android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a vi

今天继续在编写app，后来女朋友来消息，按了home将app后台运行，再打开时崩了，

，报了如下错误：

 android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.

大致意思就是，我在非主线程更新ui了，所以崩了

（真特么低级的错误，去年犯的错今年还犯）

private  void setdate() {    new Thread(new Runnable() {        @Override        public void run() {            String strURL = "http://jirenguapi.applinzi.com/weather.php";            URL url = null;            try {                url = new URL(strURL);                HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();                InputStreamReader input = new InputStreamReader(httpConn                        .getInputStream(), "utf-8");                BufferedReader bufReader = new BufferedReader(input);                String line = "";                StringBuilder contentBuf = new StringBuilder();                while ((line = bufReader.readLine()) != null) {                    contentBuf.append(line);                }                date_weather.setText(contentBuf);            } catch (MalformedURLException e) {                e.printStackTrace();            } catch (UnsupportedEncodingException e) {                e.printStackTrace();            } catch (IOException e) {                e.printStackTrace();            }        }    }).start();}


改成如下代码，使用了handler异步更新，测试后不再崩溃，大致原理是在主线程创了一个handler，接收来自子线程的数据并更新ui
private Handler handler_setdate =  new Handler(){    @Override    public void handleMessage(Message msg) {        super.handleMessage(msg);        String message = msg.obj.toString();        date_weather.setText(message);    }};private  void setdate() {    new Thread(new Runnable() {        @Override        public void run() {            String strURL = "http://jirenguapi.applinzi.com/weather.php";            URL url = null;            try {                url = new URL(strURL);                HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();                InputStreamReader input = new InputStreamReader(httpConn                        .getInputStream(), "utf-8");                BufferedReader bufReader = new BufferedReader(input);                String line = "";                StringBuilder contentBuf = new StringBuilder();                while ((line = bufReader.readLine()) != null) {                    contentBuf.append(line);                }                Message msg = new Message();                msg.obj= contentBuf;                handler_setdate.sendMessage(msg);            } catch (MalformedURLException e) {                e.printStackTrace();            } catch (UnsupportedEncodingException e) {                e.printStackTrace();            } catch (IOException e) {                e.printStackTrace();            }        }    }).start();}