viewpager的基本用法

2019-11-09 15:06:38

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ViewPager继承自ViewGroup，用以实现页面的左右滑动。

1）ViewPager类直接继承了ViewGroup类，所有它是一个容器类，可以在其中添加其他的view类。

2）ViewPager类需要一个PagerAdapter适配器类给它提供数据。

3）ViewPager经常和Fragment一起使用，并且提供了专门的FragmentPagerAdapter和FragmentStatePagerAdapter类供Fragment中的ViewPager使用。

在编写ViewPager的应用的使用，还需要使用两个组件类分别是PagerTitleStrip类和PagerTabStrip类，PagerTitleStrip类直接继承自ViewGroup类，而PagerTabStrip类继承PagerTitleStrip类，所以这两个类也是容器类。但是有一点需要注意，在定义xml的layout的时候，这两个类必须是ViewPager标签的子标签，不然会出错。

fragment_collection_object.xml必不可少

<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/activity_collection_demo_pager" android:layout_width="match_parent" android:layout_height="match_parent"> <android.support.v4.view.PagerTitleStrip android:id="@+id/pager_title_strip" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_gravity="top" android:background="#33b5e5" android:textColor="#fff" android:paddingTop="4dp" android:paddingBottom="4dp" /></android.support.v4.view.ViewPager>

这里写图片描述

主要类共5个： CollectionDemoActivity.java，显示控制页面 activity_collection_demo.xml，显示页面的xml DemoCollectionPagerAdapter.java，viewpager的数据填充adapter DemoObjectFragment.java，数字显示控制页面 fragment_collection_object.xml，fragment的xml布局

/** 显示数字的Fragment */

public static class DemoObjectFragment extends Fragment { public static final String ARG_OBJECT = "object"; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_collection_object, container, false); Bundle args = getArguments(); ((TextView) rootView.findViewById(android.R.id.text1)).setText( Integer.toString(args.getInt(ARG_OBJECT))); return rootView; } }

/**填充viewpager */

public static class DemoCollectionPagerAdapter extends FragmentStatePagerAdapter { public DemoCollectionPagerAdapter(FragmentManager fm) { super(fm); } @Override public Fragment getItem(int i) { Fragment fragment = new DemoObjectFragment(); Bundle args = new Bundle(); args.putInt(DemoObjectFragment.ARG_OBJECT, i + 1); // Our object is just an integer :-P fragment.setArguments(args); return fragment; } @Override public int getCount() { //有100个子项 return 100; } @Override public CharSequence getPageTitle(int position) { return "OBJECT " + (position + 1); } }

//主activity

public class CollectionDemoActivity extends FragmentActivity { DemoCollectionPagerAdapter mDemoCollectionPagerAdapter; ViewPager mViewPager; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_collection_demo); mDemoCollectionPagerAdapter = new DemoCollectionPagerAdapter(getSupportFragmentManager()); mViewPager = (ViewPager) findViewById(R.id.activity_collection_demo_pager); mViewPager.setAdapter(mDemoCollectionPagerAdapter); } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case android.R.id.home: // This is called when the Home (Up) button is PRessed in the action bar. // Create a simple intent that starts the hierarchical parent activity and // use NavUtils in the Support Package to ensure proper handling of Up. Intent upIntent = new Intent(this, MainActivity.class); if (NavUtils.shouldUpRecreateTask(this, upIntent)) { // This activity is not part of the application's task, so create a new task // with a synthesized back stack. TaskStackBuilder.from(this) // If there are ancestor activities, they should be added here. .addNextIntent(upIntent) .startActivities(); finish(); } else { // This activity is part of the application's task, so simply // navigate up to the hierarchical parent activity. NavUtils.navigateUpTo(this, upIntent); } return true; } return super.onOptionsItemSelected(item); } }

fragment_collection_object.xml

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