KEY_POPULARITY) && !currentMovies.isNull(KEY_POPULARITY)) {
popularity = currentMovies.getString(KEY_POPULARITY);
}
//Get the vote_count of the current movie
if (currentMovies.has(KEY_VOTE_COUNT) && !currentMovies.isNull(KEY_VOTE_COUNT)) {
votecount = currentMovies.getString(KEY_VOTE_COUNT);
}
//Create movie object
movie = new Movie();
movie.setId(id);
movie.setTitle(title);
movie.setUrlThumbnail("http://image.tmdb.org/t/p/w185/" + urlThumbnail);
movie.setReleaseDate(releaseDate);
movie.setOverview(synopsis);
movie.setRating(rating);
movie.setPopularity(popularity);
movie.setVoteCount(votecount);
//This decides when to add movies to the ArrayList
if (id != -1 && !title.equals(Constants.NA)) {
listMovie.add(movie);
sortListRating.add(movie);
}
}
}
Collections.sort(sortListRating);
} catch (JSONException e) {
Log.e("error", e.getMessage());
}
}
public String getRequestUrl() {
//SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(getActivity());
//String order = pref.getString(getString(R.string.pref_order_key), getString(R.string.pref_popularity));
//if(order.equals(getString(R.string.pref_rating)))
// return URL + "vote_average" + UrlEndpoints.URL_PARAM + MyApplication.API_KEY;
//else
return URL + "popularity" + UrlEndpoints.URL_PARAM + MyApplication.API_KEY;
}
//Base Adapter which is used to put poster in grid view
public class ImageAdapter extends BaseAdapter {
private Context mContext;
private ArrayList<Movie> movieItems;
public ImageAdapter(Context c, ArrayList<Movie> movieList) {
this.mContext = c;
this.movieItems = movieList;
}
public int getCount() {
return movieItems.size();
}
public Object getItem(int position) {
return movieItems.get(position);
}
public long getItemId(int position) {
return position;
}
// create a new ImageView for each item referenced by the Adapter
public View getView(int position, View convertView, ViewGroup parent) {
if (inflater == null) {
inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
if (convertView == null) {
convertView = inflater.inflate(R.layout.grid_item_movies, null);
}
mNetworkImageView = (NetworkImageView) convertView.findViewById
(R.id.networkImageView);
//Getting movie data for the row
Movie m = movieItems.get(position);
//Thumbnail Image
//ImageLoader is used to load the images from json object retrieved.
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
String sortby = preferences.getString(getString(R.string.pref_key), getString(R.string.pref_default_value));
if (sortby.equals(getString(R.string.pref_rating))) {
imageLoader = VolleySingleton.getInstance().getImageLoader();
mNetworkImageView.setImageUrl(m.getUrlThumbnail(), imageLoader);
} else if (!sortby.equals(getString(R.string.pref_rating))) {
imageLoader = VolleySingleton.getInstance().getImageLoader();
mNetworkImageView.setImageUrl(m.getUrlThumbnail(), imageLoader);
}
return convertView;
}
}
SettingsActivity.java
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Add 'general' preferences, defined in the XML file
// Added preferences from XML
addPreferencesFromResource(R.xml.pref_general);
// For all preferences, attach an OnPreferenceChangeListener so the UI summary can be
// updated when the preference changes.
// Added preferences
bindPreferenceSummaryToValue(findPreference(getString(R.string.pref_key)));
}
/**
* Attaches a listener so the summary is always updated with the preference value.
* Also fires the listener once, to initialize the summary (so it shows up before the value
* is changed.)
*/
private void bindPreferenceSummaryToValue(Preference preference) {
// Set the listener to watch for value changes.
preference.setOnPreferenceChangeListener(this);
// Trigger the listener immediately with the preference's
// current value.
onPreferenceChange(preference,
PreferenceManager
.getDefaultSharedPreferences(preference.getContext())
.getString(preference.getKey(), ""));
}
@Override
public boolean onPreferenceChange(Preference preference, Object value) {
String stringValue = value.toString();
if (preference instanceof ListPreference) {
// For list preferences, look up the correct display value in
// the preference's 'entries' list (since they have separate labels/values).
ListPreference listPreference = (ListPreference) preference;
int prefIndex = listPreference.findIndexOfValue(stringValue);
if (prefIndex >= 0) {
preference.setSummary(listPreference.getEntries()[prefIndex]);
}
} else {
// For other preferences, set the summary to the value's simple string representation.
preference.setSummary(stringValue);
}
return true;
}
我根据电影的流行度将数据存储在ArrayList中，然后根据评级并存储在新的ArrayList中对相同的数组列表进行排序。如果在更改首选项时如何刷新数据？
答案 0 :(得分：0)
当您恢复活动时，应通知适配器基础数据已更改。你应该使用：
mAdapter.notifyDataSetChanged();