我在onCheckedChanged监听器上收到了一个nullpointer异常。
这是我班级的代码：
public class Instellingen extends PreferenceActivity implements OnCheckedChangeListener{
public static final int mode= Activity.MODE_PRIVATE;
public static final String KEY_LOCKACTIONS = "lockactions";
public static final String KEY_VERSIE = "Versie";
public static final String KEY_CHAUFFEUR = "Chauffeur";
public static final String KEY_LATITUDE = "Latitude";
public static final String KEY_LONGITUDE = "Longitude";
public static final String KEY_NEEDLOCUPDATE = "NeedLocUpdate";
public static final String KEY_NEEDAPPUPDATE = "NeedAppUpdate";
public static final String KEY_NEEDSYNC = "NeedSync";
public static final String KEY_SYNCCONTENT = "NeedSyncContent";
public static final String KEY_THREADCOUNT = "ThreadCount";
public static final String KEY_FREESYNCTHREAD = "FreeSyncThread";
public static final long version = 0;
static SharedPreferences mySharedPreferences;
CheckBox cbLogFile, cbRemainLogged;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferences);
mySharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
cbRemainLogged = (CheckBox)findViewById(R.id.cbRemainLoggedPreferences);
cbRemainLogged.setOnCheckedChangeListener(this);
}
public static SharedPreferences.Editor GetEditor(Context context)
{
mySharedPreferences = context.getSharedPreferences("KCStandaardSettings", mode);
return mySharedPreferences.edit();
}
public static void SetBoolean(Context context, String Name, Boolean Value)
{
if (Name == KEY_LOCKACTIONS) {
TLogFile.appendLog("i", KEY_LOCKACTIONS, Value.toString());
}
SharedPreferences.Editor editor = GetEditor(context);
editor.putBoolean(Name,Value);
editor.commit();
}
public static Boolean GetBoolean(Context context, String Name)
{
mySharedPreferences = context.getSharedPreferences("KCStandaardSettings", mode);
return mySharedPreferences.getBoolean(Name, false);
}
public static void SetFloat(Context context, String Name, Float Value)
{
SharedPreferences.Editor editor = GetEditor(context);
editor.putFloat(Name,Value);
editor.commit();
}
public static Float GetFloat(Context context, String Name)
{
mySharedPreferences = context.getSharedPreferences("KCStandaardSettings", mode);
return mySharedPreferences.getFloat(Name, 0);
}
public static void SetDouble(Context context, String Name, Double Value)
{
SharedPreferences.Editor editor = GetEditor(context);
Float f = new Float(Value);
editor.putFloat(Name,f);
editor.commit();
}
public static Double GetDouble(Context context, String Name)
{
mySharedPreferences = context.getSharedPreferences("KCStandaardSettings", mode);
return (double) mySharedPreferences.getFloat(Name, 0);
}
public static void SetLong(Context context, String Name, Long Value)
{
SharedPreferences.Editor editor = GetEditor(context);
editor.putLong(Name,Value);
editor.commit();
}
public static Long GetLong(Context context, String Name)
{
mySharedPreferences = context.getSharedPreferences("KCStandaardSettings", mode);
return mySharedPreferences.getLong(Name, 0);
}
public static void SetString(Context context, String Name, String Value)
{
SharedPreferences.Editor editor = GetEditor(context);
editor.putString(Name,Value);
editor.commit();
}
public static String GetString(Context context, String Name)
{
mySharedPreferences = context.getSharedPreferences("KCStandaardSettings", mode);
return mySharedPreferences.getString(Name, "");
}
public static void SetInt(Context context, String Name, int Value)
{
SharedPreferences.Editor editor = GetEditor(context);
editor.putInt(Name,Value);
editor.commit();
}
public static int GetInt(Context context, String Name)
{
mySharedPreferences = context.getSharedPreferences("KCStandaardSettings", mode);
return mySharedPreferences.getInt(Name, 0);
}
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
switch(buttonView.getId()){
case R.id.cbRemainLoggedPreferences:
Instellingen.SetBoolean(this, "RemainLoggedIn", isChecked);
break;
}
}
}
这是错误日志：
06-03 09:18:03.603: E/AndroidRuntime(14208): FATAL EXCEPTION: main
06-03 09:18:03.603: E/AndroidRuntime(14208): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.koeriers.standaard/com.koeriers.standaard.Instellingen}: java.lang.NullPointerException
06-03 09:18:03.603: E/AndroidRuntime(14208): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2246)
06-03 09:18:03.603: E/AndroidRuntime(14208): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2296)
06-03 09:18:03.603: E/AndroidRuntime(14208): at android.app.ActivityThread.access$700(ActivityThread.java:151)
06-03 09:18:03.603: E/AndroidRuntime(14208): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1281)
06-03 09:18:03.603: E/AndroidRuntime(14208): at android.os.Handler.dispatchMessage(Handler.java:99)
06-03 09:18:03.603: E/AndroidRuntime(14208): at android.os.Looper.loop(Looper.java:137)
06-03 09:18:03.603: E/AndroidRuntime(14208): at android.app.ActivityThread.main(ActivityThread.java:5293)
06-03 09:18:03.603: E/AndroidRuntime(14208): at java.lang.reflect.Method.invokeNative(Native Method)
06-03 09:18:03.603: E/AndroidRuntime(14208): at java.lang.reflect.Method.invoke(Method.java:511)
06-03 09:18:03.603: E/AndroidRuntime(14208): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
06-03 09:18:03.603: E/AndroidRuntime(14208): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
06-03 09:18:03.603: E/AndroidRuntime(14208): at dalvik.system.NativeStart.main(Native Method)
06-03 09:18:03.603: E/AndroidRuntime(14208): Caused by: java.lang.NullPointerException
06-03 09:18:03.603: E/AndroidRuntime(14208): at com.koeriers.standaard.Instellingen.onCreate(Instellingen.java:38)
06-03 09:18:03.603: E/AndroidRuntime(14208): at android.app.Activity.performCreate(Activity.java:5250)
06-03 09:18:03.603: E/AndroidRuntime(14208): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1097)
06-03 09:18:03.603: E/AndroidRuntime(14208): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2210)
06-03 09:18:03.603: E/AndroidRuntime(14208): ... 11 more
这是我班级的xml。这个在addPreferencesFromResource（）;
中调用<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >
<EditTextPreference
android:id="@+id/etLicensePreferences"
android:key="LicentieCode"
android:title="LicentieCode: " />
<CheckBoxPreference
android:id="@+id/cbRemainLoggedPreferences"
android:defaultValue="false"
android:key="cbLoggedOn"
android:title="@string/remainLoggedIn" />
<CheckBoxPreference
android:id="@+id/cbNotificationSound"
android:defaultValue="false"
android:key="cbNotificationSound"
android:title="@string/Sound" />
<CheckBoxPreference
android:id="@+id/cbWidgetAllPreferences"
android:defaultValue="true"
android:key="cbWidgetAll"
android:title="Toon in de Widget de tab met alle berichten" />
<CheckBoxPreference
android:id="@+id/cbWidgetUnreadPreferences"
android:defaultValue="true"
android:key="cbWidgetUnread"
android:title="Toon in de Widget de tab met ongelezen berichten" />
<CheckBoxPreference
android:id="@+id/cbWidgetReadPreferences"
android:defaultValue="true"
android:key="cbWidgetRead"
android:title="Toon in de Widget de tab met gelezen berichten" />
</PreferenceScreen>
答案 0 :(得分：0)
PreferenceActivity不用于定义其中的视图。您可以查看这些链接。制作单独的java文件以扩充您的视图。请查看以下示例：
http://viralpatel.net/blogs/android-preferences-activity-example/
http://androidresearch.wordpress.com/2012/03/09/creating-a-preference-activity-in-android/
http://marakana.com/bookshelf/main_building_blocks_tutorial/preference_activity.html
如果setContentView(...)
onCreate()，则无法找到您的观看次数