从AsyncTask的onPostExecute更新共享preferences [英] update shared preferences from AsyncTask onPostExecute

问题描述

AsyncTask的onPostExecute崩溃（报告nullpointerexecption），当我尝试使用我从doInBackground收到的值更新共享preferences。

AsyncTask onPostExecute crashes (reports nullpointerexecption) when I try to use the value I received from doInBackground to update SharedPreferences.

我的句柄调用活动是：<？code>私人DashboardActivity＆LT;＆GT; callerActivity; 用了＆LT;＆GT; 它抱怨。我已经特里几种方法：1）更新SP在onPostExecute为：

My handle to the calling activity is: private DashboardActivity<?> callerActivity; with out the <?> it complains. I've trie a couple of ways: 1) update SP in onPostExecute as:

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(callerActivity);
prefs.edit().putInt("lastrecord", intRec ).commit();

我也叫了一个callerActivity方法：

I've also called a method in the callerActivity as:

callerActivity.storeLastInsertedRecord(intRec);

所有错误都一样，nullpointerexection这些线路上。

All the errors are the same, nullpointerexection on these lines.

什么可能我是做错了什么？这个答案<一个href=\"http://stackoverflow.com/questions/12604414/android-shared-$p$pferences-set-in-an-asynctask-onpostexecute-not-always-set\">Android ？ - 共享preferences在AsyncTask的onPostExecute（套）并不总是通过设置的@denisdrew是最接近的，但它崩溃在同一个地方，当我尝试实例化意图：

What might I be doing wrong? This answer Android - shared preferences set in an AsyncTask onPostExecute() not always set? by @denisdrew is the closest, but for it crashes at the same place when I try instantiate the intent:

Intent myIntent = new Intent(callerActivity.getApplicationContext(), SharedPrefsHelperActivity.class);

或

Intent myIntent = new Intent(callerActivity.getBaseContext(), SharedPrefsHelperActivity.class);

什么可能被我做错了？我知道，我正在试图把值不为空（intRec）。

what might I be doing wrong? I know that the value that I'm trying to push is not null (intRec).

推荐答案

所以，问题最有可能涉及到分配给上下文的 NULL 。我建议你​​通过的AsyncTask如参见的构造函数传递上下文变量

So problem is most likely related to Context that is assigned to NULL. I suggest you pass Context variable via constructor of AsyncTask e.q

private Context c;

public MyTask(Context c) {
   this.c = c;
}

和调用它：

new MyTask(YourCallerActivity.this).execute();

结果
注意：我最近使用过类似的问题（节省共享preferences在onPostExecute）和一切运行良好，因为我可以通过构造通过上下文

Note: I recently worked on similar issue(saving SharedPreferences in onPostExecute) and everything worked fine since i passed Context via constructor.

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