由于某些奇怪的原因，我的RecyclerView返回布尔值'true'。
我似乎无法解决这个问题
This is the output I am getting
它应该显示来自JSON的文本
JSON LINK - https://newsapi.org/v2/top-headlines?sources=cnn&apiKey=c80ddd850a524fe5975cad881d6f4aba
我正在访问'articles'JSON数组，我想显示标题
MainActivity代码：
public class MainActivity extends AppCompatActivity {
RecyclerView mRecyclerView;
private RecyclerView.LayoutManager mLayoutManager;
MyAdapter mViewAdapter;
List<News> news_list = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new ParseNewsJSON().execute();
mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);
mRecyclerView.setHasFixedSize(true);
//mRecyclerView.setItemAnimator(new DefaultItemAnimator());
mRecyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
mViewAdapter = new MyAdapter(new ArrayList<News>());
mRecyclerView.setAdapter(mViewAdapter);
}
public class ParseNewsJSON extends AsyncTask<String, Void, String> {
private final String JSON_URL = "https://newsapi.org/v2/top-headlines?sources=cnn&apiKey=c80ddd850a524fe5975cad881d6f4aba";
String result = "";
ArrayList<String> article_heading = new ArrayList<>();
@Override
protected String doInBackground(String... strings) {
try {
URL url = new URL(JSON_URL);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = httpURLConnection.getInputStream();
InputStreamReader reader = new InputStreamReader(inputStream);
int data = reader.read();
while (data != -1) {
char current = (char) data;
result += current;
data = reader.read();
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return result;
}
protected void onPostExecute(String s) {
try {
JSONObject jsonObject = new JSONObject(result);
JSONArray jsonArray = jsonObject.getJSONArray("articles");
for (int i = 0; i < jsonArray.length(); i++) {
News news = new News();
news.setHeading(String.valueOf(article_heading.add(jsonArray.getJSONObject(i).optString("title"))));
// article_heading.add(jsonArray.getJSONObject(i).optString("title"));
Log.d("news_JSON", article_heading.toString());
Log.d("news", news.getHeading().toString());
news_list.add(news);
}
} catch (JSONException e) {
e.printStackTrace();
}
mViewAdapter = new MyAdapter(news_list);
mRecyclerView.setAdapter(mViewAdapter);
mViewAdapter.notifyDataSetChanged();
super.onPostExecute(s);
}
}
}
MyAdapter代码：
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private List<News> newsArticleList;
public class ViewHolder extends RecyclerView.ViewHolder{
public TextView title;
//description, genre;
public ViewHolder(View itemView) {
super(itemView);
title = (TextView) itemView.findViewById(R.id.textView_articleHeading);
// description = (TextView) itemView.findViewById(R.id.textView_description);
// image = (TextView) itemView.findViewById(R.id.rating);
}
}
public MyAdapter (List<News> newsArticleList){
this.newsArticleList = newsArticleList;
}
@Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.content_main, parent, false);
return new ViewHolder(itemView);
}
@Override
public void onBindViewHolder(MyAdapter.ViewHolder holder, int position) {
News news = newsArticleList.get(position);
holder.title.setText(news.getHeading());
}
@Override
public int getItemCount() {
return newsArticleList.size();
}
}
news.Java;
public class News {
private String heading;
//private String descrpiton;
private String img;
public String getHeading() {
return heading;
}
public void setHeading(String heading) {
this.heading = heading;
}
public String getImg() {
return img;
}
public void setImg(String img) {
this.img = img;
}
}
你的问题在这里
news.setHeading(String.valueOf(article_heading.add(jsonArray.getJSONObject(i).optString("title"))));
article_heading是一个ArrayList，方法add返回一个布尔值，表示列表是否因为你的调用而改变了。
您没有添加标题，您正在添加ArrayList方法的返回，您需要将该行更改为该方法
String title = jsonArray.getJSONObject(i).optString("title");
article_heading.add(title);
news.setHeading(title);
更改你的onPostExecute如下
protected void onPostExecute(String s) {
try {
JSONObject jsonObject = new JSONObject(result);
JSONArray jsonArray = jsonObject.getJSONArray("articles");
for (int i = 0; i < jsonArray.length(); i++) {
News news = new News();
String headingFromJson = jsonArray.getJSONObject(i).getString("title");
article_heading.add(headingFromJson);
news.setHeading(headingFromJson);
// article_heading.add(jsonArray.getJSONObject(i).optString("title"));
Log.d("news_JSON", article_heading.toString());
Log.d("news", news.getHeading().toString());
news_list.add(news);
}
} catch (JSONException e) {
e.printStackTrace();
}
mViewAdapter = new MyAdapter(news_list);
mRecyclerView.setAdapter(mViewAdapter);
mViewAdapter.notifyDataSetChanged();
super.onPostExecute(s);
}
您正在以错误的方式设置新闻标题。
您应该在Asynctask中执行以下操作：
news.setHeading(jsonArray.getJsonObject(i).getString("title"));
而是使用add方法将标题放在arraylist中。并将add方法的结果作为标题。 arraylist的add方法返回一个布尔值，指示列表的添加是否成功。因此，您将继续变为真实而不是实际文本
试试这个：
在你的Parse JSON类qazxsw poi中
改成 ：
onpostexecute()代替：
for (int i = 0; i < jsonArray.length(); i++) {
News news = new News();
news.setHeading(jsonArray.getJSONObject(i).optString("title"));
news_list.add(news);
}