Android scrollView和viewpager嵌套 指示器吸顶 根据viewpager每

Android scrollView和viewpager嵌套 指示器吸顶 根据viewpager每个页面的内容适配高度

这几天 朋友问我了个问题  有个特别的需求  页面如下

就是当viewpager里面的当前页面内容足够多的时候  要去能滑上去 并且指示器吸顶  但是当内容不多的时候  能滑到哪就停在哪  当时第一反应是用coordinatelayout  结果不行 内容少的时候  也直接滑到顶部了

activity的xml文件

后来就直接用scrollView包裹来实现了 自定义scrollView实现滚动监听 用来实现指示器吸顶效果

public classMyScrollview extendsScrollView {

privateScrollViewListener scrollViewListener= null;publicMyScrollview(Context context) {

super(context);}

publicMyScrollview(Context context,AttributeSet attrs) {

super(context,attrs);}

publicMyScrollview(Context context,AttributeSet attrs, intdefStyleAttr) {

super(context,attrs,defStyleAttr);}

public voidsetScrollViewListener(ScrollViewListener scrollViewListener) {

this.scrollViewListener= scrollViewListener;}

@Overrideprotected voidonScrollChanged(intl, intt, intoldl, intoldt) {

super.onScrollChanged(l,t,oldl,oldt);if(scrollViewListener!= null) {

scrollViewListener.onScrollChanged(this,l,t,oldl,oldt);}

}

public interfaceScrollViewListener {

voidonScrollChanged(MyScrollview scrollView, intl, intt, intoldl, intoldt);}

}

在activity里面设置监听

scroll.setScrollViewListener(newMyScrollview.ScrollViewListener() {

@Overridepublic voidonScrollChanged(MyScrollview scrollView, intl, intt, intoldl, intoldt) {

if(t >iv.getHeight() && mTabLayout.getParent() == layout) {

layout.removeView(mTabLayout);rl_layout.addView(mTabLayout);} else if(t < iv.getHeight() && mTabLayout.getParent() == rl_layout) {

rl_layout.removeView(mTabLayout);layout.addView(mTabLayout);}

}

});

然后就是实现viewpager的每个页面的内容高度适配了  从写viewpager

public classCustomViewPager extendsViewPager {

private intcurrent;private intheight= 0;/*** 保存position与对于的View*/privateHashMap mChildrenViews= newLinkedHashMap();private booleanscrollble= true;publicCustomViewPager(Context context) {

super(context);}

publicCustomViewPager(Context context,AttributeSet attrs) {

super(context,attrs);}

@Overrideprotected voidonMeasure(intwidthMeasureSpec, intheightMeasureSpec) {

if(mChildrenViews.size() > current) {

View child = mChildrenViews.get(current);if(child != null) {

child.measure(widthMeasureSpec,MeasureSpec.makeMeasureSpec(0,MeasureSpec.UNSPECIFIED));height= child.getMeasuredHeight();}

}

heightMeasureSpec = MeasureSpec.makeMeasureSpec(height,MeasureSpec.EXACTLY);super.onMeasure(widthMeasureSpec,heightMeasureSpec);}

public voidresetHeight(intcurrent) {

this.current= current;if(mChildrenViews.size() > current) {

LinearLayout.LayoutParams layoutParams = (LinearLayout.LayoutParams) getLayoutParams();if(layoutParams == null) {

layoutParams = newLinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,height);} else{

layoutParams.height= height;}

setLayoutParams(layoutParams);}

}

/*** 保存position与对于的View*/public voidsetObjectForPosition(View view, intposition) {

mChildrenViews.put(position,view);}

@Overridepublic booleanonTouchEvent(MotionEvent ev) {

if(!scrollble) {

return true;}

return super.onTouchEvent(ev);}

public booleanisScrollble() {

returnscrollble;}

public voidsetScrollble(booleanscrollble) {

this.scrollble= scrollble;}

}用法是在每个fragment 的onCreatView里面添加一行代码就行

然后在viewpager所在的activity里面设置监听  就可以了

mViewPager.setOnPageChangeListener(newViewPager.OnPageChangeListener() {

@Overridepublic voidonPageScrolled(intposition, floatpositionOffset, intpositionOffsetPixels) {

}

@Overridepublic voidonPageSelected(intposition) {

mViewPager.resetHeight(position);}

@Overridepublic voidonPageScrollStateChanged(intstate) {

}

});

下面是整个activity的代码

packagecom.example.wenlaisu.myapplication;importandroid.os.Bundle;importandroid.support.design.widget.TabLayout;importandroid.support.v4.app.Fragment;importandroid.support.v4.view.ViewPager;importandroid.support.v7.app.AppCompatActivity;importandroid.widget.ImageView;importandroid.widget.LinearLayout;importandroid.widget.RelativeLayout;importjava.util.ArrayList;importjava.util.List;/*** Created by wenlaisu on 2018/4/12.*/public classViewPagerSample extendsAppCompatActivity {

CustomViewPager mViewPager;List mFragments;String[] mTitles= newString[]{

"主页","微博","相册"};privateTabLayout mTabLayout;privateMyScrollview scroll;privateLinearLayout layout;privateRelativeLayout rl_layout;privateImageView iv;@Overrideprotected voidonCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);setContentView(R.layout.activity_third);// 第一步，初始化ViewPager和TabLayoutmViewPager= (CustomViewPager) findViewById(R.id.viewpager);mTabLayout= (TabLayout) findViewById(R.id.tabs);layout= (LinearLayout) findViewById(R.id.layout);rl_layout= (RelativeLayout) findViewById(R.id.rl_layout);scroll= (MyScrollview) findViewById(R.id.scroll);iv= (ImageView) findViewById(R.id.iv);setupViewPager();}

private voidsetupViewPager() {

mFragments= newArrayList<>();ListFragment listFragment = newListFragment(mViewPager,0);ListFragment2 listFragment2 = newListFragment2(mViewPager,1);ListFragment3 listFragment3 = newListFragment3(mViewPager,2);mFragments.add(listFragment);mFragments.add(listFragment2);mFragments.add(listFragment3);// 第二步：为ViewPager设置适配器BaseFragmentAdapter adapter =

newBaseFragmentAdapter(getSupportFragmentManager(),mFragments,mTitles);mViewPager.setAdapter(adapter);// 第三步：将ViewPager与TableLayout 绑定在一起mTabLayout.setupWithViewPager(mViewPager);mViewPager.setOnPageChangeListener(newViewPager.OnPageChangeListener() {

@Overridepublic voidonPageScrolled(intposition, floatpositionOffset, intpositionOffsetPixels) {

}

@Overridepublic voidonPageSelected(intposition) {

mViewPager.resetHeight(position);}

@Overridepublic voidonPageScrollStateChanged(intstate) {

}

});scroll.setScrollViewListener(newMyScrollview.ScrollViewListener() {

@Overridepublic voidonScrollChanged(MyScrollview scrollView, intl, intt, intoldl, intoldt) {

if(t >iv.getHeight() && mTabLayout.getParent() == layout) {

layout.removeView(mTabLayout);rl_layout.addView(mTabLayout);} else if(t < iv.getHeight() && mTabLayout.getParent() == rl_layout) {

rl_layout.removeView(mTabLayout);layout.addView(mTabLayout);}

}

});}

}

就可以了

demo的github地址

Android scrollView和viewpager嵌套 指示器吸顶 根据viewpager每相关教程