android - Fragment 中 AyncTask 中的 ProgressDialog(崩溃)

Question

我正在尝试在具有 ProgressDialog 的 fragment 中运行 AsyncTask，我已在其他 Activity 中多次执行此操作，但当我在 fragment 中尝试相同操作时，它会因内存泄漏而崩溃。我知道造成这种情况的原因与 ProgressDialog 有关，但我似乎无法弄清楚如何正确执行此操作。

异步任务:

    private void startNewAsyncTask() {
    NetCheck asyncTask = new NetCheck();
    asyncTask.execute();
}

private class NetCheck extends AsyncTask<String, String, Boolean>
{

    private ProgressDialog nDialog;

     protected void onPreExecute(){
      super.onPreExecute();
        nDialog = new ProgressDialog(getActivity());
        nDialog.setTitle("Checking Network");
        nDialog.setMessage("Loading..");
        nDialog.setIndeterminate(false);
        nDialog.setCancelable(true);
        nDialog.show();
}


    protected Boolean doInBackground(String... args){

        ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo ni = cm.getActiveNetworkInfo();
        if (ni != null && ni.isConnected()){
            try {
                URL url = new URL("http://www.google.com"); 
                HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
                urlc.setConnectTimeout(4000);
                urlc.connect();
                if (urlc.getResponseCode() == 200){
                    return true;
                }
            }catch (MalformedURLException e1){
                e1.printStackTrace(); 
            }catch (IOException e){
                e.printStackTrace();
            }

        }

        return false;
    }

    protected void onPostExecute(Boolean th){

        if(th == true){
            nDialog.dismiss();

        }
        else{
            nDialog.dismiss();
            errorMessage.setText("Error connecting to network");
        }
    }

错误日志:

    03-25 10:53:58.074: E/WindowManager(4549): Activity com.gmail.lucsantisf.software_project.views.ProfileView has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@41d2cba8 that was originally added here
03-25 10:53:58.074: E/WindowManager(4549): android.view.WindowLeaked: Activity com.gmail.lucsantisf.software_project.views.ProfileView has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@41d2cba8 that was originally added here
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.ViewRootImpl.<init>(ViewRootImpl.java:418)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:294)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:226)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:151)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.Window$LocalWindowManager.addView(Window.java:547)
03-25 10:53:58.074: E/WindowManager(4549):  at android.app.Dialog.show(Dialog.java:277)
03-25 10:53:58.074: E/WindowManager(4549):  at com.gmail.lucsantisf.software_project.fragments.ProfilePhotosFragment$NetCheck.onPreExecute(ProfilePhotosFragment.java:70)
03-25 10:53:58.074: E/WindowManager(4549):  at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:586)
03-25 10:53:58.074: E/WindowManager(4549):  at android.os.AsyncTask.execute(AsyncTask.java:534)
03-25 10:53:58.074: E/WindowManager(4549):  at com.gmail.lucsantisf.software_project.fragments.ProfilePhotosFragment.startNewAsyncTask(ProfilePhotosFragment.java:55)
03-25 10:53:58.074: E/WindowManager(4549):  at com.gmail.lucsantisf.software_project.fragments.ProfilePhotosFragment.onCreateView(ProfilePhotosFragment.java:49)
03-25 10:53:58.074: E/WindowManager(4549):  at android.support.v4.app.Fragment.performCreateView(Fragment.java:1500)
03-25 10:53:58.074: E/WindowManager(4549):  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:927)
03-25 10:53:58.074: E/WindowManager(4549):  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
03-25 10:53:58.074: E/WindowManager(4549):  at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
03-25 10:53:58.074: E/WindowManager(4549):  at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
03-25 10:53:58.074: E/WindowManager(4549):  at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:472)
03-25 10:53:58.074: E/WindowManager(4549):  at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
03-25 10:53:58.074: E/WindowManager(4549):  at android.support.v4.view.ViewPager.populate(ViewPager.java:1068)
03-25 10:53:58.074: E/WindowManager(4549):  at android.support.v4.view.ViewPager.populate(ViewPager.java:914)
03-25 10:53:58.074: E/WindowManager(4549):  at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1436)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.View.measure(View.java:15264)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4916)
03-25 10:53:58.074: E/WindowManager(4549):  at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1390)
03-25 10:53:58.074: E/WindowManager(4549):  at android.widget.LinearLayout.measureVertical(LinearLayout.java:681)
03-25 10:53:58.074: E/WindowManager(4549):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:574)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.View.measure(View.java:15264)
03-25 10:53:58.074: E/WindowManager(4549):  at android.widget.ScrollView.measureChildWithMargins(ScrollView.java:1196)
03-25 10:53:58.074: E/WindowManager(4549):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
03-25 10:53:58.074: E/WindowManager(4549):  at android.widget.ScrollView.onMeasure(ScrollView.java:318)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.View.measure(View.java:15264)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4916)
03-25 10:53:58.074: E/WindowManager(4549):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.View.measure(View.java:15264)
03-25 10:53:58.074: E/WindowManager(4549):  at android.widget.LinearLayout.measureVertical(LinearLayout.java:833)
03-25 10:53:58.074: E/WindowManager(4549):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:574)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.View.measure(View.java:15264)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4916)
03-25 10:53:58.074: E/WindowManager(4549):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
03-25 10:53:58.074: E/WindowManager(4549):  at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2339)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.View.measure(View.java:15264)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2131)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1242)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1435)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1127)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4606)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.Choreographer$CallbackRecord.run(Choreographer.java:747)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.Choreographer.doCallbacks(Choreographer.java:567)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.Choreographer.doFrame(Choreographer.java:536)
03-25 10:53:58.074: E/WindowManager(4549):  at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:733)
03-25 10:53:58.074: E/WindowManager(4549):  at android.os.Handler.handleCallback(Handler.java:615)
03-25 10:53:58.074: E/WindowManager(4549):  at android.os

有人知道我做错了什么吗？

感谢您的帮助!

Answer 1

您正在调用 fragment 的 onCreateView() 中的 show() 方法。该 fragment 尚未通过其 onResume() 回调，因此它没有可供进度对话框使用的有效窗口，因此这种不匹配会导致泄漏。将 AsyncTask 的开头移动到 fragment 的 onResume() 方法中，这应该可以解决问题。