java - AsyncTask 中 CookieSyncManager.createInstance 中的 NullPointerException

Question

我有一个从AysncTask扩展的类。在 doInBackground 方法中我想更新 cookie，所以我有:

CookieSyncManager.createInstance(context);      // <<<<<<<<<<<<<<<<<<
CookieManager cookieManager = CookieManager.getInstance();
cookieManager.setCookie(cookie.getDomain(), cookieString); 
CookieSyncManager.getInstance().sync();

但是我在第一行得到java.lang.NullPointerException。

所以，问题是:

• 为什么会导致这种情况？
• 我是否需要在另一个 Activity 中创建它，然后仅在此 Activity 中使用它？如何 ？为什么？

<小时/>

注释:

• 我知道我的上下文不为空，我已检查过。
• 我无法在 AsyncTask 上使用 onCreate 方法。 To do this.

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这是堆栈跟踪:

  java.lang.NullPointerException
    at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:101)
    at android.webkit.JniUtil.setContext(JniUtil.java:53)
    at android.webkit.CookieSyncManager.createInstance(CookieSyncManager.java:89)
    at com.t.m.library.HttpRequest.doInBackground(HttpRequest.java:129)
    at com.t.m.library.HttpRequest.doInBackground(HttpRequest.java:1)
    at android.os.AsyncTask$2.call(AsyncTask.java:287)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
    at java.util.concurrent.FutureTask.run(FutureTask.java:137)
    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
    at java.lang.Thread.run(Thread.java:856)

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这是我的doInBackground方法:

request = new HttpGet(this.url);
request.addHeader("Accept", "application/json");
request.addHeader("Authorization", this.basicAuthentication);
HttpParams httpParams = new BasicHttpParams();
HttpProtocolParams.setVersion(httpParams, HttpVersion.HTTP_1_1);
HttpClient httpclient = null;
httpclient = new DefaultHttpClient(httpParams);

HttpResponse response = httpclient.execute(request);


// The content from the requested URL along with headers, etc.
HttpEntity entity = response.getEntity();
String responseBody = EntityUtils.toString(entity, "UTF-8");

CookieSyncManager.createInstance(context);
CookieManager cookieManager = CookieManager.getInstance();
cookieManager.setCookie(cookie.getDomain(), cookieString); 
CookieSyncManager.getInstance().sync();

Answer 1

我在 Application 的 onCreate() 中调用它，将应用程序作为上下文传递