所以我在json响应的gridview中显示图像。
每张图片都有一个json响应，如：
{poster_path=/u1LHo5ObRZA1r8pzSq0OqQ2qlaU.jpg, vote_average=0.0, title=The Beauty Inside, vote_count=0, overview=Woo-Jin changes into a different person when he wakes up. He falls in love with Yi-Soo., id=338729, release_date=2015-08-20}
poster_path包含图片网址。
当poster_path为null时，如：
{poster_path=null, vote_average=0.0, title=The Bad Education Movie, vote_count=0, overview=Mr Wickers and his class go on one final school trip after they finish their GCSEs., id=348296, release_date=2015-08-21}
我想删除Hashmap中的这个项目，如果它包含poster_path = null，那么它不会将该数据加载到我的gridView中。
如何做到这一点？
这是我的活动，它下载并解析json响应：
public class Upcoming extends android.support.v4.app.Fragment {
private static final String KEY_POSITION = "position";
private static final String TAGG = "TMDB Pop Movies";
private static final String apiKey = "MYKEY";
private static final String tmdbURL = "MYURL";
private static final String TAG_MOVIES = "results";
static final String TAG_ID = "id";
static final String TAG_RELEASE = "release_date";
static final String TAG_TITLE = "title";
static final String TAG_POSTER = "poster_path";
static final String TAG_VOTE_AVG = "vote_average";
static final String TAG_VOTE_COUNT = "vote_count";
static final String TAG_OVERVIEW = "overview";
String NumberOfPage = "&page=1";
ArrayList<HashMap<String, String>> mylist;
JSONObject json = null;
JSONArray results = null;
UpcomingGridViewAdapter adapter;
GridView Gridv;
int numberofpagesshown = 0;
private String position;
private OnFragmentInteractionListener mListener;
public static Upcoming newInstance(int position) {
Upcoming fragment = new Upcoming();
Bundle args = new Bundle();
args.putInt(KEY_POSITION, position);
fragment.setArguments(args);
return fragment;
}
public Upcoming() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
position = getArguments().getString(KEY_POSITION);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
final View newview = inflater.inflate(R.layout.fragment_upcoming, container, false);
//Initialize with empty data
mylist = new ArrayList<HashMap<String, String>>();
// Start download void
new DownloadJSON().execute();
return newview;
}
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mListener = (OnFragmentInteractionListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
public void onFragmentInteraction(Uri uri);
}
// Downloading data asynchronously
private class DownloadJSON extends AsyncTask<String, String, String> {
@Override
protected String doInBackground(String... url) {
json = JSONfunctions.getJSONfromURL(tmdbURL + "/3/movie/upcoming"
+ apiKey + NumberOfPage);
try {
// Get the array of movies
results = json.getJSONArray(TAG_MOVIES);
// loop through all the movies
for (int i = 0; i < results.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
JSONObject r = results.getJSONObject(i);
String id = r.getString(TAG_ID);
String title = r.getString(TAG_TITLE);
String poster = r.getString(TAG_POSTER);
String release = r.getString(TAG_RELEASE);
String vote = r.getString(TAG_VOTE_AVG);
String voteCount = r.getString(TAG_VOTE_COUNT);
String overview = r.getString(TAG_OVERVIEW);
map.put(TAG_ID, id);
map.put(TAG_TITLE, title);
map.put(TAG_POSTER, poster);
map.put(TAG_RELEASE, release);
map.put(TAG_VOTE_AVG, vote);
map.put(TAG_VOTE_COUNT, voteCount);
map.put(TAG_OVERVIEW, overview);
mylist.add(map);
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
numberofpagesshown = numberofpagesshown + 1;
if(numberofpagesshown == 1 ) {
Gridv = (GridView) getActivity().findViewById(R.id.upcoming_gridlayout);
adapter = new UpcomingGridViewAdapter(getActivity(), mylist);
Gridv.setAdapter(adapter);
}
else {
adapter.notifyDataSetChanged();
}
// Attach the listener to the AdapterView onCreate
Gridv.setOnScrollListener(new EndlessScrollListener() {
@Override
public void onLoadMore(int page, int totalItemsCount) {
// Triggered only when new data needs to be appended to the list
// Append new items to AdapterView
if (numberofpagesshown == 1) {
NumberOfPage = "&page=2";
new DownloadJSON().execute();
} else if (numberofpagesshown == 2) {
NumberOfPage = "&page=3";
new DownloadJSON().execute();
} else if (numberofpagesshown == 3) {
NumberOfPage = "&page=4";
new DownloadJSON().execute();
} else if (numberofpagesshown == 4) {
NumberOfPage = "&page=5";
new DownloadJSON().execute();
} else if (numberofpagesshown == 5) {
NumberOfPage = "&page=6";
new DownloadJSON().execute();
}
}
});
}
}
}
最后是gridView适配器：
public class UpcomingGridViewAdapter extends BaseAdapter {
public boolean pressedMovieItem;
Context context;
ArrayList<HashMap<String, String>> data;
// Will store json data
HashMap<String, String>mylist = new HashMap<>();
public UpcomingGridViewAdapter(Context a, ArrayList<HashMap<String, String>> d) {
context = a;
data = d;
}
public int getCount() {
return data.size();
}
public HashMap<String, String> getItem(int position) {
return data.get(position);
}
public long getItemId(int position) {
return position;
}
public View getView(final int position, View convertView, ViewGroup parent) {
if (convertView == null){
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.upcoming_grid_item, parent, false);
}
final ImageView poster = (ImageView) convertView.findViewById(R.id.upcoming_image);
mylist = data.get(position);
final String posterPath = mylist.get("poster_path");
// set image url correctly
// sizes for image 45, 92, 154, 185, 300, 500
final String url = "http://image.tmdb.org/t/p/w185" + posterPath;
if(mylist.get("poster_path") != "null") {
// load image url into poster
Picasso.with(context).load(url).into(poster);
}
else{
// load image url into poster
// Picasso.with(context).load(R.drawable.ic_local_movies_black_24dp).into(poster);
poster.setBackgroundColor(Color.parseColor("#F5F5F5"));
// poster.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
}
}
答案 0 :(得分：1)
只需改变你在doInBackground()内的循环就像这样。它只是不会在ArrayList
for (int i = 0; i < results.length(); i++)
{
HashMap<String, String> map = new HashMap<String, String>();
JSONObject r = results.getJSONObject(i);
String poster = r.getString(TAG_POSTER);
if(poster == null || poster.equals(""))
continue;
String id = r.getString(TAG_ID);
String title = r.getString(TAG_TITLE);
String release = r.getString(TAG_RELEASE);
String vote = r.getString(TAG_VOTE_AVG);
String voteCount = r.getString(TAG_VOTE_COUNT);
String overview = r.getString(TAG_OVERVIEW);
map.put(TAG_ID, id);
map.put(TAG_TITLE, title);
map.put(TAG_POSTER, poster);
map.put(TAG_RELEASE, release);
map.put(TAG_VOTE_AVG, vote);
map.put(TAG_VOTE_COUNT, voteCount);
map.put(TAG_OVERVIEW, overview);
mylist.add(map);
}
答案 1 :(得分：0)
做了一点修改：
// loop through all the movies
for (int i = 0; i < results.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
JSONObject r = results.getJSONObject(i);
String poster = r.getString(TAG_POSTER);
if(poster == null || poster.equals("")|| poster.equals("null"))
continue;
else {
String id = r.getString(TAG_ID);
String title = r.getString(TAG_TITLE);
String release = r.getString(TAG_RELEASE);
String vote = r.getString(TAG_VOTE_AVG);
String voteCount = r.getString(TAG_VOTE_COUNT);
String overview = r.getString(TAG_OVERVIEW);
map.put(TAG_ID, id);
map.put(TAG_TITLE, title);
map.put(TAG_POSTER, poster);
map.put(TAG_RELEASE, release);
map.put(TAG_VOTE_AVG, vote);
map.put(TAG_VOTE_COUNT, voteCount);
map.put(TAG_OVERVIEW, overview);
mylist.add(map);
}