Question

这是我的偏好.xml

<?xml version="1.0" encoding="utf-8"?>

<ListPreference
    android:key="KEY_1"
    android:title="Title"
    android:summary="Summary"
    android:dialogTitle="Dialog"
    />
<ListPreference
    android:key="KEY_2"
     />   
<ListPreference
    android:key="KEY_3"
     />   
<ListPreference
    android:key="KEY_4"
     />

这是Settings.java：

public class Settings extends PreferenceActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    addPreferencesFromResource(R.xml.preferences);

// some methods to generate entries and values for ListPreference
final List List_1 = // something
final List List_2 = // something
final List List_3 = // something

String[] entry_1 = List_1.toArray(new String[List_1.size()]);
String[] entry_2 = List_2.toArray(new String[List_2.size()]);
String[] entry_3 = List_3.toArray(new String[List_3.size()]);

String[] value_1 = List_1.toArray(new String[List_1.size()]);
String[] value_2 = List_2.toArray(new String[List_2.size()]);
String[] value_3 = List_3.toArray(new String[List_3.size()]);


    // set arrays for entries and values    
 final ListPreference lp1 = (ListPreference)findPreference("KEY_1");
 lp1.setEntries(entry_1);
 lp1.setEntryValues(value_2); 

ListPreference lp2 = (ListPreference)findPreference("KEY_2");
lp2.setEntries(entry_2);
lp2.setEntryValues(value_1);

ListPreference lp3 = (ListPreference)findPreference("KEY_3");
lp3.setEntries(entry_2);
lp3.setEntryValues(value_2);

ListPreference lp4 = (ListPreference)findPreference("KEY_4");
lp4.setEntries(entry_2);
lp4.setEntryValues(value_3);

// update lp2, lp3, lp4

        lp1.setOnPreferenceChangeListener(new OnPreferenceChangeListener() {
            @Override
            public boolean onPreferenceChange(Preference preference, Object newValue) {
                String listValue = (String) newValue;

                ListPreference lp2 = (ListPreference)findPreference("KEY_2");
                lp2.setDefaultValue(listValue);

                ListPreference lp3 = (ListPreference)findPreference("KEY_3");
                lp3.setDefaultValue(listValue);

                ListPreference lp4 = (ListPreference)findPreference("KEY_4");
                lp4.setDefaultValue(listValue);

                return true;
            }
        });
    }
}

这对我来说只适用一次。我在这里错过了什么来在lp2，lp3和lp4上进行更新？我想setDefaultValue只创建一次性输入到共享首选项？

Answer 1

我怀疑您的匿名侦听器是垃圾收集的 - 添加一些调试打印以查看是否调用了侦听器

lp1.setOnPreferenceChangeListener(new OnPreferenceChangeListener() {
    @Override
    public boolean onPreferenceChange(Preference preference, Object newValue) {
        Log.d("Listener", "I listen");
        String listValue = (String) newValue;
        // rest is the same
    }
});

如果您看不到调试打印，则将您的监听器移动到类字段并且：

public class Settings extends PreferenceActivity {

    private OnPreferenceChangeListener mListener=new OnPreferenceChangeListener(){
        @Override
        public boolean onPreferenceChange(Preference preference, Object newValue){
            // as before
        }
    };
    // etc - I guess the line below is in onCreate() - correct your formatting !
    lp1.setOnPreferenceChangeListener(mListener);
    }
}

Android：使用OnPreferenceChangeListener更新ListPreference

1 个答案: