Java tutorial
/* * Copyright 2014 Soichiro Kashima * * 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.example.client.fragment.imported; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.view.ViewPager; import android.support.v7.app.AppCompatActivity; import android.view.LayoutInflater; import android.view.MotionEvent; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.widget.FrameLayout; import com.example.client.R; import com.github.ksoichiro.android.observablescrollview.CacheFragmentStatePagerAdapter; import com.github.ksoichiro.android.observablescrollview.ObservableScrollViewCallbacks; import com.github.ksoichiro.android.observablescrollview.ScrollState; import com.github.ksoichiro.android.observablescrollview.ScrollUtils; import com.github.ksoichiro.android.observablescrollview.Scrollable; import com.github.ksoichiro.android.observablescrollview.TouchInterceptionFrameLayout; import com.example.client.ui.widget.SlidingTabLayout; import com.nineoldandroids.animation.ValueAnimator; import com.nineoldandroids.view.ViewHelper; /** * This fragment manages ViewPager and its child Fragments. * Scrolling techniques are basically the same as ViewPagerTab2Activity. */ public class ViewPagerTabFragmentParentFragment extends ScrollFragment implements ObservableScrollViewCallbacks { public static final String FRAGMENT_TAG = "fragment"; private TouchInterceptionFrameLayout mInterceptionLayout; private ViewPager mPager; private NavigationAdapter mPagerAdapter; private int mSlop; private boolean mScrolled; private ScrollState mLastScrollState; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate(R.layout.fragment_viewpagertabfragment_parent, container, false); AppCompatActivity parentActivity = (AppCompatActivity) getActivity(); mPagerAdapter = new NavigationAdapter(getChildFragmentManager()); mPager = (ViewPager) view.findViewById(R.id.pager); mPager.setAdapter(mPagerAdapter); SlidingTabLayout slidingTabLayout = (SlidingTabLayout) view.findViewById(R.id.sliding_tabs); slidingTabLayout.setCustomTabView(R.layout.tab_indicator, android.R.id.text1); slidingTabLayout.setSelectedIndicatorColors(getResources().getColor(R.color.accent)); slidingTabLayout.setDistributeEvenly(true); slidingTabLayout.setViewPager(mPager); ViewConfiguration vc = ViewConfiguration.get(parentActivity); mSlop = vc.getScaledTouchSlop(); mInterceptionLayout = (TouchInterceptionFrameLayout) view.findViewById(R.id.container); mInterceptionLayout.setScrollInterceptionListener(mInterceptionListener); return view; } @Override public void onScrollChanged(int scrollY, boolean firstScroll, boolean dragging) { } @Override public void onDownMotionEvent() { } @Override public void onUpOrCancelMotionEvent(ScrollState scrollState) { if (!mScrolled) { // This event can be used only when TouchInterceptionFrameLayout // doesn't handle the consecutive events. adjustToolbar(scrollState); } } private TouchInterceptionFrameLayout.TouchInterceptionListener mInterceptionListener = new TouchInterceptionFrameLayout.TouchInterceptionListener() { @Override public boolean shouldInterceptTouchEvent(MotionEvent ev, boolean moving, float diffX, float diffY) { if (!mScrolled && mSlop < Math.abs(diffX) && Math.abs(diffY) < Math.abs(diffX)) { // Horizontal scroll is maybe handled by ViewPager return false; } Scrollable scrollable = getCurrentScrollable(); if (scrollable == null) { mScrolled = false; return false; } // If interceptionLayout can move, it should intercept. // And once it begins to move, horizontal scroll shouldn't work any longer. View toolbarView = getActivity().findViewById(R.id.toolbar); int toolbarHeight = toolbarView.getHeight(); int translationY = (int) ViewHelper.getTranslationY(mInterceptionLayout); boolean scrollingUp = 0 < diffY; boolean scrollingDown = diffY < 0; if (scrollingUp) { if (translationY < 0) { mScrolled = true; mLastScrollState = ScrollState.UP; return true; } } else if (scrollingDown) { if (-toolbarHeight < translationY) { mScrolled = true; mLastScrollState = ScrollState.DOWN; return true; } } mScrolled = false; return false; } @Override public void onDownMotionEvent(MotionEvent ev) { } @Override public void onMoveMotionEvent(MotionEvent ev, float diffX, float diffY) { View toolbarView = getActivity().findViewById(R.id.toolbar); float translationY = ScrollUtils.getFloat(ViewHelper.getTranslationY(mInterceptionLayout) + diffY, -toolbarView.getHeight(), 0); ViewHelper.setTranslationY(mInterceptionLayout, translationY); ViewHelper.setTranslationY(toolbarView, translationY); if (translationY < 0) { FrameLayout.LayoutParams lp = (FrameLayout.LayoutParams) mInterceptionLayout.getLayoutParams(); lp.height = (int) (-translationY + getScreenHeight()); mInterceptionLayout.requestLayout(); } } @Override public void onUpOrCancelMotionEvent(MotionEvent ev) { mScrolled = false; adjustToolbar(mLastScrollState); } }; private Scrollable getCurrentScrollable() { Fragment fragment = getCurrentFragment(); if (fragment == null) { return null; } View view = fragment.getView(); if (view == null) { return null; } return (Scrollable) view.findViewById(R.id.scroll); } private void adjustToolbar(ScrollState scrollState) { View toolbarView = getActivity().findViewById(R.id.toolbar); int toolbarHeight = toolbarView.getHeight(); final Scrollable scrollable = getCurrentScrollable(); if (scrollable == null) { return; } int scrollY = scrollable.getCurrentScrollY(); if (scrollState == ScrollState.DOWN) { showToolbar(); } else if (scrollState == ScrollState.UP) { if (toolbarHeight <= scrollY) { hideToolbar(); } else { showToolbar(); } } else if (!toolbarIsShown() && !toolbarIsHidden()) { // Toolbar is moving but doesn't know which to move: // you can change this to hideToolbar() showToolbar(); } } private Fragment getCurrentFragment() { return mPagerAdapter.getItemAt(mPager.getCurrentItem()); } private boolean toolbarIsShown() { return ViewHelper.getTranslationY(mInterceptionLayout) == 0; } private boolean toolbarIsHidden() { View view = getView(); if (view == null) { return false; } View toolbarView = getActivity().findViewById(R.id.toolbar); return ViewHelper.getTranslationY(mInterceptionLayout) == -toolbarView.getHeight(); } private void showToolbar() { animateToolbar(0); } private void hideToolbar() { View toolbarView = getActivity().findViewById(R.id.toolbar); animateToolbar(-toolbarView.getHeight()); } private void animateToolbar(final float toY) { float layoutTranslationY = ViewHelper.getTranslationY(mInterceptionLayout); if (layoutTranslationY != toY) { ValueAnimator animator = ValueAnimator.ofFloat(ViewHelper.getTranslationY(mInterceptionLayout), toY) .setDuration(200); animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { float translationY = (float) animation.getAnimatedValue(); View toolbarView = getActivity().findViewById(R.id.toolbar); ViewHelper.setTranslationY(mInterceptionLayout, translationY); ViewHelper.setTranslationY(toolbarView, translationY); if (translationY < 0) { FrameLayout.LayoutParams lp = (FrameLayout.LayoutParams) mInterceptionLayout .getLayoutParams(); lp.height = (int) (-translationY + getScreenHeight()); mInterceptionLayout.requestLayout(); } } }); animator.start(); } } /** * This adapter provides two types of fragments as an example. * {@linkplain #createItem(int)} should be modified if you use this example for your app. */ private static class NavigationAdapter extends CacheFragmentStatePagerAdapter { private static final String[] TITLES = new String[] { "Applepie", "Butter Cookie", "Cupcake", "Donut", "Eclair", "Froyo", "Gingerbread", "Honeycomb", "Ice Cream Sandwich", "Jelly Bean", "KitKat", "Lollipop" }; public NavigationAdapter(FragmentManager fm) { super(fm); } @Override protected Fragment createItem(int position) { Fragment f; final int pattern = position % 5; switch (pattern) { case 0: f = new ViewPagerTabFragmentScrollViewFragment(); break; case 1: f = new ViewPagerTabFragmentListViewFragment(); break; case 2: f = new ViewPagerTabFragmentRecyclerViewFragment(); break; case 3: f = new ViewPagerTabFragmentGridViewFragment(); break; case 4: default: f = new ViewPagerTabFragmentWebViewFragment(); break; } return f; } @Override public int getCount() { return TITLES.length; } @Override public CharSequence getPageTitle(int position) { return TITLES[position]; } } }