1/*
2 * Copyright (C) 2015 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.support.v7.preference;
18
19import android.content.Context;
20import android.content.res.TypedArray;
21import android.os.Parcel;
22import android.os.Parcelable;
23import android.support.annotation.RestrictTo;
24import android.text.TextUtils;
25import android.util.AttributeSet;
26import android.view.View;
27import android.widget.TextView;
28
29import static android.support.annotation.RestrictTo.Scope.GROUP_ID;
30
31/**
32 * Common base class for preferences that have two selectable states, persist a
33 * boolean value in SharedPreferences, and may have dependent preferences that are
34 * enabled/disabled based on the current state.
35 */
36public abstract class TwoStatePreference extends Preference {
37
38    private CharSequence mSummaryOn;
39    private CharSequence mSummaryOff;
40    protected boolean mChecked;
41    private boolean mCheckedSet;
42    private boolean mDisableDependentsState;
43
44    public TwoStatePreference(
45            Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
46        super(context, attrs, defStyleAttr, defStyleRes);
47    }
48
49    public TwoStatePreference(Context context, AttributeSet attrs, int defStyleAttr) {
50        this(context, attrs, defStyleAttr, 0);
51    }
52
53    public TwoStatePreference(Context context, AttributeSet attrs) {
54        this(context, attrs, 0);
55    }
56
57    public TwoStatePreference(Context context) {
58        this(context, null);
59    }
60
61    @Override
62    protected void onClick() {
63        super.onClick();
64
65        final boolean newValue = !isChecked();
66        if (callChangeListener(newValue)) {
67            setChecked(newValue);
68        }
69    }
70
71    /**
72     * Sets the checked state and saves it to the {@link android.content.SharedPreferences}.
73     *
74     * @param checked The checked state.
75     */
76    public void setChecked(boolean checked) {
77        // Always persist/notify the first time; don't assume the field's default of false.
78        final boolean changed = mChecked != checked;
79        if (changed || !mCheckedSet) {
80            mChecked = checked;
81            mCheckedSet = true;
82            persistBoolean(checked);
83            if (changed) {
84                notifyDependencyChange(shouldDisableDependents());
85                notifyChanged();
86            }
87        }
88    }
89
90    /**
91     * Returns the checked state.
92     *
93     * @return The checked state.
94     */
95    public boolean isChecked() {
96        return mChecked;
97    }
98
99    @Override
100    public boolean shouldDisableDependents() {
101        boolean shouldDisable = mDisableDependentsState ? mChecked : !mChecked;
102        return shouldDisable || super.shouldDisableDependents();
103    }
104
105    /**
106     * Sets the summary to be shown when checked.
107     *
108     * @param summary The summary to be shown when checked.
109     */
110    public void setSummaryOn(CharSequence summary) {
111        mSummaryOn = summary;
112        if (isChecked()) {
113            notifyChanged();
114        }
115    }
116
117    /**
118     * @see #setSummaryOn(CharSequence)
119     * @param summaryResId The summary as a resource.
120     */
121    public void setSummaryOn(int summaryResId) {
122        setSummaryOn(getContext().getString(summaryResId));
123    }
124
125    /**
126     * Returns the summary to be shown when checked.
127     * @return The summary.
128     */
129    public CharSequence getSummaryOn() {
130        return mSummaryOn;
131    }
132
133    /**
134     * Sets the summary to be shown when unchecked.
135     *
136     * @param summary The summary to be shown when unchecked.
137     */
138    public void setSummaryOff(CharSequence summary) {
139        mSummaryOff = summary;
140        if (!isChecked()) {
141            notifyChanged();
142        }
143    }
144
145    /**
146     * @see #setSummaryOff(CharSequence)
147     * @param summaryResId The summary as a resource.
148     */
149    public void setSummaryOff(int summaryResId) {
150        setSummaryOff(getContext().getString(summaryResId));
151    }
152
153    /**
154     * Returns the summary to be shown when unchecked.
155     * @return The summary.
156     */
157    public CharSequence getSummaryOff() {
158        return mSummaryOff;
159    }
160
161    /**
162     * Returns whether dependents are disabled when this preference is on ({@code true})
163     * or when this preference is off ({@code false}).
164     *
165     * @return Whether dependents are disabled when this preference is on ({@code true})
166     *         or when this preference is off ({@code false}).
167     */
168    public boolean getDisableDependentsState() {
169        return mDisableDependentsState;
170    }
171
172    /**
173     * Sets whether dependents are disabled when this preference is on ({@code true})
174     * or when this preference is off ({@code false}).
175     *
176     * @param disableDependentsState The preference state that should disable dependents.
177     */
178    public void setDisableDependentsState(boolean disableDependentsState) {
179        mDisableDependentsState = disableDependentsState;
180    }
181
182    @Override
183    protected Object onGetDefaultValue(TypedArray a, int index) {
184        return a.getBoolean(index, false);
185    }
186
187    @Override
188    protected void onSetInitialValue(boolean restoreValue, Object defaultValue) {
189        setChecked(restoreValue ? getPersistedBoolean(mChecked)
190                : (Boolean) defaultValue);
191    }
192
193    /**
194     * Sync a summary holder contained within holder's subhierarchy with the correct summary text.
195     * @param holder PreferenceViewHolder which holds a reference to the summary view
196     */
197    protected void syncSummaryView(PreferenceViewHolder holder) {
198        // Sync the summary holder
199        View view = holder.findViewById(android.R.id.summary);
200        syncSummaryView(view);
201    }
202
203    /**
204     * @hide
205     */
206    @RestrictTo(GROUP_ID)
207    protected void syncSummaryView(View view) {
208        if (!(view instanceof TextView)) {
209            return;
210        }
211        TextView summaryView = (TextView) view;
212        boolean useDefaultSummary = true;
213        if (mChecked && !TextUtils.isEmpty(mSummaryOn)) {
214            summaryView.setText(mSummaryOn);
215            useDefaultSummary = false;
216        } else if (!mChecked && !TextUtils.isEmpty(mSummaryOff)) {
217            summaryView.setText(mSummaryOff);
218            useDefaultSummary = false;
219        }
220        if (useDefaultSummary) {
221            final CharSequence summary = getSummary();
222            if (!TextUtils.isEmpty(summary)) {
223                summaryView.setText(summary);
224                useDefaultSummary = false;
225            }
226        }
227        int newVisibility = View.GONE;
228        if (!useDefaultSummary) {
229            // Someone has written to it
230            newVisibility = View.VISIBLE;
231        }
232        if (newVisibility != summaryView.getVisibility()) {
233            summaryView.setVisibility(newVisibility);
234        }
235    }
236
237    @Override
238    protected Parcelable onSaveInstanceState() {
239        final Parcelable superState = super.onSaveInstanceState();
240        if (isPersistent()) {
241            // No need to save instance state since it's persistent
242            return superState;
243        }
244
245        final SavedState myState = new SavedState(superState);
246        myState.checked = isChecked();
247        return myState;
248    }
249
250    @Override
251    protected void onRestoreInstanceState(Parcelable state) {
252        if (state == null || !state.getClass().equals(SavedState.class)) {
253            // Didn't save state for us in onSaveInstanceState
254            super.onRestoreInstanceState(state);
255            return;
256        }
257
258        SavedState myState = (SavedState) state;
259        super.onRestoreInstanceState(myState.getSuperState());
260        setChecked(myState.checked);
261    }
262
263    static class SavedState extends BaseSavedState {
264        boolean checked;
265
266        public SavedState(Parcel source) {
267            super(source);
268            checked = source.readInt() == 1;
269        }
270
271        @Override
272        public void writeToParcel(Parcel dest, int flags) {
273            super.writeToParcel(dest, flags);
274            dest.writeInt(checked ? 1 : 0);
275        }
276
277        public SavedState(Parcelable superState) {
278            super(superState);
279        }
280
281        public static final Parcelable.Creator<SavedState> CREATOR =
282                new Parcelable.Creator<SavedState>() {
283            @Override
284            public SavedState createFromParcel(Parcel in) {
285                return new SavedState(in);
286            }
287
288            @Override
289            public SavedState[] newArray(int size) {
290                return new SavedState[size];
291            }
292        };
293    }
294}
295