ViewPager+Fragment基本使用.doc

ViewPager+Fragment可以做出多页面滑动效果,让我们的应用程序界面操作起来更加灵活对于ViewPager和Fragment组件还不熟悉的朋友,可以先看看相关的资料首先在activity_main.xml布局文件中加入ViewPager组件 既然要实现左右的页面滑动,肯定要往ViewPager中添加一些View视图或者Fragment,这里创建了3个Fragment的布局文件 这3个布局文件非常简单,跟Activity的布局用法一模一样,代码就不贴出来了,直接看Activity的java代码package huahua.viewpager;import java.util.ArrayList;import java.util.List;import android.os.Bundle;import android.app.Activity;import android.support.v4.app.Fragment;import android.support.v4.app.FragmentActivity;import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentPagerAdapter;import android.support.v4.app.FragmentStatePagerAdapter;import android.support.v4.view.PagerTabStrip;import android.support.v4.view.PagerTitleStrip;import android.support.v4.view.ViewPager;import android.util.Log;import android.view.ViewGroup;public class MainActivity extends FragmentActivity private ViewPager m_vp;private fragment1 mfragment1;private fragment2 mfragment2;private fragment3 mfragment3;/页面列表private ArrayList fragmentList;/标题列表ArrayList titleList = new ArrayList();/通过pagerTabStrip可以设置标题的属性private PagerTabStrip pagerTabStrip;private PagerTitleStrip pagerTitleStrip;Overrideprotected void onCreate(Bundle savedInstanceState) super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);m_vp = (ViewPager)findViewById(R.id.viewpager);pagerTabStrip=(PagerTabStrip) findViewById(R.id.pagertab);/设置下划线的颜色pagerTabStrip.setTabIndicatorColor(getResources().getColor(android.R.color.holo_green_dark); /设置背景的颜色pagerTabStrip.setBackgroundColor(getResources().getColor(android.R.color.holo_blue_dark);/pagerTitleStrip=(PagerTitleStrip) findViewById(R.id.pagertab);/设置背景的颜色/pagerTitleStrip.setBackgroundColor(getResources().getColor(android.R.color.holo_blue_dark);mfragment1 = new fragment1();mfragment2 = new fragment2();mfragment3 = new fragment3();fragmentList = new ArrayList();fragmentList.add(mfragment1);fragmentList.add(mfragment2);fragmentList.add(mfragment3);titleList.add(第一页 );titleList.add(第二页);titleList.add(第三页 );m_vp.setAdapter(new MyViewPagerAdapter(getSupportFragmentManager();public class MyViewPagerAdapter extends FragmentPagerAdapterpublic MyViewPagerAdapter(FragmentManager fm) super(fm);/ TODO Auto-generated constructor stubOverridepublic Fragment getItem(int arg0) return fragmentList.get(arg0);Overridepublic int getCount() return fragmentList.size();Overridepublic CharSequence getPageTitle(int position) / TODO Auto-generated method stubreturn titleList.get(position);看到Viewpager跟ListView一样,都需要设置一个Adapter,上面代码是继承了FragmentPagerAdapter,在里面重写了3个方法.往这个Viewpager中添加了要显示的3个页面fragment和对应的3个标题接着看fragment1.javapackage huahua.viewpager;import android.os.Bundle;import android.support.v4.app.Fragment;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.Button;import android.widget.TextView;public class fragment1 extends Fragmentprivate View mMainView;private TextView tv;private Button btn;Overridepublic void onCreate(Bundle savedInstanceState) / TODO Auto-generated method stubsuper.onCreate(savedInstanceState);Log.v(huahua, fragment1-onCreate();LayoutInflater inflater = getActivity().getLayoutInflater();mMainView = inflater.inflate(R.layout.fragment1, (ViewGroup)getActivity().findViewById(R.id.viewpager), false);tv = (TextView)mMainView.findViewById(R.id.tv1);btn = (Button)mMainView.findViewById(R.id.btn1);btn.setOnClickListener(new View.OnClickListener() Overridepublic void onClick(View v) tv.setText(Hello Viewpager););Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) Log.v(huahua, fragment1-onCreateView();ViewGroup p = (ViewGroup) mMainView.getParent(); if (p != null) p.removeAllViewsInLayout(); Log.v(huahua, fragment1-移除已存在的View); return mMainView;Overridepublic void onDestroy() / TODO Auto-generated method stubsuper.onDestroy();Log.v(huahua, fragment1-onDestroy();Overridepublic void onPause() / TODO Auto-generated method stubsuper.onPause();Log.v(huahua, fragment1-onPause();Overridepublic void onResume() / TODO Auto-generated method stubsuper.onResume();Log.v(huahua, fragment1-onResume();Overridepublic void onStart() / TODO Auto-generated method stubsuper.onStart();Log.v(huahua, fragment1-onStart();Overridepublic void onStop() / TODO Auto-generated method stubsuper.onStop();Log.v(huahua, fragment1-onStop();可以看到Fragment中有个onCreateView方法,返回的是这个fragment的视图View,其他的生命周期方法都跟Activity一样,还要注意的是在回复View前一定要加入代码 ViewGroup p = (ViewGroup) mMainView.getParent(); if (p != null) p.removeAllViewsInLayout(); Log.v(huahua, fragment1-移除已存在的View); 不然在第二次加载onCreateView方法时会报异常:java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the childs parent first. 其他的2个Fragment跟这个类似,代码不贴了,直接运行程序看看效果效果图第一个页面显示出来,有个标题栏和下面的Fragment页面,主要看看在Viewpager中Fragment的生命周期是怎样的上图中可以看到除了运行fragment1中的生命周期方法,fragment2的也运行了,然后我们向右滑动到fragment2界面看看可以看到fragment3页面还没显示出来,其生命周期的方法就已经跑完了,再滑到fragment3可以看到fragment3页面显示出来,这时fragment1才onPa