先说下最近做应用市场，想要的效果如下：
1、上面actionbar使用的toolbar最新的工具条来代替acionbar.
2、toolbar下面有一个 app详情
3、app详情下面有一个滑动tab ，tab下是viewpage ，viewpage里面嵌套的是2个Fragment，，一个是Scrollview,一个是ListView。
要实现，监听Scrollview或者ListView滚动事件，来推挤tab向上移动，并且悬停在Toolbar下面。
具体效果如图：
代码不多解释，直接下载demo自行运行demo哈。稍后放源码。
声明：本代码基于其他开源项目，修改而来。
package com.github.ksoichiro.android.observablescrollview.samples;import android.os.Bundle;import android.support.v4.app.Fragment;import android.support.v4.app.FragmentManager;import android.support.v4.view.ViewCompat;import android.support.v4.view.ViewPager;import android.support.v7.app.ActionBarActivity;import android.support.v7.widget.Toolbar;import android.view.View;import com.example.toolbar.R;import com.github.ksoichiro.android.observablescrollview.ObservableScrollView;import com.github.ksoichiro.android.observablescrollview.ObservableScrollViewCallbacks;import com.github.ksoichiro.android.observablescrollview.ScrollState;import com.github.ksoichiro.android.observablescrollview.ScrollUtils;import com.google.samples.apps.iosched.ui.widget.SlidingTabLayout;import com.nineoldandroids.view.ViewHelper;import com.nineoldandroids.view.ViewPropertyAnimator;public class ViewPagerTabScrollViewActivity extends ActionBarActivity implements ObservableScrollViewCallbacks {private View mHeaderView;private View appinfo;private int mBaseTranslationY;private ViewPager mPager;private NavigationAdapter mPagerAdapter;private Toolbar toolbar;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_viewpagertab);toolbar=(Toolbar) findViewById(R.id.toolbar);setSupportActionBar(toolbar);mHeaderView = findViewById(R.id.header);ViewCompat.setElevation(mHeaderView, getResources().getDimension(R.dimen.toolbar_elevation));appinfo = findViewById(R.id.apptitleview);mPagerAdapter = new NavigationAdapter(getSupportFragmentManager());mPager = (ViewPager) findViewById(R.id.pager);mPager.setAdapter(mPagerAdapter);SlidingTabLayout slidingTabLayout = (SlidingTabLayout) 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);// When the page is selected, other fragments' scrollY should be adjusted// according to the toolbar status(shown/hidden)slidingTabLayout.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {@Overridepublic void onPageScrolled(int i, float v, int i2) {}@Overridepublic void onPageSelected(int i) {propagateToolbarState(toolbarIsShown());}@Overridepublic void onPageScrollStateChanged(int i) {}});propagateToolbarState(toolbarIsShown());}@Overridepublic void onScrollChanged(int scrollY, boolean firstScroll, boolean dragging) {//判断如果是拖动if (dragging) {int toolbarHeight = appinfo.getHeight();float currentHeaderTranslationY = ViewHelper.getTranslationY(mHeaderView);if (firstScroll) {if (-toolbarHeight < currentHeaderTranslationY) {mBaseTranslationY = scrollY;}}float headerTranslationY = ScrollUtils.getFloat(-(scrollY – mBaseTranslationY), -toolbarHeight, 0);ViewPropertyAnimator.animate(mHeaderView).cancel();ViewHelper.setTranslationY(mHeaderView, headerTranslationY);}else{if(!firstScroll){int toolbarHeight = appinfo.getHeight();float headerTranslationY = ScrollUtils.getFloat(-(scrollY – mBaseTranslationY), -toolbarHeight, 0);ViewPropertyAnimator.animate(mHeaderView).cancel();ViewHelper.setTranslationY(mHeaderView, headerTranslationY);}}}@Overridepublic void onDownMotionEvent() {}@Overridepublic void onUpOrCancelMotionEvent(ScrollState scrollState) {mBaseTranslationY = 0;Fragment fragment = getCurrentFragment();if (fragment == null) {return;}View view = fragment.getView();if (view == null) {return;}int toolbarHeight = appinfo.getHeight();final ObservableScrollView scrollView = (ObservableScrollView) view.findViewById(R.id.scroll);if (scrollView == null) {return;}int scrollY = scrollView.getCurrentScrollY();if (scrollState == ScrollState.DOWN) {//按下//判断滑动到顶部的时候，开始显示 toolbar 不是顶部的 隐藏toolbarif(scrollView.getScrollY()<=toolbarHeight){showToolbar();}else{hideToolbar();}} else if (scrollState == ScrollState.UP) {//抬起if (toolbarHeight <= scrollY) {hideToolbar();} else {showToolbar();}} else {//// Even if onScrollChanged occurs without scrollY changing, toolbar should be adjustedif (toolbarIsShown() || toolbarIsHidden()) {// Toolbar is completely moved, so just keep its state// and propagate it to other pagespropagateToolbarState(toolbarIsShown());} else {// 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 void propagateToolbarState(boolean isShown) {int toolbarHeight = appinfo.getHeight();//设置scrollY尚未创建的片段// Set scrollY for the fragments that are not created yetmPagerAdapter.setScrollY(isShown ? 0 : toolbarHeight);//设置活动scrollY碎片// Set scrollY for the active fragmentsfor (int i = 0; i < mPagerAdapter.getCount(); i++) {// Skip current itemif (i == mPager.getCurrentItem()) {continue;}// Skip destroyed or not created itemFragment f = mPagerAdapter.getItemAt(i);if (f == null) {continue;}ObservableScrollView scrollView = (ObservableScrollView) f.getView().findViewById(R.id.scroll);if (isShown) {// Scroll upif (0 < scrollView.getCurrentScrollY()) {//滚动到 顶部scrollView.scrollTo(0, 0);}} else {// Scroll down (to hide padding)//滚动到底部if (scrollView.getCurrentScrollY() < toolbarHeight) {scrollView.scrollTo(0, toolbarHeight);}}}}private boolean toolbarIsShown() {return ViewHelper.getTranslationY(mHeaderView) == 0;}private boolean toolbarIsHidden() {return ViewHelper.getTranslationY(mHeaderView) == -appinfo.getHeight();}private void showToolbar() {float headerTranslationY = ViewHelper.getTranslationY(mHeaderView);if (headerTranslationY != 0) {ViewPropertyAnimator.animate(mHeaderView).cancel();ViewPropertyAnimator.animate(mHeaderView).translationY(0).setDuration(200).start();}propagateToolbarState(true);}private void hideToolbar() {float headerTranslationY = ViewHelper.getTranslationY(mHeaderView);int toolbarHeight = appinfo.getHeight();if (headerTranslationY != -toolbarHeight) {ViewPropertyAnimator.animate(mHeaderView).cancel();ViewPropertyAnimator.animate(mHeaderView).translationY(-toolbarHeight).setDuration(200).start();}propagateToolbarState(false);}private static class NavigationAdapter extends CacheFragmentStatePagerAdapter {private static final String[] TITLES = new String[]{"Applepie", "Butter Cookie"};private int mScrollY;public NavigationAdapter(FragmentManager fm) {super(fm);}public void setScrollY(int scrollY) {mScrollY = scrollY;}@Overrideprotected Fragment createItem(int position) {Fragment f = new ViewPagerTabScrollViewFragment();if (0 <= mScrollY) {Bundle args = new Bundle();args.putInt(ViewPagerTabScrollViewFragment.ARG_SCROLL_Y, mScrollY);f.setArguments(args);}return f;}@Overridepublic int getCount() {return TITLES.length;}@Overridepublic CharSequence getPageTitle(int position) {return TITLES[position];}}}
可我，仍在旅行的路上徘徊。等待着每一辆经过的车，让我走到更远的地方。
