Question

我在我的Android应用程序中有一个活动，我在按钮点击时将数据发送到服务器。但是当我点击按钮时，我得到了java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()我在谷歌上搜索但没有得到解决方案。以下是我的代码：

try
    {
    HttpAsyncRegUser httpasync = new HttpAsyncRegUser();
    urlforpurchase = "http://"+ Constants.ip +"/venuscmsapp/services/purchase/insertpurchasedetails";
    Toast.makeText(getApplicationContext(), "1", Toast.LENGTH_LONG).show();
    httpasync.execute(new String[] { urlforpurchase });
    }
     catch(Exception excp){
        Log.e("Error fetching data : ", excp.getMessage());
    }

    Toast.makeText(getApplicationContext(), "hii", Toast.LENGTH_LONG).show();
    }

    private class HttpAsyncRegUser extends AsyncTask<String, Void, String> {

        @Override
        protected void onPostExecute(String result) {
            // TODO Auto-generated method stub

                Toast.makeText(getApplicationContext(), "Post", Toast.LENGTH_LONG).show();

            super.onPostExecute(result);
        }

        @Override
        protected String doInBackground(String... params) {
            String str = null;
            try {
                //Toast.makeText(getApplicationContext(), "in HttpAsyncRegUser", Toast.LENGTH_LONG).show();
                HttpClient httpclient = new DefaultHttpClient();
                String json;
                HttpPost httpPost = new HttpPost(urlforpurchase);
                 JSONObject puchaseJson = new JSONObject();

                 puchaseJson.put("productId", ITEM_SKU);
                 puchaseJson.put("userId", userId);
                 puchaseJson.put("productprice", price);
                 puchaseJson.put("productStartDate", productStartDate);
                 puchaseJson.put("productEndDate", productEndDate);
                 puchaseJson.put("paymentStatus",1);
                 puchaseJson.put("paymentDate", paymentDate);
                 puchaseJson.put("productType","SONG");
                 puchaseJson.put("status",1);

                 json = puchaseJson.toString();
                 System.out.println(">>>>>>>>>>>>>>>>>>>>>>>>>  "+json);
                 StringEntity se = new StringEntity(json);
                 System.out.println("=========================  "+se);
                 Toast.makeText(getApplicationContext(), "in application/json", Toast.LENGTH_LONG).show();
                 Log.e("post", "in application/json");
                 httpPost.setEntity(se);

                 httpPost.setHeader("Accept","application/json");
                 httpPost.setHeader("Content-Type", "application/json");
                 Toast.makeText(getApplicationContext(), "in application/json", Toast.LENGTH_LONG).show();
                 HttpResponse httpResponse = httpclient.execute(httpPost);
                 Toast.makeText(getApplicationContext(), "in httpResponse", Toast.LENGTH_LONG).show();
                 str = inputStreamToString(httpResponse.getEntity().getContent()).toString();
                 Toast.makeText(getApplicationContext(), "in last", Toast.LENGTH_LONG).show();
            } catch (Exception e) {
                e.printStackTrace();
                //Toast.makeText(getApplicationContext(), ""+e, Toast.LENGTH_LONG).show();
                Log.e(" my Error", ""+e);
            }
            return str;
        }
        private StringBuilder inputStreamToString(InputStream is) {

            String line = "";
            StringBuilder total = new StringBuilder();

            BufferedReader rd = new BufferedReader(new InputStreamReader(is));

            try {
                while ((line = rd.readLine()) != null) {
                    total.append(line);
                }

            } catch (Exception e) {
                e.printStackTrace();
            }
            return total;

        }
    }

以下是我的logcat输出：

09-18 12:03:40.851: W/System.err(1742): java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
09-18 12:03:40.851: W/System.err(1742):     at android.os.Handler.<init>(Handler.java:121)
09-18 12:03:40.851: W/System.err(1742):     at android.widget.Toast.<init>(Toast.java:68)
09-18 12:03:40.851: W/System.err(1742):     at android.widget.Toast.makeText(Toast.java:231)
09-18 12:03:40.851: W/System.err(1742):     at com.venus.browse.BrowseSongListActivity$HttpAsyncRegUser.doInBackground(BrowseSongListActivity.java:1005)
09-18 12:03:40.851: W/System.err(1742):     at com.venus.browse.BrowseSongListActivity$HttpAsyncRegUser.doInBackground(BrowseSongListActivity.java:1)
09-18 12:03:40.851: W/System.err(1742):     at android.os.AsyncTask$2.call(AsyncTask.java:185)
09-18 12:03:40.851: W/System.err(1742):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
09-18 12:03:40.861: W/System.err(1742):     at java.util.concurrent.FutureTask.run(FutureTask.java:137)
09-18 12:03:40.861: W/System.err(1742):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
09-18 12:03:40.861: W/System.err(1742):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
09-18 12:03:40.861: W/System.err(1742):     at java.lang.Thread.run(Thread.java:1096)
09-18 12:03:40.861: E/my Error(1742): java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()

Answer 1

Toast消息显示在UI上，因此要从线程中显示它，我们必须将其放入UIThread。

替换Toast功能内的每条doInBackground条消息，如下所示

runOnUiThread(new Runnable() {

        @Override
        public void run() {
            Toast.makeText(getApplicationContext(), "in application/json", Toast.LENGTH_LONG).show();
        }
    });

Answer 2

您无法在Toast的{{1}}方法中使用doInBackground()。 Toast实际上与UI交互，AsyncTask方法在后台运行（后台线程），并且不会影响UI。

这就是您收到此错误的原因。 doInBackground()

Answer 3

只需从doInBackground()方法

中删除此行即可

 Toast.makeText(getApplicationContext(), "in application/json", Toast.LENGTH_LONG).show();
 Toast.makeText(getApplicationContext(), "in httpResponse", Toast.LENGTH_LONG).show();
 Toast.makeText(getApplicationContext(), "in last", Toast.LENGTH_LONG).show();

您无法使用该方法更新您的用户界面。

在doInBackground()中，您只能执行后台处理和网络操作。

无法使用线程内部处理程序的RuntimeException将数据发送到服务器

3 个答案: