Question

您好我在我的活动中运行Asynctask并从服务器获取数据。在onPostExecute metod我现在在数据库中插入数据我想在两个不同的片段中传递这些ID我通过以下代码传递id：

Bundle bundle = new Bundle();
    bundle.putStringArray(BConstant.TAXONOMY_TID, dbtids);
    bundle.putStringArray(BConstant.PRODUCT_CATEGORY_NAMES,
            dblistProCategory);
    ProductCategoryFragment.newInstance(bundle);

    // ProductDetailsFragment
    Bundle bundleForProductList = new Bundle();
    bundleForProductList
            .putStringArray(BConstant.TAXONOMY_TID, dbtids);
    bundleForProductList.putString(BConstant.WEB_SERVICES_COOKIES,
            cookie);
    bundleForProductList.putStringArray(
            BConstant.PRODUCT_CATEGORY_NAMES, dblistProCategory);
    ProductListFragment.newInstance(bundleForProductList);

但是上面的代码行在AsyncTask完成之前执行。但是我已在此代码上面写了这一行new CategoryFrag().execute();。我该怎么办。

被修改

protected void onPostExecute(JSONArray result) {
        listItems = new ArrayList<String>();
        for (int i = 0; i < result.length(); i++) {
            try {
                listItems
                        .add(result.getJSONObject(i)
                                .getString(BConstant.NAME_CONSTANT)
                                .toString());
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }
        listProCategory = listItems.toArray(new String[0]);
  returnsTID = saDatabaseHandler.getProductCategoryTID();
        for (int i = 0; i < tids.length; i++) {
            if (!returnsTID.contains(tids[i])) {
                saDatabaseHandler.insertProductCategoryData(
                        tids[i], listProCategory[i]);

            }
        }
        getOfflineData();
  }

logcat的：

    02-02 11:41:00.451: E/AndroidRuntime(20901): FATAL EXCEPTION: main
    02-02 11:41:00.451: E/AndroidRuntime(20901): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.abc.xyz/com.abc.xyz.ProductListActivity}: java.lang.NullPointerException
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2114)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2139)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.app.ActivityThread.access$700(ActivityThread.java:143)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1241)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.os.Handler.dispatchMessage(Handler.java:99)
    02-02 11 :41:00.451: E/AndroidRuntime(20901):   at android.os.Looper.loop(Looper.java:137)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.app.ActivityThread.main(ActivityThread.java:4960)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at java.lang.reflect.Method.invokeNative(Native Method)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at java.lang.reflect.Method.invoke(Method.java:511)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at dalvik.system.NativeStart.main(Native Method)
    02-02 11:41:00.451: E/AndroidRuntime(20901): Caused by: java.lang.NullPointerException
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at java.util.Arrays$ArrayList.<init>(Arrays.java:38)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at java.util.Arrays.asList(Arrays.java:154)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.widget.ArrayAdapter.<init>(ArrayAdapter.java:141)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at com.abc.xyz.ProductCategoryFragment$DisplayProductCategoryListArrayAdapter.<init>(ProductCategoryFragment.java:175)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at com.abc.xyz.ProductCategoryFragment.onActivityCreated(ProductCategoryFragment.java:113)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:848)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1035)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1017)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:1804)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.app.Activity.performCreate(Activity.java:5206)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2078)
    02-02 11:41:00.451: E/AndroidRuntime(20901):    ... 11 more

Answer 1

使用onPostExecute方法调用活动中定义的方法。并在该方法中编写上述代码。

如果异步任务在另一个类中，则从异步任务传递上下文，并在从数据库获取数据后的onPostExecute方法中执行此操作：

((YourCallingActivity)mContext).methodName();

在完成Android任务之前获取执行

被修改

1 个答案: