96 lines
2.8 KiB
Java
96 lines
2.8 KiB
Java
package org.mian.gitnex.helpers;
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import android.view.View;
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import androidx.viewpager2.widget.ViewPager2;
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/**
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* @author M M Arif
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*/
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public abstract class ViewPager2Transformers {
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public static void returnSelectedTransformer(ViewPager2 viewPager, int selection) {
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if (selection == 0) {
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viewPager.setPageTransformer(new DepthPageTransformer());
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} else if (selection == 1) {
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viewPager.setPageTransformer(new ZoomOutPageTransformer());
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} else if (selection == 2) {
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viewPager.setPageTransformer(null);
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}
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}
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public static class DepthPageTransformer implements ViewPager2.PageTransformer {
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private static final float MIN_SCALE = 0.75f;
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public void transformPage(View view, float position) {
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int pageWidth = view.getWidth();
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if (position < -1) { // [-Infinity,-1)
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// This page is way off-screen to the left.
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view.setAlpha(0f);
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} else if (position <= 0) { // [-1,0]
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// Use the default slide transition when moving to the left page
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view.setAlpha(1f);
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view.setTranslationX(0f);
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view.setScaleX(1f);
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view.setScaleY(1f);
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} else if (position <= 1) { // (0,1]
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// Fade the page out.
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view.setAlpha(1 - position);
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// Counteract the default slide transition
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// view.setTranslationX(pageWidth * -position);
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// Scale the page down (between MIN_SCALE and 1)
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float scaleFactor = MIN_SCALE + (1 - MIN_SCALE) * (1 - Math.abs(position));
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view.setScaleX(scaleFactor);
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view.setScaleY(scaleFactor);
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} else { // (1,+Infinity]
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// This page is way off-screen to the right.
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view.setAlpha(0f);
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}
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}
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}
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public static class ZoomOutPageTransformer implements ViewPager2.PageTransformer {
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private static final float MIN_SCALE = 0.85f;
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private static final float MIN_ALPHA = 0.5f;
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public void transformPage(View view, float position) {
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int pageWidth = view.getWidth();
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int pageHeight = view.getHeight();
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if (position < -1) { // [-Infinity,-1)
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// This page is way off-screen to the left.
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view.setAlpha(0f);
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} else if (position <= 1) { // [-1,1]
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// Modify the default slide transition to shrink the page as well.
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float scaleFactor = Math.max(MIN_SCALE, 1 - Math.abs(position));
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float vertMargin = pageHeight * (1 - scaleFactor) / 2;
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float horzMargin = pageWidth * (1 - scaleFactor) / 2;
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if (position < 0) {
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view.setTranslationX(horzMargin - vertMargin / 2);
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} else {
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view.setTranslationX(-horzMargin + vertMargin / 2);
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}
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// Scale the page down (between MIN_SCALE and 1).
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view.setScaleX(scaleFactor);
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view.setScaleY(scaleFactor);
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// Fade the page relative to its size.
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view.setAlpha(
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MIN_ALPHA + (scaleFactor - MIN_SCALE) / (1 - MIN_SCALE) * (1 - MIN_ALPHA));
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} else { // (1,+Infinity]
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// This page is way off-screen to the right.
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view.setAlpha(0f);
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}
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}
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}
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}
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