Debug后 Str为null list.size（）为空指针？
URL httpUrl;
try {
httpUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection) httpUrl.openConnection();
conn.setReadTimeout(5000);
conn.setRequestMethod("GET");
BufferedReader reader=new BufferedReader(new InputStreamReader(conn.getInputStream()));
StringBuffer sb=new StringBuffer();
System.out.println(""+reader.readLine());
String str; //这边为空
while ((str=reader.readLine())!=null) {
sb.append(str);
}
System.out.println(""+sb.toString());
final List<Person> data=parseJson(sb.toString());
handler.post(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
adapter.setData(data);
listView.setAdapter(adapter);
}
});还有就是list.size（）为空指针。
java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
