Question

我遇到此活动的问题。

    package com.ilocal.diary;
import java.util.ArrayList;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;

public class ViewDiary extends Activity {

    private String userid = "1";
    private String response;
    private String url;
    private Bundle bundle = new Bundle();
    private ArrayList<NameValuePair> postParameters;
    private ProgressDialog dialog = null;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.empty_layout);

        this.dialog = ProgressDialog.show(this, "Working..", "Downloading Data...", true, false);

        bundle = this.getIntent().getExtras();
        if (bundle != null) {
            userid = bundle.getString("USERID");
        }
        url ="http://www.ilocaltest.x10.mx/android/fetchdiary.php";
        postParameters = new ArrayList<NameValuePair>();
        postParameters.add(new BasicNameValuePair("userid", userid));

        new PHPQuery().execute(url, postParameters);
    }

    private class PHPQuery extends AsyncTask<Object, Void, String > {
        protected String doInBackground(Object... params) {
            try {
                response = CustomHttpClient.executeHttpPost(url, postParameters);
            } catch (Exception e) {
                System.out.println("HTTP error - " + e.toString());
            }
            System.out.println(response);
            return response;
        }

        protected void onPostExecute(String result) {
            dialog.dismiss();
            System.out.println(result);
            if (!(result == null)) {
                bundle.putString("RESPONSE", result);
                Intent i = new Intent(ViewDiary.this, DisplayDiary.class);
                i.putExtras(bundle);
                startActivity(i);
                ViewDiary.this.finish();
            }
            else
                finish();
        }
    }
}

当我在行中获得nullpointerexecption时尝试捆绑AsyncTask的结果时，一切正常工作

bundle.putString("RESPONSE", result);

我知道结果已经传递给了onPostExecute方法，所以异常来自哪里以及如何修复它。

马丁

Answer 1

您实例化了bundle，但是如果意图是在没有bundle的情况下触发的话，那么你将this.getIntent().getExtras();分配给null，这可能就是这种情况。在放入bundle之前检查null，如果为null，则实例化它。

更好的是，检查getExtras()之后是否为null，如果是，则实例化：

bundle = this.getIntent().getExtras();
if (bundle == null)
    bundle = new Bundle();
else {//...

AsyncTask之后的bundle中的NullPointerException

1 个答案: