Question

我需要一些帮助！在我的asyncTask中，我正在向ArrayList Result添加值，当我尝试通过

获取onPostExecute中的结果值时

final String output = result.get(0);

该应用程序正在关闭。我知道这可能是一个愚蠢的错误。但我不明白为什么！

public class deviceVerify extends AsyncTask<ArrayList<String>, Void, ArrayList<String>> {
        protected void onPreExecute(){
            progress1.setVisibility(View.VISIBLE);
        }
        @Override
        protected ArrayList<String> doInBackground(ArrayList<String>... passing) {
            // Locate the WorldhavingDelay Class
            // JSON file URL address
            final ArrayList<String> result = new ArrayList<String>();
            String android_id = Settings.Secure.getString(getContentResolver(),
                    Settings.Secure.ANDROID_ID);
            try {
                Log.e("URL",Constants.BASE_URL_LOGIN+"?deviceid="+android_id);
                RestClientHelper.getInstance().get(Constants.BASE_URL_LOGIN+"?deviceid="+android_id, new RestClientHelper.RestClientListener() {
                    @Override
                    public void onSuccess(String response) {
                        Log.e("Resposnse",response);
                        result.add("true");
                    }

                    @Override
                    public void onError(String error) {
                        Log.e("Error",error);
                        result.add("false");
                    }
                });
            } catch (Exception e) {
                result.add("false");
            }
            return result;
        }
        protected void onPostExecute(final ArrayList<String> result) {
            final String output = result.get(0);
            final Handler handler = new Handler();
            handler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    progress1.setVisibility(View.INVISIBLE);
                    if(output.equals("true")){
                        TextView verifytext = (TextView) findViewById(R.id.verifytext);
                        verifytext.setText("Device Verified");
                        ImageView error = (ImageView) findViewById(R.id.messageImage);
                        error.setImageResource(DeviceVerification.this.getResources().getIdentifier("check", "drawable", DeviceVerification.this.getPackageName()));
                    }
                    else{
                        TextView verifytext = (TextView) findViewById(R.id.verifytext);
                        verifytext.setText("An Error Occured on verifying device!");
                        ImageView error = (ImageView) findViewById(R.id.messageImage);
                        error.setImageResource(DeviceVerification.this.getResources().getIdentifier("warning", "drawable", DeviceVerification.this.getPackageName()));
                        Button tryagain = (Button) findViewById(R.id.trygain);
                        tryagain.setVisibility(View.VISIBLE);
                    }

                }
            }, 10000);
        }

LOG ERROR：

02-22 15:06:34.708 10664-10664/in.juasoft.mobeeload E/AndroidRuntime: FATAL EXCEPTION: main
                                                                      Process: in.juasoft.mobeeload, PID: 10664
                                                                      java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
                                                                          at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
                                                                          at java.util.ArrayList.get(ArrayList.java:308)
                                                                          at in.juasoft.mobeeload.DeviceVerification$deviceVerify.onPostExecute(DeviceVerification.java:110)
                                                                          at in.juasoft.mobeeload.DeviceVerification$deviceVerify.onPostExecute(DeviceVerification.java:78)
                                                                          at android.os.AsyncTask.finish(AsyncTask.java:632)
                                                                          at android.os.AsyncTask.access$600(AsyncTask.java:177)
                                                                          at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
                                                                          at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                          at android.os.Looper.loop(Looper.java:136)
                                                                          at android.app.ActivityThread.main(ActivityThread.java:5037)
                                                                          at java.lang.reflect.Method.invokeNative(Native Method)
                                                                          at java.lang.reflect.Method.invoke(Method.java:515)
                                                                          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
                                                                          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
                                                                          at dalvik.system.NativeStart.main(Native Method)

Answer 1

更改

ArrayList<String> result = new ArrayList<String>;
//remove final from result

也改变它不要求，但仅限于标准编码

if(result != null && result.size()>0){   
      final String output = result.get(0);
    }

改变onpost方法你得到这个错误，因为你得到的结果大小为零

Answer 2

您正在“onSuccess”方法上添加ArrayList “result”中的数据，这是回调方法..但是在onSuccess执行之前，onPostExcecute方法会在此时调用，然后调用ArrayList “result “是空的，这就是为什么IndexOutOfBoundExeption ouckured。

Answer 3

我认为您尝试在result.add("true");和result.add("false");

修改最终变量

错误是asynctask onPostExecute

3 个答案: