ClassCastException异常在preferenceActivity [英] ClassCastException in PreferenceActivity
本文介绍了ClassCastException异常在preferenceActivity的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我试图得到一个例子从Android 2应用程序开发书雷托•迈耶工作（202页）。按照说明我已经创建了一个用户preferences.xml如下：
I am trying to get an example from the Android 2 Application Development book by Reto Meier to work (page 202). As per the instructions I have created a userpreferences.xml as follows:
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >
<CheckBoxPreference
android:key="PREF_AUTO_UPDATE"
android:title="Auto refresh"
android:summary="Select to turn on automatic updating"
android:defaultValue="true"
/>
<ListPreference
android:key="PREF_UPDATE_FREQ"
android:title="Refresh frequency"
android:summary="Frequency at which to refresh earthquake list"
android:entries="@array/update_freq_options"
android:entryValues="@array/update_freq_values"
android:dialogTitle="Refresh frequency"
android:defaultValue="60"
/>
<ListPreference
android:key="PREF_MIN_MAG"
android:title="Minimum magnitude"
android:summary="Select the minimum magnitude earthquake to report"
android:entries="@array/magnitude_options"
android:entryValues="@array/magnitude"
android:dialogTitle="Magnitude"
android:defaultValue="3"
/>
</PreferenceScreen>
我的preferences类看起来是这样的...
My Preferences class looks like this...
public class Preferences extends PreferenceActivity {
SharedPreferences prefs;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.userpreferences);
}
我不断收到一个ClassCastException：java.lang.ClassCastException：java.lang.Integer中
12-16 09:28:14.349: ERROR/AndroidRuntime(287): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.dt.sample/com.dt.sample.Preferences}: java.lang.ClassCastException: java.lang.Integer
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.os.Handler.dispatchMessage(Handler.java:99)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.os.Looper.loop(Looper.java:123)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.app.ActivityThread.main(ActivityThread.java:4627)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at java.lang.reflect.Method.invokeNative(Native Method)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at java.lang.reflect.Method.invoke(Method.java:521)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at dalvik.system.NativeStart.main(Native Method)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): Caused by: java.lang.ClassCastException: java.lang.Integer
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.app.ContextImpl$SharedPreferencesImpl.getString(ContextImpl.java:2699)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.preference.Preference.getPersistedString(Preference.java:1249)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.preference.ListPreference.onSetInitialValue(ListPreference.java:232)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.preference.Preference.dispatchSetInitialValue(Preference.java:1172)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.preference.Preference.onAttachedToHierarchy(Preference.java:984)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.preference.PreferenceGroup.addPreference(PreferenceGroup.java:156)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.preference.PreferenceGroup.addItemFromInflater(PreferenceGroup.java:97)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.preference.PreferenceGroup.addItemFromInflater(PreferenceGroup.java:38)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.preference.GenericInflater.rInflate(GenericInflater.java:488)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.preference.GenericInflater.inflate(GenericInflater.java:326)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.preference.GenericInflater.inflate(GenericInflater.java:263)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.preference.PreferenceManager.inflateFromResource(PreferenceManager.java:251)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.preference.PreferenceActivity.addPreferencesFromResource(PreferenceActivity.java:262)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at com.dt.sample.Preferences.onCreate(Preferences.java:24)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
12-16 09:28:14.349: ERROR/AndroidRuntime(287): ... 11 more
在arrays.xml看起来是这样的...
The arrays.xml looks like this...
<resources>
<string-array name="update_freq_options">
<item>Every Minute</item>
<item>5 minutes</item>
<item>10 minutes</item>
<item>15 minutes</item>
<item>Every Hour</item>
</string-array>
<array name="magnitude">
<item>3</item>
<item>5</item>
<item>6</item>
<item>7</item>
<item>8</item>
</array>
<string-array name="magnitude_options">
<item>3</item>
<item>5</item>
<item>6</item>
<item>7</item>
<item>8</item>
</string-array>
<array name="update_freq_values">
<item>1</item>
<item>5</item>
<item>10</item>
<item>15</item>
<item>60</item>
</array>
</resources>
我试图用整数数组，但没有帮助。我究竟做错了什么？请帮忙。谢谢你。
I tried using integer-array but that didn't help. What am I doing wrong? Please help. Thanks.
推荐答案
我有同样的问题 - 从previous例如在节省$ P $书的时候使用不同的数据类型，用户preference数据pference数据。
I had the same problem - the user preference data from the previous example in the book used different data types when saving the preference data.
解决的办法是启动AVD时摆脱老用户preferences的简单检查清除用户数据复选框。
The solution is to simply check the 'clear user data' checkbox when starting the AVD to get rid of the old user preferences.
这篇关于ClassCastException异常在preferenceActivity的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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