我试图创建一个AsyncTask来从服务器端获取一些数据.但是它在onPostExecute()的行中报告了一个Null指针异常“IoUtils.copy((response_.getEntity().getContent()),writer);”我使用一些日志来查看发生了什么,发现日志1和3被打印但log 2没有.为什么在client.executed()完成之前执行了onPostExecute？有人可以给点建议吗？
private class GetForm extends AsyncTask<String,Integer,Object> {
private HttpResponse response_;
private Exception exception_;
private String url_;
public GetForm(String url) {
super();
url_ = url;
}
protected Object doInBackground(String... params) {
try {
Log.i("mylog","inside doInbackground 1.");
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet(url_);
response_ = client.execute(request);
Log.i("mylog","inside doInbackground 2.");
} catch (Exception e) {
exception_ = e;
}
return response_;
}
@Override
protected void onPostExecute(Object o) {
// Your current UI stuff here.
Log.i("mylog","inside onPostExecute 3.");
StringWriter writer = new StringWriter();
try{
IoUtils.copy((response_.getEntity().getContent()),writer);
......
}catch(IOException e) {
e.printStackTrace();
}
}
}
