Main.java Source code

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Here is the source code for Main.java

Source

//package com.java2s;
//License from project: Apache License 

import android.os.Build;

import android.view.View;
import android.view.ViewGroup;

public class Main {
    /**
     * Apply a parallax effect to a View/ViewGroup
     * @param view A View or ViewGroup
     * @param recursive Applies if {@code view} is a ViewGroup. If true, this will recursively go through any child ViewGroups and apply the effect to their children.
     *                  If false, only {@code view}'s immediate children will move in the parallax effect
     * @param offsetPixels The current pixel offset for the page {@code view} is on.
     * @param startParallaxFactor The speed at which the first child should move. Negative values for slower, positive for faster.
     * @param parallaxInterval The difference in speed between the children.
     */
    public static void applyParallaxEffect(View view, boolean recursive, int offsetPixels,
            float startParallaxFactor, float parallaxInterval) {
        if (recursive)
            applyParallaxEffectRecursively(view, offsetPixels, startParallaxFactor, parallaxInterval, 0);
        else
            applyParallaxEffectToImmediateChildren(view, offsetPixels, startParallaxFactor, parallaxInterval);
    }

    private static int applyParallaxEffectRecursively(View view, int offsetPixels, float startParallaxFactor,
            float parallaxInterval, int index) {
        int nextIndex = index;
        if (view instanceof ViewGroup) {
            ViewGroup group = (ViewGroup) view;
            for (int i = 0; i < group.getChildCount(); i++) {
                nextIndex = applyParallaxEffectRecursively(group.getChildAt(i), offsetPixels, startParallaxFactor,
                        parallaxInterval, nextIndex);
            }
        } else {
            translateViewForParallaxEffect(view, index, offsetPixels, startParallaxFactor, parallaxInterval);
            nextIndex++;
        }
        return nextIndex;
    }

    private static void applyParallaxEffectToImmediateChildren(View view, int offsetPixels,
            float startParallaxFactor, float parallaxInterval) {
        if (view instanceof ViewGroup) {
            ViewGroup group = (ViewGroup) view;
            for (int i = 0; i < group.getChildCount(); i++) {
                translateViewForParallaxEffect(group.getChildAt(i), i, offsetPixels, startParallaxFactor,
                        parallaxInterval);
            }
        } else {
            translateViewForParallaxEffect(view, 0, offsetPixels, startParallaxFactor, parallaxInterval);
        }
    }

    private static void translateViewForParallaxEffect(View view, int index, int offsetPixels,
            float startParallaxFactor, float parallaxInterval) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            view.setTranslationX(
                    calculateParallaxOffsetAmount(index, offsetPixels, startParallaxFactor, parallaxInterval));
        }
    }

    private static float calculateParallaxOffsetAmount(int index, int offsetPixels, float startParallaxFactor,
            float parallaxInterval) {
        return (startParallaxFactor + (index * parallaxInterval)) * -offsetPixels;
    }
}