LatinIME/java/src/com/android/inputmethod/compat/SuggestionSpanUtils.java

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.inputmethod.compat;

import com.android.inputmethod.latin.SuggestedWords;
import com.android.inputmethod.latin.SuggestionSpanPickedNotificationReceiver;

import android.content.Context;
import android.text.Spannable;
import android.text.SpannableString;
import android.text.Spanned;

import java.lang.reflect.Constructor;
import java.util.Locale;

public class SuggestionSpanUtils {
    public static final String ACTION_SUGGESTION_PICKED =
            "android.text.style.SUGGESTION_PICKED";
    public static final String SUGGESTION_SPAN_PICKED_AFTER = "after";
    public static final String SUGGESTION_SPAN_PICKED_BEFORE = "before";
    public static final String SUGGESTION_SPAN_PICKED_HASHCODE = "hashcode";

    private static final Class<?> CLASS_SuggestionSpan = CompatUtils
            .getClass("android.text.style.SuggestionSpan");
    private static final Class<?>[] INPUT_TYPE_SuggestionSpan = new Class<?>[] {
            Context.class, Locale.class, String[].class, int.class, Class.class };
    private static final Constructor<?> CONSTRUCTOR_SuggestionSpan = CompatUtils
            .getConstructor(CLASS_SuggestionSpan, INPUT_TYPE_SuggestionSpan);
    public static final boolean SUGGESTION_SPAN_IS_SUPPORTED;
    static {
        SUGGESTION_SPAN_IS_SUPPORTED =
                CLASS_SuggestionSpan != null && CONSTRUCTOR_SuggestionSpan != null;
    }

    public static CharSequence getTextWithSuggestionSpan(Context context,
            CharSequence suggestion, SuggestedWords suggestedWords) {
        if (CONSTRUCTOR_SuggestionSpan == null || suggestedWords == null
                || suggestedWords.size() == 0) {
            return suggestion;
        }

        final Spannable spannable;
        if (suggestion instanceof Spannable) {
            spannable = (Spannable) suggestion;
        } else {
            spannable = new SpannableString(suggestion);
        }
        // TODO: Use SUGGESTIONS_MAX_SIZE instead of 5.
        final int N = Math.min(5, suggestedWords.size());
        final String[] suggestionsArray = new String[N];
        for (int i = 0; i < N; ++i) {
            suggestionsArray[i] = suggestedWords.getWord(i).toString();
        }
        final Object[] args =
                { context, null, suggestionsArray, 0,
                        (Class<?>) SuggestionSpanPickedNotificationReceiver.class };
        final Object ss = CompatUtils.newInstance(CONSTRUCTOR_SuggestionSpan, args);
        if (ss == null) {
            return suggestion;
        }
        spannable.setSpan(ss, 0, suggestion.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
        return spannable;
    }
}