解析JSON数据，加载到ListView一片空白

Question

这是主Activity：

public class ListViewDownLoad extends Activity{

private ListView mListView;

private static String URL="www.imooc.com/api/teacher?type=4&num=30";

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

setContentView(R.layout.list_view);

mListView=(ListView) findViewById(R.id.lv_main);

new NewsAsyncTask().execute(URL);

}

private String readStream(InputStream is){

InputStreamReader isr;

String result="";

try {

String line="";

isr = new InputStreamReader(is,"utf-8");

BufferedReader br=new BufferedReader(isr);

while((line = br.readLine())!=null){

result+=line;

}

}catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return result;

}

class NewsAsyncTask extends AsyncTask<String,Void,List<NewsBean>>{

@Override

protected List<NewsBean> doInBackground(String... arg0) {

List<NewsBean> newsBeanList = new ArrayList<NewsBean>();

try {

String jsonString = readStream(new URL(arg0[0]).openStream());

JSONObject jsonObject;

NewsBean newsBean;

jsonObject = new JSONObject(jsonString);

JSONArray jsonArray = jsonObject.getJSONArray("data");

for (int i = 0; i < jsonArray.length(); i++) {

jsonObject = jsonArray.getJSONObject(i);

newsBean = new NewsBean();

newsBean.newsIconUrl=jsonObject.getString("picSmall");

newsBean.newsTitle=jsonObject.getString("name");

newsBean.newsContent=jsonObject.getString("description");

newsBeanList.add(newsBean);

}

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (JSONException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

System.out.println(newsBeanList);

return newsBeanList;

}

@Override

protected void onPostExecute(List<NewsBean> result) {

// TODO Auto-generated method stub

super.onPostExecute(result);

NewsAdapter adapter = new NewsAdapter(ListViewDownLoad.this, result);

mListView.setAdapter(adapter);

}

}

}

这是适配器：

public class NewsAdapter extends BaseAdapter{

private List<NewsBean> mList;

private LayoutInflater mInflater;

public NewsAdapter(Context context,List<NewsBean> data){

mList = data;

mInflater = LayoutInflater.from(context);

}

@Override

public int getCount() {

// TODO Auto-generated method stub

return mList.size();

}

@Override

public Object getItem(int position) {

// TODO Auto-generated method stub

return mList.get(position);

}

@Override

public long getItemId(int position) {

// TODO Auto-generated method stub

return position;

}

@Override

public View getView(int position, View convertView, ViewGroup parent) {

        ViewHolder viewHolder = null;

        if (convertView==null) {

viewHolder = new ViewHolder();

convertView = mInflater.inflate(R.layout.item_layout, null);

viewHolder.ivIcon = (ImageView) convertView.findViewById(R.id.iv_icon);

viewHolder.tvTitle = (TextView) convertView.findViewById(R.id.tv_title);

viewHolder.tvContent = (TextView) convertView.findViewById(R.id.tv_content);

convertView.setTag(viewHolder);

}else{

viewHolder = (ViewHolder) convertView.getTag();

}

        viewHolder.ivIcon.setImageResource(R.drawable.ic_launcher);

        viewHolder.tvTitle.setText(mList.get(position).newsTitle);

        viewHolder.tvContent.setText(mList.get(position).newsContent);

return convertView;

}

class ViewHolder{

public TextView tvTitle;

public TextView tvContent;

public ImageView ivIcon;

}

}

Answer 1

还没解决吗我运行也是白板

Answer 2

访问不了

Answer 3

我也遇到这个问题了，请问题主解决了嘛。？能说一下是怎么解决的嘛？

Answer 4

mList = data;这个data有值吗？