1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.preference;
18
19import android.app.AlertDialog.Builder;
20import android.content.Context;
21import android.content.DialogInterface;
22import android.content.res.TypedArray;
23import android.os.Parcel;
24import android.os.Parcelable;
25import android.util.AttributeSet;
26
27import java.util.HashSet;
28import java.util.Set;
29
30/**
31 * A {@link Preference} that displays a list of entries as
32 * a dialog.
33 * <p>
34 * This preference will store a set of strings into the SharedPreferences.
35 * This set will contain one or more values from the
36 * {@link #setEntryValues(CharSequence[])} array.
37 *
38 * @attr ref android.R.styleable#MultiSelectListPreference_entries
39 * @attr ref android.R.styleable#MultiSelectListPreference_entryValues
40 */
41public class MultiSelectListPreference extends DialogPreference {
42    private CharSequence[] mEntries;
43    private CharSequence[] mEntryValues;
44    private Set<String> mValues = new HashSet<String>();
45    private Set<String> mNewValues = new HashSet<String>();
46    private boolean mPreferenceChanged;
47
48    public MultiSelectListPreference(
49            Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
50        super(context, attrs, defStyleAttr, defStyleRes);
51
52        final TypedArray a = context.obtainStyledAttributes(attrs,
53                com.android.internal.R.styleable.MultiSelectListPreference, defStyleAttr,
54                defStyleRes);
55        mEntries = a.getTextArray(com.android.internal.R.styleable.MultiSelectListPreference_entries);
56        mEntryValues = a.getTextArray(com.android.internal.R.styleable.MultiSelectListPreference_entryValues);
57        a.recycle();
58    }
59
60    public MultiSelectListPreference(Context context, AttributeSet attrs, int defStyleAttr) {
61        this(context, attrs, defStyleAttr, 0);
62    }
63
64    public MultiSelectListPreference(Context context, AttributeSet attrs) {
65        this(context, attrs, com.android.internal.R.attr.dialogPreferenceStyle);
66    }
67
68    public MultiSelectListPreference(Context context) {
69        this(context, null);
70    }
71
72    /**
73     * Sets the human-readable entries to be shown in the list. This will be
74     * shown in subsequent dialogs.
75     * <p>
76     * Each entry must have a corresponding index in
77     * {@link #setEntryValues(CharSequence[])}.
78     *
79     * @param entries The entries.
80     * @see #setEntryValues(CharSequence[])
81     */
82    public void setEntries(CharSequence[] entries) {
83        mEntries = entries;
84    }
85
86    /**
87     * @see #setEntries(CharSequence[])
88     * @param entriesResId The entries array as a resource.
89     */
90    public void setEntries(int entriesResId) {
91        setEntries(getContext().getResources().getTextArray(entriesResId));
92    }
93
94    /**
95     * The list of entries to be shown in the list in subsequent dialogs.
96     *
97     * @return The list as an array.
98     */
99    public CharSequence[] getEntries() {
100        return mEntries;
101    }
102
103    /**
104     * The array to find the value to save for a preference when an entry from
105     * entries is selected. If a user clicks on the second item in entries, the
106     * second item in this array will be saved to the preference.
107     *
108     * @param entryValues The array to be used as values to save for the preference.
109     */
110    public void setEntryValues(CharSequence[] entryValues) {
111        mEntryValues = entryValues;
112    }
113
114    /**
115     * @see #setEntryValues(CharSequence[])
116     * @param entryValuesResId The entry values array as a resource.
117     */
118    public void setEntryValues(int entryValuesResId) {
119        setEntryValues(getContext().getResources().getTextArray(entryValuesResId));
120    }
121
122    /**
123     * Returns the array of values to be saved for the preference.
124     *
125     * @return The array of values.
126     */
127    public CharSequence[] getEntryValues() {
128        return mEntryValues;
129    }
130
131    /**
132     * Sets the value of the key. This should contain entries in
133     * {@link #getEntryValues()}.
134     *
135     * @param values The values to set for the key.
136     */
137    public void setValues(Set<String> values) {
138        mValues.clear();
139        mValues.addAll(values);
140
141        persistStringSet(values);
142    }
143
144    /**
145     * Retrieves the current value of the key.
146     */
147    public Set<String> getValues() {
148        return mValues;
149    }
150
151    /**
152     * Returns the index of the given value (in the entry values array).
153     *
154     * @param value The value whose index should be returned.
155     * @return The index of the value, or -1 if not found.
156     */
157    public int findIndexOfValue(String value) {
158        if (value != null && mEntryValues != null) {
159            for (int i = mEntryValues.length - 1; i >= 0; i--) {
160                if (mEntryValues[i].equals(value)) {
161                    return i;
162                }
163            }
164        }
165        return -1;
166    }
167
168    @Override
169    protected void onPrepareDialogBuilder(Builder builder) {
170        super.onPrepareDialogBuilder(builder);
171
172        if (mEntries == null || mEntryValues == null) {
173            throw new IllegalStateException(
174                    "MultiSelectListPreference requires an entries array and " +
175                    "an entryValues array.");
176        }
177
178        boolean[] checkedItems = getSelectedItems();
179        builder.setMultiChoiceItems(mEntries, checkedItems,
180                new DialogInterface.OnMultiChoiceClickListener() {
181                    public void onClick(DialogInterface dialog, int which, boolean isChecked) {
182                        if (isChecked) {
183                            mPreferenceChanged |= mNewValues.add(mEntryValues[which].toString());
184                        } else {
185                            mPreferenceChanged |= mNewValues.remove(mEntryValues[which].toString());
186                        }
187                    }
188                });
189        mNewValues.clear();
190        mNewValues.addAll(mValues);
191    }
192
193    private boolean[] getSelectedItems() {
194        final CharSequence[] entries = mEntryValues;
195        final int entryCount = entries.length;
196        final Set<String> values = mValues;
197        boolean[] result = new boolean[entryCount];
198
199        for (int i = 0; i < entryCount; i++) {
200            result[i] = values.contains(entries[i].toString());
201        }
202
203        return result;
204    }
205
206    @Override
207    protected void onDialogClosed(boolean positiveResult) {
208        super.onDialogClosed(positiveResult);
209
210        if (positiveResult && mPreferenceChanged) {
211            final Set<String> values = mNewValues;
212            if (callChangeListener(values)) {
213                setValues(values);
214            }
215        }
216        mPreferenceChanged = false;
217    }
218
219    @Override
220    protected Object onGetDefaultValue(TypedArray a, int index) {
221        final CharSequence[] defaultValues = a.getTextArray(index);
222        final int valueCount = defaultValues.length;
223        final Set<String> result = new HashSet<String>();
224
225        for (int i = 0; i < valueCount; i++) {
226            result.add(defaultValues[i].toString());
227        }
228
229        return result;
230    }
231
232    @Override
233    protected void onSetInitialValue(boolean restoreValue, Object defaultValue) {
234        setValues(restoreValue ? getPersistedStringSet(mValues) : (Set<String>) defaultValue);
235    }
236
237    @Override
238    protected Parcelable onSaveInstanceState() {
239        final Parcelable superState = super.onSaveInstanceState();
240        if (isPersistent()) {
241            // No need to save instance state
242            return superState;
243        }
244
245        final SavedState myState = new SavedState(superState);
246        myState.values = getValues();
247        return myState;
248    }
249
250    private static class SavedState extends BaseSavedState {
251        Set<String> values;
252
253        public SavedState(Parcel source) {
254            super(source);
255            values = new HashSet<String>();
256            String[] strings = source.readStringArray();
257
258            final int stringCount = strings.length;
259            for (int i = 0; i < stringCount; i++) {
260                values.add(strings[i]);
261            }
262        }
263
264        public SavedState(Parcelable superState) {
265            super(superState);
266        }
267
268        @Override
269        public void writeToParcel(Parcel dest, int flags) {
270            super.writeToParcel(dest, flags);
271            dest.writeStringArray(values.toArray(new String[0]));
272        }
273
274        public static final Parcelable.Creator<SavedState> CREATOR =
275                new Parcelable.Creator<SavedState>() {
276            public SavedState createFromParcel(Parcel in) {
277                return new SavedState(in);
278            }
279
280            public SavedState[] newArray(int size) {
281                return new SavedState[size];
282            }
283        };
284    }
285}
286