LocaleSpan.java revision 4037d51b132a85dcfe37a95f9d2d91ad23d162fd 
1/*
2 * Copyright (C) 2012 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.text.style;
18
19import android.annotation.NonNull;
20import android.annotation.Nullable;
21import android.graphics.Paint;
22import android.os.LocaleList;
23import android.os.Parcel;
24import android.text.ParcelableSpan;
25import android.text.TextPaint;
26import android.text.TextUtils;
27
28import com.android.internal.util.Preconditions;
29
30import java.util.Locale;
31
32/**
33 * Changes the {@link Locale} of the text to which the span is attached.
34 */
35public class LocaleSpan extends MetricAffectingSpan implements ParcelableSpan {
36    @NonNull
37    private final LocaleList mLocales;
38
39    /**
40     * Creates a {@link LocaleSpan} from a well-formed {@link Locale}.  Note that only
41     * {@link Locale} objects that can be created by {@link Locale#forLanguageTag(String)} are
42     * supported.
43     *
44     * <p><b>Caveat:</b> Do not specify any {@link Locale} object that cannot be created by
45     * {@link Locale#forLanguageTag(String)}.  {@code new Locale(" a ", " b c", " d")} is an
46     * example of such a malformed {@link Locale} object.</p>
47     *
48     * @param locale The {@link Locale} of the text to which the span is attached.
49     *
50     * @see #LocaleSpan(LocaleList)
51     */
52    public LocaleSpan(@Nullable Locale locale) {
53        mLocales = locale == null ? LocaleList.getEmptyLocaleList() : new LocaleList(locale);
54    }
55
56    /**
57     * Creates a {@link LocaleSpan} from {@link LocaleList}.
58     *
59     * @param locales The {@link LocaleList} of the text to which the span is attached.
60     * @throws NullPointerException if {@code locales} is null
61     */
62    public LocaleSpan(@NonNull LocaleList locales) {
63        Preconditions.checkNotNull(locales, "locales cannot be null");
64        mLocales = locales;
65    }
66
67    public LocaleSpan(Parcel source) {
68        mLocales = LocaleList.CREATOR.createFromParcel(source);
69    }
70
71    @Override
72    public int getSpanTypeId() {
73        return getSpanTypeIdInternal();
74    }
75
76    /** @hide */
77    public int getSpanTypeIdInternal() {
78        return TextUtils.LOCALE_SPAN;
79    }
80
81    @Override
82    public int describeContents() {
83        return 0;
84    }
85
86    @Override
87    public void writeToParcel(Parcel dest, int flags) {
88        writeToParcelInternal(dest, flags);
89    }
90
91    /** @hide */
92    public void writeToParcelInternal(Parcel dest, int flags) {
93        mLocales.writeToParcel(dest, flags);
94    }
95
96    /**
97     * @return The {@link Locale} for this span.  If multiple locales are associated with this
98     * span, only the first locale is returned.  {@code null} if no {@link Locale} is specified.
99     *
100     * @see LocaleList#get()
101     * @see #getLocales()
102     */
103    @Nullable
104    public Locale getLocale() {
105        return mLocales.get(0);
106    }
107
108    /**
109     * @return The entire list of locales that are associated with this span.
110     */
111    @NonNull
112    public LocaleList getLocales() {
113        return mLocales;
114    }
115
116    @Override
117    public void updateDrawState(TextPaint ds) {
118        apply(ds, mLocales);
119    }
120
121    @Override
122    public void updateMeasureState(TextPaint paint) {
123        apply(paint, mLocales);
124    }
125
126    private static void apply(@NonNull Paint paint, @NonNull LocaleList locales) {
127        paint.setTextLocales(locales);
128    }
129}
130