Question

我在MySql中插入数据，数据插入成功。但是在成功操作后我无法Intent到Activity。{ 这是我的代码：

public void registerfinish(View view) {
    ...
    new finalRegister().execute();
}

class finalRegister extends AsyncTask<String, String, String> {

    /**
     * Before starting background thread Show Progress Dialog
     * */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        ...
    }

    /**
     * getting All products from url
     * */
    protected String doInBackground(String... args) {

        List<NameValuePair> params = new ArrayList<NameValuePair>();
        ...
        // getting JSON Object
        // Note that create product url accepts POST method
        JSONObject json = null ;

        try {
            json = jsonParser.makeHttpRequest(url,
                    "GET", params);
        } catch (JSONException e) {
            e.printStackTrace();
        }



        // check for success tag

        try {
            // check log cat fro response
            Log.d("Create Response", json.toString());
            success = json.getInt(TAG_SUCCESS);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        if (success == 1) {
                // successfully created product
                Intent i = new Intent(Register2ndStep.this, FinalScreen.class);
                startActivity(i);

                // closing this screen
                //finish();
            } else {
                ...
            }
        return null;
    }
    protected void onPostExecute(String file_url) {
        // dismiss the dialog after getting all products
        pDialog.dismiss();
        }
    }

}

logcat的：

Caused by: java.lang.NullPointerException
        at wolverine.example.com.btp_scientist.Register2ndStep$finalRegister.doInBackground(Register2ndStep.java:220)
        at wolverine.example.com.btp_scientist.Register2ndStep$finalRegister.doInBackground(Register2ndStep.java:173)

Register2ndStep.java:220:  Log.d("Create Response", json.toString())
Register2ndStep.java:173:   class finalRegister extends AsyncTask<String, String, String>

Answer 1

只需将您的意图代码移动到onPostExecute方法：

 protected void onPostExecute(String file_url) {
         Intent i = new Intent(Register2ndStep.this, FinalScreen.class);
         startActivity(i);
         pDialog.dismiss();
   }

将数据插入mysql后无法实现

1 个答案: