Creating Swipe Views with Tabs
2017-09-26 本文已影响0人
独倚栏杆
在ViewPager一篇里面有这么一句:For more information about how to use ViewPager, read Creating Swipe Views with Tabs.所以为了探索ViewPager的全貌,决定写这一篇。
- 滑动视图提供兄弟屏幕之间的横向导航,例如具有水平手指手势(有时称为水平分页)的标签的标签。本课程教你如何创建一个带有滑动视图的选项卡布局,用于在选项卡之间切换,或者如何显示标题栏而不是选项卡。
Implement Swipe Views
在XML文件中创建ViewPager
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.view.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
要插入代表每个页面的子视图,你需要将此布局挂接到PagerAdapter。你可以使用两种适配器:
FragmentPagerAdapter
在同步屏幕之间进行导航,这表示固定的,少量的页面是最好的。
FragmentStatePagerAdapter
这最适合在不确定页数的对象集合之间进行分页。 当用户导航到其他页面时,它会破坏Fragment,从而尽量减少内存使用。
例如,以下是使用FragmentStatePagerAdapter的栗子:
public class CollectionDemoActivity extends FragmentActivity {
// When requested, this adapter returns a DemoObjectFragment,
// representing an object in the collection.
DemoCollectionPagerAdapter mDemoCollectionPagerAdapter;
ViewPager mViewPager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_collection_demo);
// ViewPager and its adapters use support library
// fragments, so use getSupportFragmentManager.
mDemoCollectionPagerAdapter =
new DemoCollectionPagerAdapter(
getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mDemoCollectionPagerAdapter);
}
}
// Since this is an object collection, use a FragmentStatePagerAdapter,
// and NOT a FragmentPagerAdapter.
public class DemoCollectionPagerAdapter extends FragmentStatePagerAdapter {
public DemoCollectionPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int i) {
Fragment fragment = new DemoObjectFragment();
Bundle args = new Bundle();
// Our object is just an integer :-P
args.putInt(DemoObjectFragment.ARG_OBJECT, i + 1);
fragment.setArguments(args);
return fragment;
}
@Override
public int getCount() {
return 100;
}
@Override
public CharSequence getPageTitle(int position) {
return "OBJECT " + (position + 1);
}
}
// Instances of this class are fragments representing a single
// object in our collection.
public static class DemoObjectFragment extends Fragment {
public static final String ARG_OBJECT = "object";
@Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
// The last two arguments ensure LayoutParams are inflated
// properly.
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;
}
}
此示例仅显示创建滑动视图所需的代码。 以下部分显示如何添加选项卡,以帮助促进页面之间的导航。
Add Tabs to the Action Bar
未完待续。。。