标签:android style blog http os io 使用 java ar
上一篇写过FragmentPagerAdapter,这篇来介绍FragmentStatePagerAdapter,那么两者之间有何差别呢:
FragmentPagerAdapter很多其它的用于少量界面的ViewPager,比方Tab。划过的fragment会保存在内存中,虽然已经划过。而FragmentStatePagerAdapter和ListView有点类似,会保存当前界面,以及下一个界面和上一个界面(假设有),最多保存3个,其它会被销毁掉。
假设想要更具体的了解,能够查看官网API,以下给出依照官网上写出的Demo:
实现效果图:
源码:
布局文件:
fragment_pager.xml(布局了ViewPager和两个button):
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center_horizontal" android:orientation="vertical" android:padding="4dip" > <android.support.v4.view.ViewPager android:id="@+id/pager" android:layout_width="match_parent" android:layout_height="0px" android:layout_weight="1" > </android.support.v4.view.ViewPager> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_weight="0" android:gravity="center" android:measureWithLargestChild="true" android:orientation="horizontal" > <Button android:id="@+id/goto_first" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="调到首页" > </Button> <Button android:id="@+id/goto_last" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="调到尾页" > </Button> </LinearLayout> </LinearLayout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@android:drawable/gallery_thumb" android:orientation="vertical" > <!-- 该Textview用来显示Fragment的页数 --> <TextView android:id="@+id/text" android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="center_vertical|center_horizontal" android:text="@string/hello_world" android:textAppearance="?android:attr/textAppearanceMedium" /> <!-- 不为空用来显示ListView,假设为空,则显示TextView(数据为空) --> <FrameLayout android:layout_width="match_parent" android:layout_height="0dip" android:layout_weight="1" > <ListView android:id="@android:id/list" android:layout_width="match_parent" android:layout_height="match_parent" android:drawSelectorOnTop="false" /> <TextView android:id="@android:id/empty" android:layout_width="match_parent" android:layout_height="match_parent" android:text="数据为空" android:textAppearance="?android:attr/textAppearanceMedium" /> </FrameLayout> </LinearLayout>
MainActivity:
package com.fragmentdemo13_fragmentstatepageradapter; import android.os.Bundle; import android.support.v4.app.FragmentActivity; import android.support.v4.view.ViewPager; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; /** * 这里我们调用的是support.v4的包,所以MainActivity继承的是FragmentActivity,而不是Activity。 */ public class MainActivity extends FragmentActivity { public static final int NUM_ITEMS = 10; private MyAdapter mAdapter; private ViewPager mPager; private Button button_first, button_last; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fragment_pager); /** * 相同,因为调用的是support.v4的包,这里是getSupportFragmentManager(),而不是getFragmentManager(); */ mAdapter = new MyAdapter(getSupportFragmentManager()); mPager = (ViewPager) findViewById(R.id.pager); mPager.setAdapter(mAdapter); /** * 点击返回首页 */ button_first = (Button) findViewById(R.id.goto_first); button_first.setOnClickListener(new OnClickListener() { public void onClick(View v) { mPager.setCurrentItem(0); } }); /** * 点击返回尾页 */ button_last = (Button) findViewById(R.id.goto_last); button_last.setOnClickListener(new OnClickListener() { public void onClick(View v) { mPager.setCurrentItem(NUM_ITEMS - 1); } }); } }
package com.fragmentdemo13_fragmentstatepageradapter; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentStatePagerAdapter; /** * 这里继承的是FragmentStatePagerAdapter, 依据官方API的介绍,当项目中遇到使用大量的列表页面时,使用该适配器是个更好的选择。 * (This version of the pager is more useful when there are a large number of * pages, working more like a list view.) */ public class MyAdapter extends FragmentStatePagerAdapter { public MyAdapter(FragmentManager fm) { super(fm); } /** * 仅仅须要实现以下两个方法就可以。 */ @Override public Fragment getItem(int position) { return ArrayListFragment.newInstance(position); } @Override public int getCount() { return MainActivity.NUM_ITEMS; } }
package com.fragmentdemo13_fragmentstatepageradapter; import java.util.ArrayList; import android.os.Bundle; import android.support.v4.app.ListFragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ArrayAdapter; import android.widget.ListView; import android.widget.TextView; import android.widget.Toast; public class ArrayListFragment extends ListFragment { private int mNum; public ArrayList<String> list = new ArrayList<String>(); /** * 创建一个计算Fragment页面的实例,将怒num作为一个參数。 * (Create a new instance of * CountingFragment, providing "num" as an argument.) */ public static ArrayListFragment newInstance(int num) { ArrayListFragment f = new ArrayListFragment(); Bundle args = new Bundle(); args.putInt("num", num); f.setArguments(args); return f; } /** * 当调用该方法时,检索此实例的数量的參数。 * (When creating, retrieve this instance's number from * its arguments.) */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mNum = getArguments() != null ? getArguments().getInt("num") : 1; } /** * Fragment的UI仅仅显示它所在的页码。 * (The Fragment's UI is just a simple text view * showing its instance number.) */ @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate(R.layout.fragment_pager_list, container, false); TextView tv = (TextView) view.findViewById(R.id.text); tv.setText("Fragment #" + mNum); return view; } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); setListAdapter(new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, getData())); } /** * 在每个Fragment列表中展示的数据。 */ private ArrayList<String> getData() { for (int i = 0; i < 20; i++) { list.add("nihao" + i); } return list; } @Override public void onListItemClick(ListView l, View v, int position, long id) { Toast.makeText(getActivity(), "您点击了"+position, 0).show(); } }
Android FragmentStatePageAdapter的使用Demo
标签:android style blog http os io 使用 java ar
原文地址:http://www.cnblogs.com/mfrbuaa/p/3957802.html