1.FragmentStatePageAdapter
适用与list之类的集合,不会大量保存在内存中,只是缓存了部分
/**
* Implementation of {@link android.support.v4.view.PagerAdapter} that
* uses a {@link Fragment} to manage each page. This class also handles
* saving and restoring of fragment's state.
*
* <p>This version of the pager is more useful when there are a large number
* of pages, working more like a list view. When pages are not visible to
* the user, their entire fragment may be destroyed, only keeping the saved
* state of that fragment. This allows the pager to hold on to much less
* memory associated with each visited page as compared to
* {@link FragmentPagerAdapter} at the cost of potentially more overhead when
* switching between pages.
*
* <p>When using FragmentPagerAdapter the host ViewPager must have a
* valid ID set.</p>
*
* <p>Subclasses only need to implement {@link #getItem(int)}
* and {@link #getCount()} to have a working adapter.
*
* <p>Here is an example implementation of a pager containing fragments of
* lists:
*
* {@sample development/samples/Support13Demos/src/com/example/android/supportv13/app/FragmentStatePagerSupport.java
* complete}
*
* <p>The <code>R.layout.fragment_pager</code> resource of the top-level fragment is:
*
* {@sample development/samples/Support13Demos/res/layout/fragment_pager.xml
* complete}
*
* <p>The <code>R.layout.fragment_pager_list</code> resource containing each
* individual fragment's layout is:
*
* {@sample development/samples/Support13Demos/res/layout/fragment_pager_list.xml
* complete}
*/
2.FragmentPageAdapter
适用于开始页面的几个Fragment,少量的页面会缓存
/**
* Implementation of {@link android.support.v4.view.PagerAdapter} that
* represents each page as a {@link Fragment} that is persistently
* kept in the fragment manager as long as the user can return to the page.
*
* <p>This version of the pager is best for use when there are a handful of
* typically more static fragments to be paged through, such as a set of tabs.
* The fragment of each page the user visits will be kept in memory, though its
* view hierarchy may be destroyed when not visible. This can result in using
* a significant amount of memory since fragment instances can hold on to an
* arbitrary amount of state. For larger sets of pages, consider
* {@link FragmentStatePagerAdapter}.
*
* <p>When using FragmentPagerAdapter the host ViewPager must have a
* valid ID set.</p>
*
* <p>Subclasses only need to implement {@link #getItem(int)}
* and {@link #getCount()} to have a working adapter.
*
* <p>Here is an example implementation of a pager containing fragments of
* lists:
*
* {@sample development/samples/Support4Demos/src/com/example/android/supportv4/app/FragmentPagerSupport.java
* complete}
*
* <p>The <code>R.layout.fragment_pager</code> resource of the top-level fragment is:
*
* {@sample development/samples/Support4Demos/res/layout/fragment_pager.xml
* complete}
*
* <p>The <code>R.layout.fragment_pager_list</code> resource containing each
* individual fragment's layout is:
*
* {@sample development/samples/Support4Demos/res/layout/fragment_pager_list.xml
* complete}
*/