Question

我需要从我的Android应用程序做一些HTTP请求。我根据需要使用AsyncTask，将网络部分放在doInBackground中。

这是我的请求类：

public class AsyncRequest extends AsyncTask<Void, Integer, HttpResponse>{

private     ProgressDialog  dialog;
private     Activity        activity;
private     HttpUriRequest  query;
private     HttpClient      client;
private     HttpResponse    response;
private     String          dialogMsg;
private     String          uri;

public String getUri() {
    return uri;
}

public void setUri(String uri) {
    this.uri = uri;
}

public AsyncRequest(Activity a, HttpUriRequest q, HttpClient c, String m) {
    query = q;
    client = c;
    activity = a;
    dialog = new ProgressDialog(a);
    dialogMsg = m;
}

@Override
protected void onPostExecute(HttpResponse res) {
    if (dialog.isShowing())
        dialog.dismiss();
}

protected void onPreExecute() {
    this.dialog.setMessage(dialogMsg);
    this.dialog.show();
}

@Override
protected HttpResponse  doInBackground(Void... arg0) {
    try {
        response = client.execute(query);
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }       
    return response;
}

protected   HttpResponse    getResponse() {
    return response;
}
}

而且，在我的UI线程中，我以这种方式使用它：

AsyncRequest        request;
    HttpClient          httpClient = new DefaultHttpClient();
    HttpGet             getQuery = new            HttpGet("Here goes my url");
    HttpResponse        response = null;
    String              rt = "Null";
    getQuery.setHeader("Authorization",    getIntent().getExtras().getString("token"));

    request = new AsyncRequest(this, getQuery, httpClient, "Loading events...");
    try {
        response =  request.execute().get(3, TimeUnit.SECONDS);
    } catch (Exception e) {
        e.printStackTrace();
    }
    HttpEntity entity = response.getEntity();
    try {
        rt = EntityUtils.toString(entity);
    } catch (Exception e) {
             e.printStackTrace();
        return ;
    }

所以，我是一个Android初学者，但我猜这个异常是在主线程中执行网络相关代码时捕获的。但是我在doInBackground（）方法中运行client.execute（）。是调用execute（）。get（）（在ui线程中）导致问题吗？

Answer 1

你有这个

response =  request.execute().get(3, TimeUnit.SECONDS);

调用get()使AsyncTask不再异步。它阻止ui线程等待响应。这会导致NetworkOnMainThreadException。

摆脱get(3, TimeUnit.SECONDS);

只需使用request.execute()即可。您可以在onPostExecute中更新ui。您还可以使用interface作为Activity的回调。

通过以下链接检查黑带的答案

How do I return a boolean from AsyncTask?

使用AsyncTask的NetworkOnMainThreadException

1 个答案: