ListPreference dependency

Question

I have a ListPreference which look something like this:

<ListPreference android:title="Choose item" android:summary="..." android:key="itemList" android:defaultValue="item1" android:entries="@array/items" android:entryValues="@array/itemValues" /> 

Then, I have another preference which should only be enabled if "item3" is selected in the ListPreference.

Can I somehow accomplish this with android:dependency? Something like android:dependency="itemList:item3"

Thanks!

Answer 1

The only way you can do something like this is programmaticly.

You'd have to set up an change listener on the ListPreference and then enable/disable the other one.

itemList = (ListPreference)findPreference("itemList"); itemList2 = (ListPreference)findPreference("itemList2"); itemList.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {   public boolean onPreferenceChange(Preference preference, Object newValue) {     final String val = newValue.toString();     int index = itemList.findIndexOfValue(val);     if(index==3)       itemList2.setEnabled(true);     else       itemList2.setEnabled(false);     return true;   } }); 

If I were you I wouldn't even show the second preference if the first isn't set properly. To do that you have to declare the preference manually (not in the XML) and add/remove it instead of enabling/disabling.

Now isn't this the bestest answer you've ever seen?!

Emmanuel

Answer 2

Subclass ListPreference class, and override setValue and shouldDisableDependence methods.

setValue will call notifyDependencyChange(shouldDisableDependents()) after super.setValue when the value is actually changed.

shouldDisableDependence returns false only if the current value is item3, or any other desired value stored in mDepedenceValue.

@Override public void setValue(String value) {     String mOldValue = getValue();     super.setValue(value);     if (!value.equals(mOldValue)) {         notifyDependencyChange(shouldDisableDependents());     } }  @Override public boolean shouldDisableDependents() {     boolean shouldDisableDependents = super.shouldDisableDependents();     String value = getValue();     return shouldDisableDependents || value == null || !value.equals(mDepedenceValue); }