java - 异步任务空错误

Question

我目前正在处理一个解析 JSON 字符串的异步任务。一旦字符串被解析并且任务从 doInBackground() 移动到 postExecute() 它给了我这个错误:

06-17 20:19:53.612: E/AndroidRuntime(591): FATAL EXCEPTION: main
06-17 20:19:53.612: E/AndroidRuntime(591): java.lang.NumberFormatException: unable to parse 'null' as integer
06-17 20:19:53.612: E/AndroidRuntime(591):  at java.lang.Integer.parseInt(Integer.java:356)
06-17 20:19:53.612: E/AndroidRuntime(591):  at java.lang.Integer.parseInt(Integer.java:332)
06-17 20:19:53.612: E/AndroidRuntime(591):  at stefan.testservice.ParkingActivity$DownloadTask.onPostExecute(ParkingActivity.java:258)
06-17 20:19:53.612: E/AndroidRuntime(591):  at android.os.AsyncTask.finish(AsyncTask.java:417)
06-17 20:19:53.612: E/AndroidRuntime(591):  at android.os.AsyncTask.access$300(AsyncTask.java:127)
06-17 20:19:53.612: E/AndroidRuntime(591):  at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
06-17 20:19:53.612: E/AndroidRuntime(591):  at android.os.Handler.dispatchMessage(Handler.java:99)
06-17 20:19:53.612: E/AndroidRuntime(591):  at android.os.Looper.loop(Looper.java:123)
06-17 20:19:53.612: E/AndroidRuntime(591):  at android.app.ActivityThread.main(ActivityThread.java:3683)
06-17 20:19:53.612: E/AndroidRuntime(591):  at java.lang.reflect.Method.invokeNative(Native Method)
06-17 20:19:53.612: E/AndroidRuntime(591):  at java.lang.reflect.Method.invoke(Method.java:507)
06-17 20:19:53.612: E/AndroidRuntime(591):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
06-17 20:19:53.612: E/AndroidRuntime(591):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
06-17 20:19:53.612: E/AndroidRuntime(591):  at dalvik.system.NativeStart.main(Native Method)

它之前工作得很好，突然之间异步任务结束时的“return null”语句似乎出现了一些问题。我似乎找不到解决办法。提前致谢。

我的代码 fragment :

private class DownloadTask extends AsyncTask<String, Void, Object> {
    @Override
    protected Object doInBackground(String... args) {
        Log.i("MyApp", "Background thread starting");

            Global.url = "http://10.0.2.2:8000/CarServiceScheduling1/resources/json/product/getpark?degree="+degreeStatus+"&year="+yearStatus+"&distance="+distance+"&devid="+Global.android_id;

            try{
                statusCode = cg.connection();    
            }catch (Exception e) {
                test_connection  = true;
            }


            if(test_connection == false){

                try {
                    output = cg.stringconverter(Global.data);
                    cg.parseGson(output);
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

            }
        }
        return null;
    }



protected void onPostExecute(Object result) {

                if (ParkingActivity.this.progressDialog != null) {
                    ParkingActivity.this.progressDialog.dismiss();

                    if(CheckboxPreference == true && Integer.parseInt(Global.preference1) == 0 && Integer.parseInt(Global.preference2) == 0 && (Global.status.equalsIgnoreCase("No Slots available") || Global.status.equalsIgnoreCase("No"))){


                        Intent searchSubActivity = new Intent(getBaseContext(),
                                Nospotsactivity.class);
                        startActivity(searchSubActivity);
                    }
                    else if (CheckboxPreference == true && (Integer.parseInt(Global.preference1) != 0 || Integer.parseInt(Global.preference2) != 0 )){

                        Intent searchSubActivity = new Intent(getBaseContext(),
                                Spotsfoundactivity.class);
                        startActivity(searchSubActivity);
                    }   
                    else if(CheckboxPreference == false && (Integer.parseInt(Global.preference1) != 0 || Integer.parseInt(Global.preference2) != 0 )){


                        Intent searchSubActivity = new Intent(getBaseContext(),
                                Spotsfoundactivity.class);
                        startActivity(searchSubActivity);
                    }
                    if(Integer.parseInt(Global.preference1) == 0 && Integer.parseInt(Global.preference2) == 0){

                        if(Global.status.equalsIgnoreCase("Hardly Likely")){


                            Intent searchSubActivity = new Intent(getBaseContext(),
                                    Unlikelyactivity.class);
                            startActivity(searchSubActivity);
                        }


                        else if(Global.status.equalsIgnoreCase("Likely")){


                            Intent searchSubActivity = new Intent(getBaseContext(),
                                    Likelyactivity.class);
                            startActivity(searchSubActivity);

                        }
                    }
                }
            }   
        }
    }
}

Answer 1

根据您的堆栈跟踪，Global.preference1 或 Global.preference2 为空(或两者)。在将它们解析为整数之前，您可能需要进行空检查。