PreferenceScreen - - Exception - FLAG_ACTIVITY_NEW_TASK

问题

I am new at android developing.

The project is about implementing an AbstractAccountAuthenticator with an AbstractThreadedSyncAdapter to sync certain data on a server with a content provider.

I made everything and both adding accounts and syncing is running without any problems.

Now I've tried to add a Preference-Screen just like suggested in the android reference (search for AbstractAccountAuthenticator, it is explained there) via xml like this:

autenticator.xml:

<account-authenticator xmlns:android="http://schemas.android.com/apk/res/android"
    android:accountType="typeOfAuthenticator"
    android:icon="@drawable/icon"
    android:smallIcon="@drawable/miniIcon"
    android:label="@string/label"
    android:accountPreferences="@xml/account_preferences"
 />

The Preference-Screen-xml looks like this:

account_preferences.xml:

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
 <PreferenceCategory android:title="@string/pref_cat_general">
  <PreferenceScreen android:key="@string/pref_cat_scr_keygen" android:title="@string/pref_cat_scr_keygen_title" android:summary="@string/pref_cat_scr_keygen_summary">
   <intent android:action="android.intent.action.VIEW" android:targetPackage="com.android.clean" android:targetClass="com.android.clean.KeygenAct" />
  </PreferenceScreen>
 </PreferenceCategory>
</PreferenceScreen>

The screen is promted how it should be, but and that is the problem: When I click on the PreferenceScreen with the intent it leads to a crash of the system (both in the emulator and my HTC-Desire).

Logcat says:

ERROR/AndroidRuntime(18754): android.util.AndroidRuntimeException: Calling startActivity() from outside of an Activity context requires the FLAG_ACTIVITY_NEW_TASK flag. Is this really what you want?

(whole Logcat on pastebin)

Here the part of the manifest, where the activity is defined:

<activity android:name=".KeygenAct">
    <intent-filter>
     <action android:name="android.intent.action.VIEW" />
     <category android:name="android.intent.category.DEFAULT" />
    </intent-filter>
</activity>

The whole test-code (it is my project on the essentials to find the problem) is to find at googlecode (http://code.google.com/p/cleanproject/source/browse/) (Eclipse-Project)

Thank you already for your help, Esentian

p.s.: keygen is not a key generator, it means more key_general. A bit inartfully expressed ;)

回答1:

i had the same problem and have just found out, that if you change your preferences to:

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
 <PreferenceCategory android:title="@string/pref_cat_general">
 </PreferenceCategory>
  <PreferenceScreen android:key="@string/pref_cat_scr_keygen" android:title="@string/pref_cat_scr_keygen_title" android:summary="@string/pref_cat_scr_keygen_summary">
   <intent android:action="android.intent.action.VIEW" android:targetPackage="com.android.clean" android:targetClass="com.android.clean.KeygenAct" />
  </PreferenceScreen>
</PreferenceScreen>

Then it works as expected. This is weird because I would expect PreferenceCategory to group items as its children... And why does it result with such unrelated (?) error?

来源：https://stackoverflow.com/questions/3727249/preferencescreen-intent-exception-flag-activity-new-task

标签

android