从preferenceActivity ClassCastException异常 [英] ClassCastException from a PreferenceActivity
本文介绍了从preferenceActivity ClassCastException异常的处理方法,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
我每一次我尝试使用这个preference类得到一个ClassCastException,我想不通这是为什么。任何帮助将是非常美联社preciated。该行崩溃是添加preferencesFromResources
命令。
进口android.os.Bundle;
。进口的Android preference preferenceActivity;
公共类preferenceManager扩展preferenceActivity {
@燮pressWarnings(德precation)
@覆盖
保护无效的onCreate(包savedInstanceState){
// TODO自动生成方法存根
super.onCreate(savedInstanceState);
加preferencesFromResource(R.xml preferences。); //此行崩溃
}
}
preference.xml
< XML版本=1.0编码=UTF-8&GT?;
< preference的xmlns:机器人=http://schemas.android.com/apk/res/android>
<复选框preference
机器人:标题=@字符串/ startAnimation
安卓:设置defaultValue =真
机器人:总结=@字符串/ startAnimationDescription
机器人:关键=startAnimation/>
< / preference>
堆栈跟踪
11-18 19:04:19.165:E / AndroidRuntime(1362):未捕获的处理程序:螺纹主力退出,由于未捕获的异常
11-18 19:04:19.175:E / AndroidRuntime(1362):java.lang.RuntimeException的:无法启动的活动ComponentInfo{com.pearsonartphoto.psychictester/com.pearsonartphoto.psychictester.$p$pferenceManager}: java.lang.ClassCastException:。安卓preference preference
11-18 19:04:19.175:E / AndroidRuntime(1362):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
11-18 19:04:19.175:E / AndroidRuntime(1362):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
11-18 19:04:19.175:E / AndroidRuntime(1362):在android.app.ActivityThread.access $ 2200(ActivityThread.java:119)
11-18 19:04:19.175:E / AndroidRuntime(1362):在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1863)
11-18 19:04:19.175:E / AndroidRuntime(1362):在android.os.Handler.dispatchMessage(Handler.java:99)
11-18 19:04:19.175:E / AndroidRuntime(1362):在android.os.Looper.loop(Looper.java:123)
11-18 19:04:19.175:E / AndroidRuntime(1362):在android.app.ActivityThread.main(ActivityThread.java:4363)
11-18 19:04:19.175:E / AndroidRuntime(1362):在java.lang.reflect.Method.invokeNative(本机方法)
11-18 19:04:19.175:E / AndroidRuntime(1362):在java.lang.reflect.Method.invoke(Method.java:521)
11-18 19:04:19.175:E / AndroidRuntime(1362):在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:860)
11-18 19:04:19.175:E / AndroidRuntime(1362):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
11-18 19:04:19.175:E / AndroidRuntime(1362):在dalvik.system.NativeStart.main(本机方法)
11-18 19:04:19.175:E / AndroidRuntime(1362):java.lang.ClassCastException::所致。安卓preference preference
11-18 19:04:19.175:E / AndroidRuntime(1362):在安卓preference.GenericInflater.inflate(GenericInflater.java:320)
11-18 19:04:19.175:E / AndroidRuntime(1362):在安卓preference.GenericInflater.inflate(GenericInflater.java:263)
11-18 19:04:19.175:E / AndroidRuntime(1362):在安卓preference preferenceManager.inflateFromResource(preferenceManager.java:254)。
11-18 19:04:19.175:E / AndroidRuntime(1362):在安卓preference preferenceActivity.add preferencesFromResource(preferenceActivity.java:253)。
11-18 19:04:19.175:E / AndroidRuntime(1362):在com.pearsonartphoto.psychictester preferenceManager.onCreate(preferenceManager.java:12)。
11-18 19:04:19.175:E / AndroidRuntime(1362):在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11-18 19:04:19.175:E / AndroidRuntime(1362):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
11-18 19:04:19.175:E / AndroidRuntime(1362):11 ...更多
解决方案
XML文件的顶级元素应该是preferenceScreen没有preference
< XML版本=1.0编码=UTF-8&GT?;
< preferenceScreen的xmlns:机器人=http://schemas.android.com/apk/res/android>
<复选框preference
机器人:关键=pref_sync
机器人:标题=@字符串/ pref_sync
机器人:总结=@字符串/ pref_sync_summ
安卓:设置defaultValue =真/>
<表preference
机器人:依赖=pref_sync
机器人:关键=pref_syncConnectionType
机器人:标题=@字符串/ pref_syncConnectionType
机器人:dialogTitle =@字符串/ pref_syncConnectionType
机器人:项=@阵列/ pref_syncConnectionTypes_entries
机器人:entryValues =@阵列/ pref_syncConnectionTypes_values
安卓:设置defaultValue =@字符串/ pref_syncConnectionTypes_default/>
< / preferenceScreen>
从设置文档 <提取/ P>
I'm getting a classCastException every time I try to use this preference class, and I can't figure out why. Any help would be much appreciated. The line the crashes is the addPreferencesFromResources
command.
import android.os.Bundle;
import android.preference.PreferenceActivity;
public class PreferenceManager extends PreferenceActivity {
@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferences); // This line crashes
}
}
preference.xml
<?xml version="1.0" encoding="utf-8"?>
<Preference xmlns:android="http://schemas.android.com/apk/res/android" >
<CheckBoxPreference
android:title="@string/startAnimation"
android:defaultValue="true"
android:summary="@string/startAnimationDescription"
android:key="startAnimation" />
</Preference>
Stack Trace
11-18 19:04:19.165: E/AndroidRuntime(1362): Uncaught handler: thread main exiting due to uncaught exception
11-18 19:04:19.175: E/AndroidRuntime(1362): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.pearsonartphoto.psychictester/com.pearsonartphoto.psychictester.PreferenceManager}: java.lang.ClassCastException: android.preference.Preference
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.app.ActivityThread.access$2200(ActivityThread.java:119)
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.os.Handler.dispatchMessage(Handler.java:99)
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.os.Looper.loop(Looper.java:123)
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.app.ActivityThread.main(ActivityThread.java:4363)
11-18 19:04:19.175: E/AndroidRuntime(1362): at java.lang.reflect.Method.invokeNative(Native Method)
11-18 19:04:19.175: E/AndroidRuntime(1362): at java.lang.reflect.Method.invoke(Method.java:521)
11-18 19:04:19.175: E/AndroidRuntime(1362): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
11-18 19:04:19.175: E/AndroidRuntime(1362): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
11-18 19:04:19.175: E/AndroidRuntime(1362): at dalvik.system.NativeStart.main(Native Method)
11-18 19:04:19.175: E/AndroidRuntime(1362): Caused by: java.lang.ClassCastException: android.preference.Preference
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.preference.GenericInflater.inflate(GenericInflater.java:320)
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.preference.GenericInflater.inflate(GenericInflater.java:263)
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.preference.PreferenceManager.inflateFromResource(PreferenceManager.java:254)
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.preference.PreferenceActivity.addPreferencesFromResource(PreferenceActivity.java:253)
11-18 19:04:19.175: E/AndroidRuntime(1362): at com.pearsonartphoto.psychictester.PreferenceManager.onCreate(PreferenceManager.java:12)
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11-18 19:04:19.175: E/AndroidRuntime(1362): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
11-18 19:04:19.175: E/AndroidRuntime(1362): ... 11 more
解决方案
The top element of the xml file should be PreferenceScreen not Preference
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<CheckBoxPreference
android:key="pref_sync"
android:title="@string/pref_sync"
android:summary="@string/pref_sync_summ"
android:defaultValue="true" />
<ListPreference
android:dependency="pref_sync"
android:key="pref_syncConnectionType"
android:title="@string/pref_syncConnectionType"
android:dialogTitle="@string/pref_syncConnectionType"
android:entries="@array/pref_syncConnectionTypes_entries"
android:entryValues="@array/pref_syncConnectionTypes_values"
android:defaultValue="@string/pref_syncConnectionTypes_default" />
</PreferenceScreen>
Extracted from the settings documentation
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