Przykład MultiSelectListPreference

Question

Mam trudności ze znalezieniem dobrego przykładu MultiSelectListPreference w interfejsie API systemu Android. Widziałem wiele odniesień do this blog, a to jest wynik końcowy, którego pragnę, nie chcę tworzyć klasy dla każdej preferencji wielokrotnego wyboru, którą chcę zaimplementować. Docelowo chcę zobaczyć xml preferencji dla prostego multi-select okna (które propaguje wartości dla dynamicznie), a także na wezwanie do addPreferencesFromResource(R.xml.preferences);

Obecnie mam:

<MultiSelectListPreference 
    android:defaultValue="" 
    android:enabled="true" 
    android:entries="@array/pref_default_entries" 
    android:entryValues="@array/pref_default_values" 
    android:key="TargetList" 
    android:persistent="true" 
    android:summary="@string/TargetSummary" 
    android:title="@string/TargetTitle" /> 

i gdy próbuję zadzwonić addPreferencesFromResource w mojej działalności onCreate zadzwonić otrzymuję następujący błąd:

06-18 13:59:30.690: E/AndroidRuntime(6052): FATAL EXCEPTION: main 
06-18 13:59:30.690: E/AndroidRuntime(6052): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tracker/com.tracker.TrackerActivity}: android.view.InflateException: Binary XML file line #37: Error inflating class java.lang.reflect.Constructor 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1818) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1834) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.app.ActivityThread.access$500(ActivityThread.java:122) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1027) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.os.Handler.dispatchMessage(Handler.java:99) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.os.Looper.loop(Looper.java:132) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.app.ActivityThread.main(ActivityThread.java:4126) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at java.lang.reflect.Method.invokeNative(Native Method) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at java.lang.reflect.Method.invoke(Method.java:491) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:844) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at dalvik.system.NativeStart.main(Native Method) 
06-18 13:59:30.690: E/AndroidRuntime(6052): Caused by: android.view.InflateException: Binary XML file line #37: Error inflating class java.lang.reflect.Constructor 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.GenericInflater.createItem(GenericInflater.java:397) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.GenericInflater.onCreateItem(GenericInflater.java:417) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.GenericInflater.createItemFromTag(GenericInflater.java:428) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.GenericInflater.rInflate(GenericInflater.java:481) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.GenericInflater.inflate(GenericInflater.java:326) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.GenericInflater.inflate(GenericInflater.java:263) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.PreferenceManager.inflateFromResource(PreferenceManager.java:269) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.PreferenceActivity.addPreferencesFromResource(PreferenceActivity.java:1366) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at com.tracker.TrackerActivity.onCreate(TrackerActivity.java:30) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1050) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1782) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  ... 11 more 
06-18 13:59:30.690: E/AndroidRuntime(6052): Caused by: java.lang.reflect.InvocationTargetException 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at java.lang.reflect.Constructor.constructNative(Native Method) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at java.lang.reflect.Constructor.newInstance(Constructor.java:416) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.GenericInflater.createItem(GenericInflater.java:383) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  ... 21 more 
06-18 13:59:30.690: E/AndroidRuntime(6052): Caused by: java.lang.NullPointerException 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.content.res.AssetManager.getResourceTextArray(AssetManager.java:215) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.content.res.Resources.getTextArray(Resources.java:435) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.content.res.TypedArray.getTextArray(TypedArray.java:628) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.MultiSelectListPreference.onGetDefaultValue(MultiSelectListPreference.java:210) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.Preference.<init>(Preference.java:257) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.DialogPreference.<init>(DialogPreference.java:69) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.DialogPreference.<init>(DialogPreference.java:90) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  at android.preference.MultiSelectListPreference.<init>(MultiSelectListPreference.java:49) 
06-18 13:59:30.690: E/AndroidRuntime(6052):  ... 24 more 

czekam na odpowiedź!

Answer 1

Sigrist jest poprawna, aby rozwiązać ten początkowy błąd widzisz. Wymagane są wartości domyślne, nawet jeśli są puste. Pomogło mi to, że chcę podać wartości pod RUNTIME, ale nie zadzieraj z pełną implementacją.

Zobacz ten kod, jak podać wartości w czasie wykonywania, bez konieczności obsługi pełnej implementacji.

public class CalendarListPreference extends MultiSelectListPreference { 

ContentResolver cr; 
Cursor cursor; 
String[] projection = new String[] {CalendarContract.Calendars.NAME, CalendarContract.Calendars.CALENDAR_DISPLAY_NAME}; 
String selection = "(" + CalendarContract.Calendars.VISIBLE + " = ?)"; 
String[] selectionArgs = new String[] { "1" }; 

public CalendarListPreference(Context context, AttributeSet attrs) { 
    super(context, attrs); 

    List<CharSequence> entries = new ArrayList<CharSequence>(); 
    List<CharSequence> entriesValues = new ArrayList<CharSequence>(); 

    cr = context.getContentResolver(); 
    cursor = cr.query(CalendarContract.Calendars.CONTENT_URI, projection, selection, selectionArgs, null); 

    while (cursor.moveToNext()) { 
     String name = cursor.getString(0); 
     String displayName = cursor.getString(1); 

     entries.add(name); 
     entriesValues.add(displayName); 
    } 

    setEntries(entries.toArray(new CharSequence[]{})); 
    setEntryValues(entriesValues.toArray(new CharSequence[]{})); 
} 
} 

W moim strings.xml

<string-array name="pref_calendar_list_default"> 
</string-array> 

W moim preferences.xml

<com.mynameistodd.autovolume.CalendarListPreference 
android:defaultValue="@array/pref_calendar_list_default" 
android:key="@string/pref_calendar_list_key" 
android:summary="@string/pref_calendar_list_summary" 
android:title="@string/pref_calendar_list_title" 
android:dependency="@string/pref_calendar_enabled_key"/> 

wiem, że to jest trochę stary pytanie, ale bardzo mi pomógł, więc tutaj jest moja odpowiedź!

Answer 2

musisz określić z obiektem defaultValues ​​

<MultiSelectListPreference 
     android:dialogTitle="@string/mode_repeat" 
     android:key="mode_repeat" 
     android:summary=""   
     android:title="@string/mode_repeat" 
     android:entries="@array/weekdays" 
     android:entryValues="@array/weekdays_values" 
     android:defaultValue="@array/empty_array" 
     /> 

Jeśli nie chcesz, wartości domyślne, należy utworzyć pustą tablicę w strings.xml

<string-array name="empty_array"/> 

Answer 3

Mam utworzoną MultiSelectListPreference dla urządzeń uruchomienie Androida w interfejsie API wcześniej niż na poziomie 11.

• Obsługuje listę otrzymywania list wyboru SELLLISTEN ect wartości.
• Obsługuje automatyczne ustawianie podsumowania.
• Załączone przykłady.

https://gist.github.com/cardil/4754571

package pl.wavesoftware.widget; 

import java.util.ArrayList; 
import java.util.Arrays; 
import java.util.Iterator; 
import java.util.List; 

import android.app.AlertDialog.Builder; 
import android.content.Context; 
import android.content.DialogInterface; 
import android.content.DialogInterface.OnMultiChoiceClickListener; 
import android.content.res.TypedArray; 
import android.preference.ListPreference; 
import android.util.AttributeSet; 

public class MultiSelectListPreference extends ListPreference { 

    private String separator; 
    private static final String DEFAULT_SEPARATOR = "\u0001\u0007\u001D\u0007\u0001"; 
    private boolean[] entryChecked; 

    public MultiSelectListPreference(Context context, AttributeSet attributeSet) { 
     super(context, attributeSet); 
     entryChecked = new boolean[getEntries().length]; 
     separator = DEFAULT_SEPARATOR; 
    } 

    public MultiSelectListPreference(Context context) { 
     this(context, null); 
    } 

    @Override 
    protected void onPrepareDialogBuilder(Builder builder) { 
     CharSequence[] entries = getEntries(); 
     CharSequence[] entryValues = getEntryValues(); 
     if (entries == null || entryValues == null 
       || entries.length != entryValues.length) { 
      throw new IllegalStateException(
        "MultiSelectListPreference requires an entries array and an entryValues " 
          + "array which are both the same length"); 
     } 

     restoreCheckedEntries(); 
     OnMultiChoiceClickListener listener = new DialogInterface.OnMultiChoiceClickListener() { 
      public void onClick(DialogInterface dialog, int which, boolean val) { 
       entryChecked[which] = val; 
      } 
     }; 
     builder.setMultiChoiceItems(entries, entryChecked, listener); 
    } 

    private CharSequence[] unpack(CharSequence val) { 
     if (val == null || "".equals(val)) { 
      return new CharSequence[0]; 
     } else { 
      return ((String) val).split(separator); 
     } 
    } 

    /** 
    * Gets the entries values that are selected 
    * 
    * @return the selected entries values 
    */ 
    public CharSequence[] getCheckedValues() { 
     return unpack(getValue()); 
    } 

    private void restoreCheckedEntries() { 
     CharSequence[] entryValues = getEntryValues(); 

     // Explode the string read in sharedpreferences 
     CharSequence[] vals = unpack(getValue()); 

     if (vals != null) { 
      List<CharSequence> valuesList = Arrays.asList(vals); 
      for (int i = 0; i < entryValues.length; i++) { 
       CharSequence entry = entryValues[i]; 
       entryChecked[i] = valuesList.contains(entry); 
      } 
     } 
    } 

    @Override 
    protected void onDialogClosed(boolean positiveResult) { 
     List<CharSequence> values = new ArrayList<CharSequence>(); 

     CharSequence[] entryValues = getEntryValues(); 
     if (positiveResult && entryValues != null) { 
      for (int i = 0; i < entryValues.length; i++) { 
       if (entryChecked[i] == true) { 
        String val = (String) entryValues[i]; 
        values.add(val); 
       } 
      } 

      String value = join(values, separator); 
      setSummary(prepareSummary(values)); 
      setValueAndEvent(value); 
     } 
    } 

    private void setValueAndEvent(String value) { 
     if (callChangeListener(unpack(value))) { 
      setValue(value); 
     } 
    } 

    private CharSequence prepareSummary(List<CharSequence> joined) { 
     List<String> titles = new ArrayList<String>(); 
     CharSequence[] entryTitle = getEntries(); 
     CharSequence[] entryValues = getEntryValues(); 
     int ix = 0; 
     for (CharSequence value : entryValues) { 
      if (joined.contains(value)) { 
       titles.add((String) entryTitle[ix]); 
      } 
      ix += 1; 
     } 
     return join(titles, ", "); 
    } 

    @Override 
    protected Object onGetDefaultValue(TypedArray typedArray, int index) { 
     return typedArray.getTextArray(index); 
    } 

    @Override 
    protected void onSetInitialValue(boolean restoreValue, 
      Object rawDefaultValue) { 
     String value = null; 
     CharSequence[] defaultValue; 
     if (rawDefaultValue == null) { 
      defaultValue = new CharSequence[0]; 
     } else { 
      defaultValue = (CharSequence[]) rawDefaultValue; 
     } 
     List<CharSequence> joined = Arrays.asList(defaultValue); 
     String joinedDefaultValue = join(joined, separator); 
     if (restoreValue) { 
      value = getPersistedString(joinedDefaultValue); 
     } else { 
      value = joinedDefaultValue; 
     } 

     setSummary(prepareSummary(Arrays.asList(unpack(value)))); 
     setValueAndEvent(value); 
    } 

    /** 
    * Joins array of object to single string by separator 
    * 
    * Credits to kurellajunior on this post 
    * http://snippets.dzone.com/posts/show/91 
    * 
    * @param iterable 
    *   any kind of iterable ex.: <code>["a", "b", "c"]</code> 
    * @param separator 
    *   separetes entries ex.: <code>","</code> 
    * @return joined string ex.: <code>"a,b,c"</code> 
    */ 
    protected static String join(Iterable<?> iterable, String separator) { 
     Iterator<?> oIter; 
     if (iterable == null || (!(oIter = iterable.iterator()).hasNext())) 
      return ""; 
     StringBuilder oBuilder = new StringBuilder(String.valueOf(oIter.next())); 
     while (oIter.hasNext()) 
      oBuilder.append(separator).append(oIter.next()); 
     return oBuilder.toString(); 
    } 

}