Android MultiSelectListPreference 示例

MultiSelectListPreference example

提问by mohbandy

I am having a hard time trying to find a good example of the MultiSelectListPreference provided in the Android API. I have seen many references to this blog, and tho this is the end result I desire, I don't want to create a class for each multi-select preference I want to implement. Ultimately I want to see the preferences xml for a simple multi-select dialog (which i will populate the values for dynamically), as well to the call to addPreferencesFromResource(R.xml.preferences);

我很难找到 Android API 中提供的 MultiSelectListPreference 的一个很好的例子。我已经看到很多对这个博客的引用，虽然这是我想要的最终结果，但我不想为我想要实现的每个多选首选项创建一个类。最终，我想查看一个简单的多选对话框的首选项 xml（我将动态填充值），以及调用addPreferencesFromResource(R.xml.preferences);

Currently, I have:

目前，我有：

<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" />

and when I try to call addPreferencesFromResource in my Activities onCreate call I am getting the following error:

当我尝试在我的活动 onCreate 调用中调用 addPreferencesFromResource 时，我收到以下错误：

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.access0(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

I look forward to your reply!

我期待你的回复！

采纳答案by Todd DeLand

Sigrist is correct, to solve the initial error you are seeing. It needs default values provided, even if its empty. This helped me in that I want to provide values at RUNTIME, but not mess with the full implementation.

Sigrist 是正确的，可以解决您所看到的初始错误。它需要提供默认值，即使它是空的。这对我有帮助，因为我想在RUNTIME提供值，但不会弄乱完整的实现。

See this code for how I provide values at runtime, while not having to handle the full implementation.

请参阅此代码了解我如何在运行时提供值，而不必处理完整的实现。

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[]{}));
}
}

In my strings.xml

在我的 strings.xml 中

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

In my preferences.xml

在我的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"/>

I know this is a bit of an old question, but it helped me, so here is my answer!

我知道这是一个老问题，但它帮助了我，所以这是我的答案！

回答by Sigrist

You need to specify the defaultValues property

您需要指定 defaultValues 属性

<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"
        />

If you don't want default values, create an empty array in your strings.xml

如果您不想要默认值，请在 strings.xml 中创建一个空数组

<string-array name="empty_array"/>

回答by Chris Suszyński

I've created MultiSelectListPreference for devices running Android in the API earlier than level 11.

我已经为 API 中运行 Android 的设备创建了 MultiSelectListPreference 早于级别 11。

• Supports ChangeListener receiving list of selected values.
• Supports automatically setting of summary.
• Examples attached.

• 支持 ChangeListener 接收选定值的列表。
• 支持自动设置摘要。
• 附上例子。

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

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();
    }

}

回答by Andrew

I got same error because I defined my array.xmlwith entries in values-large, but didn't have the file in the default valuespackage. So I just moved array.xmlinto values.

我遇到了同样的错误，因为我使用values-large 中的条目定义了我的array.xml，但在默认值包中没有该文件。所以我只是将array.xml移动到values 中。

回答by Javier

You can do it on runtime just setting values/entries like this

您可以在运行时执行此操作，只需像这样设置值/条目

findPreference<MultiSelectListPreference>(getString(R.string.preference_key_some_apps))?.apply {
            val entryDisplay =
                listOf("Facebook Messenger", "Whatsapp", "Telegram", "SMS").toTypedArray()
            val entryValuesApps = listOf(
                Constants.FACEBOOK_MESSENGER_PACKAGE_NAME,
                Constants.WHATSAPP_PACKAGE_NAME,
                Constants.TELEGRAM_PACKAGE_NAME,
                Constants.SMS_MESSENGER_PACKAGE_NAME_HOLDER
            ).toTypedArray()

            entries = entryDisplay
            this.entryValues = entryValuesApps
        }