详解Android App中创建ViewPager组件的方法

现在很多app一打开就是一个ViewPager，然后可以用手指滑，每滑一次就换一张图，底下还会有圈圈表示说现在滑到第几章~
通常这些图片都是放功能简介或是使用教学之类的，我的需求很简单，就是上面提到的那样而已。
有两种做法，一种是找现有套件，查了一堆资料每个都跟我推荐ViewPagerIndicator这套，我之前也看过这套，只是看起来需要有fragment再加上google play范例好像载不到了，所以只好自己实做一个。
Viewpager的实作可参考Android ViewPager使用详解里面的程序码:

@Overrideprotected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_intro);

mViewPager = (ViewPager) findViewById(R.id.viewpager);

final LayoutInflater mInflater = getLayoutInflater().from(this);

View v1 = mInflater.inflate(R.layout.intro_layout_1, null);
 View v2 = mInflater.inflate(R.layout.intro_layout_2, null);
 View v3 = mInflater.inflate(R.layout.intro_layout_3, null);
 View v4 = mInflater.inflate(R.layout.intro_layout_4, null);

viewList = new ArrayList<View>();
 viewList.add(v1);
 viewList.add(v2);
 viewList.add(v3);
 viewList.add(v4);

mViewPager.setAdapter(new MyViewPagerAdapter(viewList));
 mViewPager.setCurrentItem(0);}
MyViewPagerAdapter
public class MyViewPagerAdapter extends PagerAdapter {
 private List<View> mListViews;

public MyViewPagerAdapter(List<View> mListViews) {
   this.mListViews = mListViews;
 }

@Override
 public void destroyItem(ViewGroup container, int position, Object object)  {
   container.removeView((View) object);
 }

@Override
 public Object instantiateItem(ViewGroup container, int position) {
   View view = mListViews.get(position);
   container.addView(view);
   return view;
 }

@Override
 public int getCount() {
   return mListViews.size();
 }

@Override
 public boolean isViewFromObject(View arg0, Object arg1) {
   return arg0==arg1;
 }}

这样子你就有一个ViewPager了

下面我们来具体看一下ViewPager的用法：
一、ViewPager创建步骤
① 在XML布局中加入android.support.v4.view.ViewPager

② 加载显示的页卡将Layout布局转换为View对象

  (1) 

LayoutInflater lf getLayoutInflater().from(this);
 lf.inflate(resource,root);

  (2)

View.inflate(context,resource,root);

③ 配置Adapter（三种Adapter）

 (1)PagerAdapter 数据源：List<View>
 (2)FragmentPagerAdapter 数据源：List<Fragment>
 (3)FragmentStatePagerAdapter 数据源：List<Fragment>
二、代码示例
新建四个Fragment和他们的布局下面是MainActivity的xml布局：

<android.support.v4.view.ViewPager
   android:id="@+id/pager"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:layout_gravity="center" >

<android.support.v4.view.PagerTabStrip
     android:id="@+id/tab"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:layout_gravity="top" >
   </android.support.v4.view.PagerTabStrip>
   <!-- 底部显示标题与上面的顶部显示不能同时出现
   <android.support.v4.view.PagerTitleStrip
     android:id="@+id/title"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:layout_gravity="bottom" >
   </android.support.v4.view.PagerTitleStrip>
   -->
 </android.support.v4.view.ViewPager>

第一种PagerAdapter

public class MyPagerAdapter extends PagerAdapter {

private List<View> viewList;
 private List<String> titleList;

public MyPagerAdapter(List<View> viewList,List<String> titleList){
   this.viewList = viewList;
   this.titleList = titleList;
 }

/**
  * 返回页卡的数量
  */
 @Override
 public int getCount() {

return viewList.size();
 }

/**
  * view是否来自对象
  */
 @Override
 public boolean isViewFromObject(View arg0, Object arg1) {

return arg0==arg1;
 }
  /**
  * 实例化一个页卡
  */
 @Override
 public Object instantiateItem(ViewGroup container, int position) {
   container.addView(viewList.get(position));
   return viewList.get(position);
 }
  /**
  * 销毁一个页卡
  */
 @Override
 public void destroyItem(ViewGroup container, int position, Object object) {

container.removeView(viewList.get(position));

}

/**
  * 设置ViewPager的标题
  */
 @Override
 public CharSequence getPageTitle(int position) {

return titleList.get(position);
 }

}

第二种FragmentPagerAdapter

public class MyFragmentPagerAdapter extends FragmentPagerAdapter {
 private List<Fragment> fragList;
 private List<String> titleList;
 public MyFragmentPagerAdapter(FragmentManager fm,List<Fragment> fragList,List<String> titleList) {
   super(fm);
   this.fragList = fragList;
   this.titleList = titleList;
 }

@Override
 public Fragment getItem(int arg0) {

return fragList.get(arg0);
 }

@Override
 public CharSequence getPageTitle(int position) {

return titleList.get(position);
 }

@Override
 public int getCount() {

return fragList.size();
 }

}

第三种FragmentStatePagerAdapter（该适配器可以动态销毁Fragment）

public class MyFragmentPagerAdapter2 extends FragmentStatePagerAdapter {//该适配器可以动态销毁
 private List<Fragment> fragList;
 private List<String> titleList;
 public MyFragmentPagerAdapter2(FragmentManager fm,List<Fragment> fragList,List<String> titleList) {
   super(fm);
   this.fragList = fragList;
   this.titleList = titleList;
 }

@Override
 public Fragment getItem(int arg0) {

return fragList.get(arg0);
 }

@Override
 public CharSequence getPageTitle(int position) {

return titleList.get(position);
 }

@Override
 public int getCount() {

return fragList.size();
 }

@Override
 public Object instantiateItem(ViewGroup arg0, int arg1) {

return super.instantiateItem(arg0, arg1);
 }
 @Override
 public void destroyItem(ViewGroup container, int position, Object object) {

super.destroyItem(container, position, object);
 }

}

MainActivity里使用getSupportFragmentManager()该Activity必须继承FragmentActivity：

public class MainActivity extends FragmentActivity implements OnPageChangeListener{
 private List<View> viewList;
 private List<String> titleList;
 private ViewPager pager;
 private PagerTabStrip tab;//顶部标题

private List<Fragment> fragList;

@Override
 protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_main);
   viewList = new ArrayList<View>();
   titleList = new ArrayList<String>();
   tab = (PagerTabStrip) findViewById(R.id.tab);

View view1 = View.inflate(this,R.layout.view1,null);
   View view2 = View.inflate(this,R.layout.view2,null);
   View view3 = View.inflate(this,R.layout.view3,null);
   View view4 = View.inflate(this,R.layout.view4,null);

viewList.add(view1);
   viewList.add(view2);
   viewList.add(view3);
   viewList.add(view4);

fragList = new ArrayList<Fragment>();
   fragList.add(new Fragment1());
   fragList.add(new Fragment2());
   fragList.add(new Fragment3());
   fragList.add(new Fragment4());

//为ViewPager页卡设置标题
   titleList.add("第一页");
   titleList.add("第二页");
   titleList.add("第三页");
   titleList.add("第四页");
   //为PagerTabStrip设置一些属性
   tab.setBackgroundColor(Color.WHITE);
   tab.setDrawFullUnderline(false);
   tab.setTabIndicatorColor(Color.BLUE);

pager = (ViewPager) findViewById(R.id.pager);
   //MyPagerAdapter adapter = new MyPagerAdapter(viewList,titleList);
   //MyFragmentPagerAdapter adapter = new MyFragmentPagerAdapter(getSupportFragmentManager(), fragList, titleList);
   /**
    * 使用getSupportFragmentManager()该Activity必须继承FragmentActivity
    */
   MyFragmentPagerAdapter2 adapter = new MyFragmentPagerAdapter2(getSupportFragmentManager(), fragList, titleList);
   pager.setAdapter(adapter);
   pager.setOnPageChangeListener(this);
 }

@Override
 public void onPageScrollStateChanged(int arg0) {

}

@Override
 public void onPageScrolled(int arg0, float arg1, int arg2) {

}

@Override
 public void onPageSelected(int arg0) {
   Toast.makeText(this,"当前是第"+(arg0+1)+"个界面", 0).show();

}

}