我一直不明白 就这几行代码 单独在一个工程可以,就这么复制黏贴就爆空指针异常,我真的,已经陷入无限循环两天了
求大神指点迷津
上代码
public class Personlogin1 extends Activity {
private HttpClient client = null;
private Button on_login;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_personlogin1);
on_login = (Button) findViewById(R.id.onlogin);
on_login.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
readNet("http://www.weather.com.cn/adat/cityinfo/101010100.html");
}
public void readNet(String url) {
new AsyncTask<String, Void, String>() {
@Override
protected String doInBackground(String... arg0) {
System.out.println("1");
String urlString = arg0[0];
System.out.println("2");
HttpGet get = new HttpGet(urlString);
try {
System.out.println("3");
HttpResponse response = client.execute(get);
System.out.println("4");
String value = EntityUtils.toString(response.getEntity());
System.out.println("44444444"+value);
System.out.println("5");
return value;
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
System.out.println("6");
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
System.out.println("7");
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String result) {
System.out.println(result);
}
}.execute(url);
}
});
代码就这些 ![图片说明](https://img-ask.csdn.net/upload/201601/25/1453723473_824864.png)