1
我正在使用TheMovieDB API加载流行电影的图像并将其显示在网格视图中的应用程序（以及其他内容，但此时并不重要） i'米面临的这些错误，我需要帮助来解决them..here是错误使用ImageViews填充底座适配器
enter image description here 这里的快照是MovieAdapter.java
package com.example.android.movies;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import com.squareup.picasso.Picasso;
import java.util.ArrayList;
/**
*
*/
public class MovieAdapter extends BaseAdapter{
ArrayList<Movies> MovieList;
Context mContext;
public MovieAdapter(Context context,ArrayList<Movies> movieArrayList) {
this.mContext=context;
this.MovieList=movieArrayList;
}
@Override
public int getCount() {
return MovieList == null ? 0 : MovieList.size();
}
@Override
public Object getItem(int position) {
return MovieList.get(position);
}
@Override
public long getItemId(int id) {return MovieList.get(id).getMposter_id(); }
@Override
public View getView(int position, View ConvertedView, ViewGroup viewGroup) {
View view=ConvertedView;
if (view==null)
{
LayoutInflater inflater=(LayoutInflater)
mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view=inflater.inflate(R.layout.grid_item,null);
}
ImageView ivMovieName= (ImageView) view.findViewById(R.id.image_view);
Picasso.with(mContext)
.load("http://image.tmdb.org/t/p/w185"+MovieList.get(position).getMposter_path()).into(ivMovieName);
return view;
}
}
这里MainActivityFragment
package com.example.android.movies;
import android.content.Context;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.GridView;
import android.widget.ImageView;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.ProtocolException;
import java.net.URL;
import java.util.ArrayList;
/**
* A placeholder fragment containing a simple view.
*/
public class MainActivityFragment extends Fragment {
//private final String LOG_TAG = FetchMovieData.class.getSimpleName();
JSONObject jsonObject;
JSONArray jArray;
ArrayList<Movies> MovieArrayList;
String Poster_Path; //poster url
String movieTitle, overview, date;
Double vote;
Long Poster_ID;
MovieAdapter Adapter;
GridView gridview;
ImageView image;
public MainActivityFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
gridview = (GridView) rootView.findViewById(R.id.gridview);
//Register a callback to be invoked when an item in this AdapterView has been clicked.
gridview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
//String forecast = (String) Adapter.getItem(i);
Movies m = MovieArrayList.get(i);
Long Movie_ID = m.getMposter_id();
String Poster_URL = m.getMposter_path();
/* String Movie_Title = m.getMtitle();
String Movie_Date = m.getMdate();
String Movie_Overview = m.getMoverview();
Double Movie_Vote = m.getMvote();*/
Intent intent = new Intent(getActivity(), Details.class);
intent.putExtra("id", Movie_ID);
intent.putExtra("poster_path", Poster_URL);
/* intent.putExtra("title", Movie_Title);
intent.putExtra("overview", Movie_Overview);
intent.putExtra("release_date", Movie_Date);
intent.putExtra("vote_average", Movie_Vote);*/
startActivity(intent);
}
});
return rootView;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setHasOptionsMenu(true);
new FetchMovieData(getActivity()).execute();
}
public class FetchMovieData extends AsyncTask<String, Void, ArrayList<Movies>> {
public Context context;
public FetchMovieData(Context context) {
this.context = context;
}
@Override
protected ArrayList<Movies> doInBackground(String... params) {
// If there's no zip code, there's nothing to look up. Verify size of params.
if (params.length == 0) {
return null;
}
HttpURLConnection urlConnection=null;
BufferedReader reader=null;
/*Will contain the raw JSON response as a string.
String movieJsonStr = null;*/
try {
final String mostPopularURL = "https://api.themoviedb.org/3/movie/popular?api_key=4843589caabdf86860e4e0a054175d02";
final String highestRatedURL = "https://api.themoviedb.org/3/movie/top_rated?api_key=4843589caabdf86860e4e0a054175d02";
URL url = new URL(mostPopularURL); //to read more than 1 URL
//create the request & open connection
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");//method used for the server GET DATA
urlConnection.connect();
//read input stream into string
InputStream inputStream = urlConnection.getInputStream(); //can't read line by line so we should use bufferReader
StringBuffer buffer = new StringBuffer();
if (inputStream == null) {
// Nothing to do.
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));//data of type JSON
String strReader;
while ((strReader = reader.readLine()) != null) {
// Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
// But it does make debugging a *lot* easier if you print out the completed
// buffer for debugging.
buffer.append(strReader + "\n");
}
if (buffer.length() == 0) {
// Stream was empty. No point in parsing.
return null;
}
//movieJsonStr = buffer.toString();
jsonObject = new JSONObject(strReader);
jArray = jsonObject.getJSONArray("results");
MovieArrayList = new ArrayList<>();
//Array named result {from json formatter}
//3shan 2wsl ll obejects gowa l array
for (int i = 0; i < jArray.length(); i++) {
jsonObject = jArray.getJSONObject(i);
//3shn a-access kol 7aga gowa l object poster path
Poster_Path = jsonObject.getString("poster_path");
Poster_ID = jsonObject.getLong("id");
/* movieTitle = jsonObject.getString("title");
overview = jsonObject.getString("overview");
date = jsonObject.getString("release_date");
vote = jsonObject.getDouble("vote_average");*/
//to get poster path & poster id and put them in json object
Movies movieObj = new Movies(Poster_Path, Poster_ID);
movieObj.setMposter_path(Poster_Path);
movieObj.setMposter_id(Poster_ID);
/* movieObj.setMdate(date);
movieObj.setMoverview(overview);
movieObj.setMtitle(movieTitle);
movieObj.setMvote(vote);*/
MovieArrayList.add(movieObj);
}
inputStream.close();
return MovieArrayList;
} catch (ProtocolException e) {
Log.e("FetchMovieData", "error", e);
} catch (IOException e) {
Log.e("FetchMovieData", "error", e);
} catch (JSONException e) {
Log.e("FetchMovieData", "error", e);
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {///////////////??
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return MovieArrayList;
}
@Override
protected void onPostExecute(final ArrayList<Movies> MovieArrayList) {
Adapter = new MovieAdapter(getActivity(),MovieArrayList);//////////////////????
gridview.setAdapter(Adapter);
}
}
}
可能重复[什么是NullPointerException，以及如何解决它？]（http://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-doi-i-fix -it） –