Android crashing on ListPreference

Question

I'm trying to add a listpreference to my application. My xml code is the following:

  <?xml version="1.0" encoding="utf-8"?>
 <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<PreferenceCategory android:title="@string/calendarsettings">
    <CheckBoxPreference android:key="syncWithCalendar"
        android:title="@string/setting_calendarsync" android:summary="@string/setting_calendarsync"></CheckBoxPreference>
    <CheckBoxPreference android:key="calendarAlarm"
        android:title="@string/settings_calendaralarm" android:summary="@string/settings_calendaralarm"></CheckBoxPreference>
</PreferenceCategory>
<PreferenceCategory android:title="@string/filters">
    <ListPreference android:key="dayFilter" android:title="@string/dayfilter"
        android:summary="@string/dayfilter" android:entries="@array/dayFilterArray"
        android:entryValues="@array/dayFilterValues" />
</PreferenceCategory>
 </PreferenceScreen>

And my array values are:

    <?xml version="1.0" encoding="utf-8"?>
 <resources>
<string-array name="dayFilterArray">
 <item>a</item>
 <item>b</item>
 <item>c</item>
 <item>d</item>
 <item>e</item>
 <item>f</item>
 <item>g</item>
 </string-array>
  <string-array name="dayFilterValues">
 <item>0</item>
 <item>3</item>
 <item>7</item>
 <item>14</item>
 <item>30</item>
 <item>90</item>
 <item>365</item>
  </string-array>
 </resources>

However when I try to enter my preference menu it crashes with the following exception:

10-03 20:27:56.938: ERROR/AndroidRuntime(1111): Caused by: java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String

Which refers to this line of code:

    addPreferencesFromResource(R.xml.preferences);

Any thoughts on this and why is it happening? Thanks.

FULL STACK TRACE:

10-03 21:13:06.828: ERROR/AndroidRuntime(3045): FATAL EXCEPTION: main
10-03 21:13:06.828: ERROR/AndroidRuntime(3045): java.lang.RuntimeException: Unable to start activity ComponentInfo{cPreferencesActivity}: java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1748)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1764)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.app.ActivityThread.access$1500(ActivityThread.java:122)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1002)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.os.Looper.loop(Looper.java:132)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.app.ActivityThread.main(ActivityThread.java:4025)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at java.lang.reflect.Method.invokeNative(Native Method)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at java.lang.reflect.Method.invoke(Method.java:491)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at dalvik.system.NativeStart.main(Native Method)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045): Caused by: java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.app.SharedPreferencesImpl.getString(SharedPreferencesImpl.java:203)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.Preference.getPersistedString(Preference.java:1367)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.ListPreference.onSetInitialValue(ListPreference.java:278)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.Preference.dispatchSetInitialValue(Preference.java:1283)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.Preference.onAttachedToHierarchy(Preference.java:1095)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.PreferenceGroup.addPreference(PreferenceGroup.java:156)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.PreferenceGroup.addItemFromInflater(PreferenceGroup.java:97)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.PreferenceGroup.addItemFromInflater(PreferenceGroup.java:38)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.GenericInflater.rInflate(GenericInflater.java:488)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.GenericInflater.rInflate(GenericInflater.java:493)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.GenericInflater.inflate(GenericInflater.java:326)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.GenericInflater.inflate(GenericInflater.java:263)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.PreferenceManager.inflateFromResource(PreferenceManager.java:269)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.preference.PreferenceActivity.addPreferencesFromResource(PreferenceActivity.java:1333)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at PreferencesActivity.onCreate(PreferencesActivity.java:33)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1048)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1712)
10-03 21:13:06.828: ERROR/AndroidRuntime(3045):     ... 11 more

Answer 1

You have persisted an Integer before in the preferences. ListActivity expects a String so cast fails.

Just call this code at the beginning of onCreate to remove the wrong value and this should be fixed:

PreferenceManager.getDefaultSharedPreferences(this).edit().remove("dayFilter").commit();

If it still happens than you're probably using the dayFilter twice as key for different preferences or do persist that key on your own as Integer somewhere in your code.

If this doesn't work then try to remove your preferences from this locations:

/data/data/YOUR_PACKAGE_NAME/shared_prefs/YOUR_PREFS_NAME.xml
/data/data/YOUR_PACKAGE_NAME/shared_prefs/YOUR_PACKAGE_NAME_preferences.xml

// on some devices
/dbdata/databases/YOUR_PACKAGE_NAME/shared_prefs/YOUR_PREFS_NAME.xml

If this does fail, try to uninstall application so they should be removed (this doesn't work on my Samsung Galaxy S - shared preferences are not deleted...)

Answer 2

Your XML file isn't written correctly, you declare an array of strings but you provide integers hence the Cast exception.

 <string-array name="dayFilterValues">
 <item>0</item>
...
 <item>365</item>
  </string-array>

To fix it simply put quotes around the integer values:

<item>"365"</item>

Then in your app you need to parse the string into an Integer with:

int value = Integer.parseInt(str);