A DialogPreference isn't an Activity in its own right. It's just a Preference which displays a Dialog when clicked.
The problem is that there's no obvious way programmatically click a Preference. However, since you're using DialogPreference you've already got you own subclass of it. So we can solve our problem by adding the following method to your subclass of DialogPreference:
//Expose the protected onClick method
void show() {
onClick();
}
Then in the onCreate() of your PreferencesActivity you'll have something like this to load the preferences from your XML file:
// Load the preferences from an XML resource
addPreferencesFromResource(R.xml.preferences);
After that you can put some code like this:
booleanProp = true; //set this to the value of the property you're checking
if (! booleanProp) {
//Find the Preference via its android:key
//MyDialogPreference is your subclasss of DialogPreference
MyDialogPreference dp = (MyDialogPreference)getPreferenceScreen().findPreference("dialog_preference");
dp.show();
}
This is a bit of hack, as exposing protected methods isn't ideal, but it does work.
Another option would be to replace the Dialog with a PrefenceActivity which contained all the options you wish to maintain and then you could launch it via an Intent, but I'm assuming there's a good reason that you want your own custom Dialog with a specific layout. If you do want a second PreferenceActivity you can add it to your preferences XML file as follows:
<PreferenceScreen
android:title="@string/title_of_preference"
android:summary="@string/summary_of_preference">
<intent android:action="your.action.goes.HERE"/>
</PreferenceScreen>
