[Android] Dynamic Array ListPreference

需求是，某一個下拉欄位可以選擇的值是動態與其他欄位做聯動。

解決辦法：

https://stackoverflow.com/questions/6136770/android-dynamic-array-listpreference

Place preferences.xml in res/xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">

    <PreferenceCategory android:title="Some title">     

        <ListPreference android:key="default_category"
            android:title="Dynamic categories" android:summary="Dynamic categories summary"
            android:defaultValue="0" />
    </PreferenceCategory>
</PreferenceScreen>

In your activity that extends PreferenceActivity you do something like this in onCreate().

ListPreference listPreferenceCategory = (ListPreference) findPreference("default_category");
if (listPreferenceCategory != null) {
    ArrayList<Category> categoryList = getCategories();
    CharSequence entries[] = new String[categoryList.size()];
    CharSequence entryValues[] = new String[categoryList.size()];
    int i = 0;
    for (Category category : categoryList) {
        entries[i] = category.getCategoryName();
        entryValues[i] = Integer.toString(i);
        i++;
    }
    listPreferenceCategory.setEntries(entries);
    listPreferenceCategory.setEntryValues(entryValues);
}

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範例2：

https://stackoverflow.com/questions/6474707/how-to-fill-listpreference-dynamically-when-onpreferenceclick-is-triggered

Every XML element in Android can be created programmatically as the element name is also a Java class. Hence you can create a ListPreference in code:

CharSequence[] entries = { "One", "Two", "Three" };
CharSequence[] entryValues = { "1", "2", "3" };
ListPreference lp = new ListPreference(this);
lp.setEntries(entries);
lp.setEntryValues(entryValues);

You could alternatively create it in XML then add the entries/entry values in code:

CharSequence[] entries = { "One", "Two", "Three" };
CharSequence[] entryValues = { "1", "2", "3" };
ListPreference lp = (ListPreference)findPreference("list_key_as_defined_in_xml");
lp.setEntries(entries);
lp.setEntryValues(entryValues);