ViewPager+FragmentTabHost

本文主要是介绍ViewPager+FragmentTabHost，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

普通的ViewPager的使用

使用方法参考listview1.在布局中使用support.v4包下的viewpager控件<android.support.v4.view.ViewPagerandroid:id="@+id/vp"android:layout_width="match_parent"android:layout_height="0dp"android:layout_weight="1"></android.support.v4.view.ViewPager>vp = (ViewPager) findViewById(R.id.vp);     2.创建PagerAdapter的子类
必须实现如下四个方法
public class MyPagerAdapter extends PagerAdapter {List<View>datas;public MyPagerAdapter(List<View> datas) {this.datas = datas;}@Overridepublic int getCount() {return datas.size();}//通过该方法开确定要展示哪个view@Overridepublic boolean isViewFromObject(View view, Object object) {return view==object;}@Overridepublic Object instantiateItem(ViewGroup container, int position) {View view = datas.get(position);container.addView(view);//这个view就是isViewFromObject中的第二个参数return view;}@Overridepublic void destroyItem(ViewGroup container, int position, Object object) {container.removeView(datas.get(position));}
}3.展示数据
//调用vp.setadapter方法展示
vp.setadater(adapter);

FragmentViewPager的使用

需要先介绍一下
fragmentadapter有两种,分别是FragmentStatePagerAdapter和FragmentPagerAdapter;
FragmentStatePagerAdapter 和前面的 FragmentPagerAdapter 一样，是继承子 PagerAdapter。但是，和 FragmentPagerAdapter 不一样的是，正如其类名中的 'State' 所表明的含义一样，该 PagerAdapter 的实现将只保留当前页面，当页面离开视线后，就会被消除，释放其资源;
简单的说就是fragment被隐藏后FragmentStatePagerAdapter 会调用fragment的destroy方法,而FragmentPagerAdapter不会;前者适合有大量大framgent中使用;

//也可以改成继承于FragmentPagerAdapter 
public class MyFragmentPagerAdapter extends FragmentStatePagerAdapter {List<Fragment> mDatas;//相比于pageradapter,不需要实现instantiateItem()destroyItem()public MyFragmentPagerAdapter(FragmentManager fm,List<Fragment> datas) {super(fm);mDatas=datas;}@Overridepublic int getCount() {return mDatas.size();}@Overridepublic Fragment getItem(int position) {return mDatas.get(position);}
}

设置监听器

viewPager.setAdapter(new MyViewPagerAdapter(views));
//设置当前打开的页面是第几个
viewPager.setCurrentItem(0);
viewPager.setOnPageChangeListener(new MyOnPageChangeListener());//设置页面切换的监听

设置viewpager的切换动画效果

1.谷歌的demo
public class DepthPageTransformer implements ViewPager.PageTransformer {private static final float MIN_SCALE = 0.75f;public void transformPage(View view, float position) {int pageWidth = view.getWidth();if (position < -1) { // [-Infinity,-1)// This page is way off-screen to the left.view.setAlpha(0);} else if (position <= 0) { // [-1,0]// Use the default slide transition when moving to the left pageview.setAlpha(1);view.setTranslationX(0);view.setScaleX(1);view.setScaleY(1);} else if (position <= 1) { // (0,1]// Fade the page out.view.setAlpha(1 - position);// Counteract the default slide transitionview.setTranslationX(pageWidth * -position);// Scale the page down (between MIN_SCALE and 1)float scaleFactor = MIN_SCALE+ (1 - MIN_SCALE) * (1 - Math.abs(position));view.setScaleX(scaleFactor);view.setScaleY(scaleFactor);} else { // (1,+Infinity]// This page is way off-screen to the right.view.setAlpha(0);}}
}2.
//第一个参数为false表示当进入和退出动画重叠时,能同时显示,不会被遮盖
vp.setPageTransformer(true,new Translate());

FragmentTabHost的使用

布局
<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"tools:context="com.junx.tabhost.MainActivity"><FrameLayout//用于显示fragmentandroid:id="@+id/fl"android:layout_width="match_parent"android:layout_height="0dp"android:layout_weight="1"android:background="#F00"></FrameLayout>//底部导航栏<android.support.v4.app.FragmentTabHostandroid:id="@+id/tab_frag"android:layout_width="match_parent"android:layout_height="100dp"></android.support.v4.app.FragmentTabHost>
</LinearLayout>

代码:String tabs[] = new String[]{"哈哈1", "哈哈2", "哈哈3"};Class classes[]={ItemFragment1.class,ItemFragment2.class,ItemFragment3.class};private void show() {//将tab和展示不同fragment的fl绑定tab_frag.setup(this,getSupportFragmentManager(),R.id.fl);//去掉导航栏间的分割线tab_frag.getTabWidget().setDividerDrawable(null);for (int i = 0; i < tabs.length; i++) {TabHost.TabSpec tabSpec = tab_frag.newTabSpec(tabs[i]);tabSpec.setIndicator(getView(i));tab_frag.addTab(tabSpec,classes[i],null);}}//返回tab中item的布局的inflatedpublic View getView(int i) {View inflate = View.inflate(this,R.layout.tab_item, null);ImageView view = inflate.findViewById(R.id.tab_imageview);view.setBackgroundResource(R.drawable.timg);TextView tv = inflate.findViewById(R.id.tab_textview);tv.setText(tabs[i]);return inflate;}

ViewPager+FragmentTabHost

1.布局,在页面的下方放置tab<android.support.v4.app.FragmentTabHostandroid:id="@+id/tab_host"android:layout_width="match_parent" android:layout_height="100dp"></android.support.v4.app.FragmentTabHost>
代码中:
tab_host = (FragmentTabHost) findViewById(R.id.tab_host);2.将tab和viewpager绑定
tab_host.setup(this,getSupportFragmentManager(),R.id.vp);//vp的监听实现tab_host.setOnTabChangedListener(this);@Overridepublic void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}@Overridepublic void onPageSelected(int position) {tab_host.setCurrentTab(position);}@Overridepublic void onPageScrollStateChanged(int state) {}//tab的变化监听@Overridepublic void onTabChanged(String tabId) {//修改选中的tab的positionint position = tab_host.getCurrentTab();vp.setCurrentItem(position);}3.为tab填充内容for (int i = 0; i < mFragments.size(); i++) {//设置文字提示TabHost.TabSpec tabSpec = tab_host.newTabSpec("??");//设置图片view,该view中的imageview的src不能为selector,否则报错原因名不明    tabSpec.setIndicator(getTab(i));//绑定fragment,记得要调用三个参数的addTab()tab_host.addTab(tabSpec,mFragments.get(i).getClass(),null);}
//
tab_host.setOnTabChangedListener(this);@Overridepublic void onTabChanged(String tabId) {//获取当前点击的tab的idint position = tab_host.getCurrentTab();vp.setCurrentItem(position);}

FragmentTabHost自定义导航栏布局

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