pl.hypeapp.wykopolka.extra.pagetransformer.BaseTransformer.java Source code

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Here is the source code for pl.hypeapp.wykopolka.extra.pagetransformer.BaseTransformer.java

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/*
 * Copyright 2014 Toxic Bakery
 *
 * 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 pl.hypeapp.wykopolka.extra.pagetransformer;

import android.support.v4.view.ViewPager;
import android.view.View;

public abstract class BaseTransformer implements ViewPager.PageTransformer {

    /**
     * Called each {@link #transformPage(android.view.View, float)}.
     *
     * @param view
     * @param position
     */
    protected abstract void onTransform(View view, float position);

    @Override
    public void transformPage(View view, float position) {
        onPreTransform(view, position);
        onTransform(view, position);
        onPostTransform(view, position);
    }

    /**
     * If the position offset of a fragment is less than negative one or greater than one, returning true will set the
     * visibility of the fragment to {@link android.view.View#GONE}. Returning false will force the fragment to {@link android.view.View#VISIBLE}.
     *
     * @return
     */
    protected boolean hideOffscreenPages() {
        return true;
    }

    /**
     * Indicates if the default animations of the view pager should be used.
     *
     * @return
     */
    protected boolean isPagingEnabled() {
        return false;
    }

    /**
     * Called each {@link #transformPage(android.view.View, float)} before {{@link #onTransform(android.view.View, float)} is called.
     *
     * @param view
     * @param position
     */
    protected void onPreTransform(View view, float position) {
        final float width = view.getWidth();

        view.setRotationX(0);
        view.setRotationY(0);
        view.setRotation(0);
        view.setScaleX(1);
        view.setScaleY(1);
        view.setPivotX(0);
        view.setPivotY(0);
        view.setTranslationY(0);
        if (isPagingEnabled())
            view.setTranslationX(0f);
        else
            view.setTranslationX(-width * position);

        if (hideOffscreenPages()) {
            view.setAlpha(position <= -1f || position >= 1f ? 0f : 1f);
        } else {
            view.setAlpha(1f);
        }
    }

    /**
     * Called each {@link #transformPage(android.view.View, float)} call after {@link #onTransform(android.view.View, float)} is finished.
     *
     * @param view
     * @param position
     */
    protected void onPostTransform(View view, float position) {
    }

}