Java tutorial
/* * The MIT License (MIT) * * Copyright (c) 2015 Cleveroad * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ package com.cleveroad.slidingtutorial; import android.animation.ArgbEvaluator; import android.os.Bundle; import android.support.annotation.ColorInt; import android.support.annotation.IdRes; import android.support.annotation.LayoutRes; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentPagerAdapter; import android.support.v4.view.ViewPager; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import java.util.Collections; import java.util.List; /** * Base Fragment that contains {@link ViewPager} and where happen most logic like dispatching * transform event to child fragment, changing background color, and located page indicator witch * associated with {@link ViewPagerWrapper}. */ public abstract class PresentationPagerFragment extends Fragment implements ViewPager.OnPageChangeListener, View.OnClickListener { private ViewPager viewPager; private View bSkip; private View separator; private CirclePageIndicator indicator; private ArgbEvaluator argbEvaluator = new ArgbEvaluator(); public PresentationPagerFragment() { } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setRetainInstance(true); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate(getLayoutResId(), container, false); viewPager = (ViewPager) view.findViewById(getViewPagerResId()); indicator = (CirclePageIndicator) view.findViewById(getIndicatorResId()); bSkip = view.findViewById(getButtonSkipResId()); separator = view.findViewById(getSeparatorResId()); return view; } @Override public void onViewCreated(View view, Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); viewPager.setAdapter(new PresentationAdapter(getChildFragmentManager())); if (isInfiniteScrollEnabled()) { int pos = Integer.MAX_VALUE / 2; pos -= pos % getPagesCount(); viewPager.setCurrentItem(pos); } indicator.setViewPager(new ViewPagerWrapper(getContext(), viewPager), getPagesCount()); viewPager.addOnPageChangeListener(this); viewPager.setPageTransformer(true, new FragmentTransformer()); bSkip.setOnClickListener(this); } @Override public void onClick(View v) { if (v.getId() == getButtonSkipResId()) { if (!onSkipButtonClicked(v)) { removeFragmentFromScreen(); } } } /** * Get line separator view. * @return line separator view */ public View getSeparator() { return separator; } /** * Get view pager. * @return view pager */ public ViewPager getViewPager() { return viewPager; } /** * Get skip button. * @return skip button */ public View getSkipButton() { return bSkip; } /** * Get view pager indicator. * @return view pager indicator */ public CirclePageIndicator getPagerIndicator() { return indicator; } /** * According to position and positionOffset changing background color. If last position then * change root view alpha. */ @SuppressWarnings("ConstantConditions") @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { if (isInfiniteScrollEnabled() && getPagesCount() != 0) { position %= getPagesCount(); } int nextColorPosition = position + 1; if (nextColorPosition >= getPagesCount()) { nextColorPosition %= getPagesCount(); } if (position < (viewPager.getAdapter().getCount() - 1)) { viewPager.setBackgroundColor((Integer) argbEvaluator.evaluate(positionOffset, getPageColor(position), getPageColor(nextColorPosition))); } else if (!isInfiniteScrollEnabled() && position == getPagesCount() - 1) { viewPager.setBackgroundColor(getPageColor(position)); if (getView() != null) { getView().setAlpha(1 - positionOffset); } } } /** * When last position will be reached then remove fragment from the screen. */ @Override public void onPageSelected(int position) { if (!isInfiniteScrollEnabled() && position == getPagesCount()) { removeFragmentFromScreen(); } } @Override public void onPageScrollStateChanged(int state) { } private void removeFragmentFromScreen() { getActivity().getSupportFragmentManager().beginTransaction().remove(PresentationPagerFragment.this) .commitAllowingStateLoss(); } /** * Obtain custom page fragment list for presentation view pager. * * @return list of custom page fragments. */ @Deprecated protected List<? extends PageFragment> getPageFragments() { return Collections.emptyList(); } @LayoutRes protected abstract int getLayoutResId(); @IdRes protected abstract int getViewPagerResId(); @IdRes protected abstract int getIndicatorResId(); @IdRes protected abstract int getButtonSkipResId(); @IdRes protected abstract int getSeparatorResId(); /** * Enable or disable infinite scroll. Default value is false. * * @return true to enable infinite scroll, false otherwise. */ protected boolean isInfiniteScrollEnabled() { return false; } /** * Get total pages count. * * @return pages count */ protected abstract int getPagesCount(); /** * Get specific page by position index. * * @param position index of page * @return page at specified position */ protected abstract PageFragment getPage(int position); /** * Get page color. * * @param position index of page * @return color of page */ @ColorInt protected abstract int getPageColor(int position); /** * Called when user pressed Skip button. Default behavior: remove presentation fragment. * @param skipButton skip button * @return true if you consumed click listener and implemented your own behavior, false otherwise */ protected boolean onSkipButtonClicked(View skipButton) { return false; } /** * Implementation of {@link FragmentPagerAdapter} that in addition add empty last fragment. */ private class PresentationAdapter extends FragmentPagerAdapter { private final Fragment emptyFragment = new Fragment(); public PresentationAdapter(FragmentManager fm) { super(fm); } @Override public Fragment getItem(int position) { if (isInfiniteScrollEnabled()) { position %= getPagesCount(); } if (position < getPagesCount()) { return getPage(position); } else if (position == getPagesCount()) { return emptyFragment; } else { throw new IllegalArgumentException("Invalid position: " + position); } } @Override public int getCount() { if (getPagesCount() == 0) return 0; if (isInfiniteScrollEnabled()) return Integer.MAX_VALUE; return getPagesCount() + 1; } } /** * Implementation of {@link android.support.v4.view.ViewPager.PageTransformer} that dispatch * transform page event whenever a visible/attached page is scrolled. */ private class FragmentTransformer implements ViewPager.PageTransformer { public void transformPage(View view, float position) { Object obj = view.getTag(R.id.st_page_fragment); if (obj instanceof PageFragment) { ((PageFragment) obj).transformPage(view, position); } } } }