title: creating a DialogPreference from XML
body: <p>I have been attempting to use an <code>android.preference.DialogPreference</code> inflated from XML, but the documentation seems to be missing some essential bits, and I cannot find a working example anywhere.  My XML now looks like this (I tried many permutations but this seems like a reasonable minimum):</p>
  
  <pre><code>&lt;DialogPreference
  android:key="funThing" android:title="Fun Thing"
  android:dialogLayout="@layout/fun_layout"
  android:positiveButtonText="OK"
  android:negativeButtonText="Cancel"
  /&gt;
  </code></pre>
  
  <p>My supposition at this point is that it is required to subclass <code>DialogPreference</code> and not to use it directly. For one, I cannot find a way to associate the actual preference value with an element in the dialog itself, which upon reflection is kind of a giveaway.  And also, looking at <a href="http://android.git.kernel.org/?p=platform/frameworks/base.git;a=blob;f=core/java/android/preference/DialogPreference.java" rel="noreferrer">the source to <code>DialogPreference.java</code></a> seems to confirm it. And I also just noticed that <a href="http://developer.android.com/reference/android/preference/DialogPreference.html" rel="noreferrer">the official documentation</a> refers to it as a "base class". But at very least, it would be nice to establish a definitive-enough source on the net which would help the next N people figure this out faster than I did.</p>
  
  <p>For the record, the logfile looks like this:</p>
  
  <pre><code>I/ActivityManager(   61): Starting: Intent { cmp=org.jeremy.android/.PreferencesActivity } from pid 2755
  W/Resources( 2755): Converting to string: TypedValue{t=0x10/d=0x4b0 a=-1}
  W/Resources( 2755): Converting to string: TypedValue{t=0x10/d=0x20 a=-1}
  D/AndroidRuntime( 2755): Shutting down VM
  W/dalvikvm( 2755): threadid=1: thread exiting with uncaught exception (group=0x40015560)
  E/AndroidRuntime( 2755): FATAL EXCEPTION: main
  E/AndroidRuntime( 2755): java.lang.RuntimeException: Unable to start activity ComponentInfo{org.jeremy.android/org.jeremy.android.PreferencesActivity}: android.view.InflateException: Binary XML file line #28: Error inflating class java.lang.reflect.Constructor
  E/AndroidRuntime( 2755):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
  E/AndroidRuntime( 2755):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
  E/AndroidRuntime( 2755):    at android.app.ActivityThread.access$1500(ActivityThread.java:117)
  E/AndroidRuntime( 2755):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
  E/AndroidRuntime( 2755):    at android.os.Handler.dispatchMessage(Handler.java:99)
  E/AndroidRuntime( 2755):    at android.os.Looper.loop(Looper.java:123)
  E/AndroidRuntime( 2755):    at android.app.ActivityThread.main(ActivityThread.java:3683)
  E/AndroidRuntime( 2755):    at java.lang.reflect.Method.invokeNative(Native Method)
  E/AndroidRuntime( 2755):    at java.lang.reflect.Method.invoke(Method.java:507)
  E/AndroidRuntime( 2755):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
  E/AndroidRuntime( 2755):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
  E/AndroidRuntime( 2755):    at dalvik.system.NativeStart.main(Native Method)
  E/AndroidRuntime( 2755): Caused by: android.view.InflateException: Binary XML file line #28: Error inflating class java.lang.reflect.Constructor
  E/AndroidRuntime( 2755):    at android.preference.GenericInflater.createItem(GenericInflater.java:397)
  E/AndroidRuntime( 2755):    at android.preference.GenericInflater.onCreateItem(GenericInflater.java:417)
  E/AndroidRuntime( 2755):    at android.preference.GenericInflater.createItemFromTag(GenericInflater.java:428)
  E/AndroidRuntime( 2755):    at android.preference.GenericInflater.rInflate(GenericInflater.java:481)
  E/AndroidRuntime( 2755):    at android.preference.GenericInflater.rInflate(GenericInflater.java:493)
  E/AndroidRuntime( 2755):    at android.preference.GenericInflater.inflate(GenericInflater.java:326)
  E/AndroidRuntime( 2755):    at android.preference.GenericInflater.inflate(GenericInflater.java:263)
  E/AndroidRuntime( 2755):    at android.preference.PreferenceManager.inflateFromResource(PreferenceManager.java:251)
  E/AndroidRuntime( 2755):    at android.preference.PreferenceActivity.addPreferencesFromResource(PreferenceActivity.java:262)
  E/AndroidRuntime( 2755):    at org.jeremy.android.PreferencesActivity.onCreate(PreferencesActivity.java:40)
  E/AndroidRuntime( 2755):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
  E/AndroidRuntime( 2755):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
  E/AndroidRuntime( 2755):    ... 11 more
  E/AndroidRuntime( 2755): Caused by: java.lang.InstantiationException: android.preference.DialogPreference
  E/AndroidRuntime( 2755):    at java.lang.reflect.Constructor.constructNative(Native Method)
  E/AndroidRuntime( 2755):    at java.lang.reflect.Constructor.newInstance(Constructor.java:415)
  E/AndroidRuntime( 2755):    at android.preference.GenericInflater.createItem(GenericInflater.java:383)
  E/AndroidRuntime( 2755):    ... 22 more
  W/ActivityManager(   61):   Force finishing activity org.jeremy.android/.PreferencesActivity
  W/ActivityManager(   61):   Force finishing activity org.jeremy.android/.SplashActivity
  </code></pre>