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(); } }