java – 为什么这个后台任务因致命异常而失败?
发布时间:2020-12-15 04:19:05 所属栏目:Java 来源:网络整理
导读:我的MainActivity中的以下代码在重写的doInBackground()方法中失败并出现致命异常: public class MainActivity extends ActionBarActivity { . . . public void onFetchBtnClicked(View v){ if(v.getId() == R.id.FetchBtn){ Toast.makeText(getApplication
我的MainActivity中的以下代码在重写的doInBackground()方法中失败并出现致命异常:
public class MainActivity extends ActionBarActivity { . . . public void onFetchBtnClicked(View v){ if(v.getId() == R.id.FetchBtn){ Toast.makeText(getApplicationContext(),"You mashed the button,dude.",Toast.LENGTH_SHORT).show(); new NetworkTask().execute(); } } public static class NetworkTask extends AsyncTask<String,Void,HttpResponse> { @Override protected HttpResponse doInBackground(String... params) { String link = params[0]; HttpGet request = new HttpGet("http://localhost:28642/api/deliveries/Count"); AndroidHttpClient client = AndroidHttpClient.newInstance("Android"); try { return client.execute(request); } catch (IOException e) { e.printStackTrace(); return null; } finally { client.close(); } } @Override protected void onPostExecute(HttpResponse result) { FileOutputStream f = null; //Do something with result if (result != null) /* result.getEntity().writeTo(new FileOutputStream(f)); */ try { result.getEntity().writeTo(f); } catch (IOException e) { e.printStackTrace(); } } } 具有异常上下文的smidgin的特定异常消息如下: 03-31 18:04:26.350 1401-1401/hhs.app I/Choreographer﹕ Skipped 33 frames! The application may be doing too much work on its main thread. 03-31 18:05:00.030 1401-1420/hhs.app W/dalvikvm﹕ threadid=12: thread exiting with uncaught exception (group=0xb2a7aba8) 03-31 18:05:00.250 1401-1420/hhs.app E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1 Process: hhs.app,PID: 1401 java.lang.RuntimeException: An error occured while executing doInBackground() at android.os.AsyncTask$3.done(AsyncTask.java:300) at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355) at java.util.concurrent.FutureTask.setException(FutureTask.java:222) at java.util.concurrent.FutureTask.run(FutureTask.java:242) at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) at java.lang.Thread.run(Thread.java:841) Caused by: java.lang.ArrayIndexOutOfBoundsException: length=0; index=0 at hhs.app.MainActivity$NetworkTask.doInBackground(MainActivity.java:68) at hhs.app.MainActivity$NetworkTask.doInBackground(MainActivity.java:64) at android.os.AsyncTask$2.call(AsyncTask.java:288) at java.util.concurrent.FutureTask.run(FutureTask.java:237) ????????????at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) ????????????at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) ????????????at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) ????????????at java.lang.Thread.run(Thread.java:841) 有什么问题 – 它在doInBackground()的git-go失败了.我的网址是由于打击造成的“坏”(在C#中,我会使用逐字字符串),还是……? UPDATE 我删除了有问题的行,但它仍然失败,抛出IOException. 我实际上切换到了完全不同的代码,这里可以看到[为什么我得到,“不兼容的类型:对象无法转换为字符串”这个? (它正在抛出NetworkOnMainThreadException),但是当失败时我决定再给这个代码一个机会,但是输入了“catch(IOException e)”块. 有人知道为什么吗? 解决方法
这个例外:
Caused by: java.lang.ArrayIndexOutOfBoundsException: length=0; index=0 告诉您正在访问索引0处的空数组,在此行中: protected HttpResponse doInBackground(String... params) { String link = params[0]; 注意,在任务之后你不要在任何地方使用链接变量(也不是params). (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |