重新打开活动时出现AsyncTask（doInBackground方法）问题

时间：2011-06-20 09:53:00

标签： android android-asynctask

最近我开始使用AsyncTask，我发现使用它时遇到了一些问题。

我有这个ListActivity（CatalogActivity），我使用AsyncTask重新加载它，因为它是某种树逻辑。每次我在列表中选择一个项目时，我会在doInBackground方法中进行一些计算并显示进度对话框，而在onPostExecute中我会重新加载列表并忽略进度。一切正常。

完成后（我到达最后一级）我开始另一个活动（LoginActivity）。这个新活动有“后退”菜单按钮，可以启动我之前提到的列表活动。它启动了活动，当我在doInBackground方法中点击加载部分时，我得到了这个时髦的例外。真正有趣的部分是，如果我在我的加载方法上设置断点并跨步所有工作正常！

我错过了什么？

以下是我的CatalogActivity的doInBackground方法（错误发生的地方）：

    protected String doInBackground(String... params) {
        catalogAdapter.mappingServicesCatalog.loadFromRml(new RIoConnectionManagerImpl(currentActivity.getApplicationContext()), params[0], null, 120000, 500000);
        if (catalogAdapter.urlMapping.size() == 0)
        {
            catalogAdapter.urlMapping.add(params[0]);
        }
        else
        {
            if (catalogAdapter.urlMapping.get(catalogAdapter.urlMapping.size() - 1) != params[0])
            {
                catalogAdapter.urlMapping.add(params[0]);
            }
        }
        return "";
    }

以下是LogCat记录：

06-20 11:38:21.109: ERROR/AndroidRuntime(22789): FATAL EXCEPTION: AsyncTask #4
06-20 11:38:21.109: ERROR/AndroidRuntime(22789): java.lang.RuntimeException: An error occured while executing doInBackground()
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at android.os.AsyncTask$3.done(AsyncTask.java:200)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at java.util.concurrent.FutureTask.run(FutureTask.java:137)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at java.lang.Thread.run(Thread.java:1096)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789): Caused by: java.lang.NullPointerException
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at si.realis.rmap.android.CatalogActivity$CatalogAdapter.access$1(CatalogActivity.java:35)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at si.realis.rmap.android.CatalogActivity$LoadRMLCatalog.doInBackground(CatalogActivity.java:197)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at si.realis.rmap.android.CatalogActivity$LoadRMLCatalog.doInBackground(CatalogActivity.java:1)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at android.os.AsyncTask$2.call(AsyncTask.java:185)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
06-20 11:38:21.109: ERROR/AndroidRuntime(22789):     ... 4 more
06-20 11:38:44.086: ERROR/WindowManager(22789): Activity si.realis.rmap.android.CatalogActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@47f532a0 that was originally added here
06-20 11:38:44.086: ERROR/WindowManager(22789): android.view.WindowLeaked: Activity si.realis.rmap.android.CatalogActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@47f532a0 that was originally added here
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.view.ViewRoot.<init>(ViewRoot.java:247)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.view.Window$LocalWindowManager.addView(Window.java:424)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.app.Dialog.show(Dialog.java:241)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.app.ProgressDialog.show(ProgressDialog.java:107)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.app.ProgressDialog.show(ProgressDialog.java:90)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at si.realis.rmap.android.CatalogActivity.loadRMLCatalog(CatalogActivity.java:135)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at si.realis.rmap.android.CatalogActivity$CatalogAdapter.Initialize(CatalogActivity.java:60)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at si.realis.rmap.android.CatalogActivity$CatalogAdapter.<init>(CatalogActivity.java:45)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at si.realis.rmap.android.CatalogActivity.onCreate(CatalogActivity.java:119)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.os.Handler.dispatchMessage(Handler.java:99)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.os.Looper.loop(Looper.java:123)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at android.app.ActivityThread.main(ActivityThread.java:4627)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at java.lang.reflect.Method.invokeNative(Native Method)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at java.lang.reflect.Method.invoke(Method.java:521)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:871)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:629)
06-20 11:38:44.086: ERROR/WindowManager(22789):     at dalvik.system.NativeStart.main(Native Method)
06-20 11:49:00.402: ERROR/WifiManager(22835): showApDialog
06-20 11:49:04.699: ERROR/HierarchicalStateMachine(2475): TetherMaster - unhandledMessage: msg.what=3
06-20 11:49:07.511: ERROR/WifiManager(22835): showApDialog
06-20 11:49:14.648: ERROR/WifiManager(22835): showApDialog
06-20 11:49:23.109: ERROR/libnetutils(2475): dhcp start cmd 11 : [dhcpcd:-ABK] 
06-20 11:49:23.597: ERROR/HierarchicalStateMachine(2475): TetherMaster - unhandledMessage: msg.what=3
06-20 11:49:23.965: ERROR/gps_BRCM(2475): BrcmLbs_sync() return error.

1 个答案:

答案 0 :(得分：0)

我通过修复我的代码（草率工作）来解决这个问题

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