am 413aded6: Add a compatibility library for newly added methods in L

/*

 * Copyright (C) 2014 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 android.view.inputmethod.InputConnection;

import java.lang.reflect.Constructor;

import java.lang.reflect.Method;

public final class InputConnectionCompatUtils {

    // Note that CursorAnchorInfoRequest is supposed to be available in API level 21 and later.

    private static Class<?> getCursorAnchorInfoRequestClass() {

        try {

            return Class.forName("android.view.inputmethod.CursorAnchorInfoRequest");

        } catch (ClassNotFoundException e) {

            return null;

        }

    }

    private static final Class<?> TYPE_CursorAnchorInfoRequest;

    private static final Constructor<?> CONSTRUCTOR_CursorAnchorInfoRequest;

    private static final Method METHOD_requestCursorAnchorInfo;

    static {

        TYPE_CursorAnchorInfoRequest = getCursorAnchorInfoRequestClass();

        CONSTRUCTOR_CursorAnchorInfoRequest = CompatUtils.getConstructor(

                TYPE_CursorAnchorInfoRequest, int.class, int.class);

        METHOD_requestCursorAnchorInfo = CompatUtils.getMethod(InputConnection.class,

                "requestCursorAnchorInfo", TYPE_CursorAnchorInfoRequest);

    }

    public static boolean isRequestCursorAnchorInfoAvailable() {

        return METHOD_requestCursorAnchorInfo != null &&

                CONSTRUCTOR_CursorAnchorInfoRequest != null;

    }

    /**

     * A local copy of CursorAnchorInfoRequest.RESULT_NOT_HANDLED until the SDK becomes publicly

     * available.

     */

    private final static int CURSOR_ANCHOR_INFO_REQUEST_RESULT_NOT_HANDLED = 0;

    public static int requestCursorAnchorInfo(final InputConnection inputConnection,

            final int type, final int flags) {

        if (!isRequestCursorAnchorInfoAvailable()) {

             return CURSOR_ANCHOR_INFO_REQUEST_RESULT_NOT_HANDLED;

        }

        final Object requestObject = CompatUtils.newInstance(

                CONSTRUCTOR_CursorAnchorInfoRequest, type, flags);

        if (requestObject == null) {

            return CURSOR_ANCHOR_INFO_REQUEST_RESULT_NOT_HANDLED;

        }

        return (Integer) CompatUtils.invoke(inputConnection,

                CURSOR_ANCHOR_INFO_REQUEST_RESULT_NOT_HANDLED /* defaultValue */,

                METHOD_requestCursorAnchorInfo, requestObject);

    }

}