Android使用Fragment来实现ViewPager的功能（解决切换Fragment状态不保存）以及各个Fragment之间的通信

 1 package com.wangjie.fragmentviewpagertest;
 2
 3 import android.app.Activity;
 4 import android.os.Bundle;
 5 import android.support.v4.app.Fragment;
 6 import android.view.LayoutInflater;
 7 import android.view.View;
 8 import android.view.ViewGroup;
 9
10 /*
11   Created with IntelliJ IDEA.
12   Author: wangjie  email:tiantian.china.2@gmail.com
13   Date: 13-6-14
14   Time: 下午2:39
15  /
16 public class TabAFm extends Fragment{
17     @Override
18     public void onAttach(Activity activity) {
19         super.onAttach(activity);
20         System.out.println(“AAAAAAAAAAonAttach”);
21     }
22
23     @Override
24     public void onCreate(Bundle savedInstanceState) {
25         super.onCreate(savedInstanceState);
26         System.out.println(“AAAAAAAAAAonCreate”);
27     }
28
29     @Override
30     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
31         System.out.println(“AAAAAAAAAAonCreateView”);
32         return inflater.inflate(R.layout.tab_a, container, false);
33     }
34
35     @Override
36     public void onActivityCreated(Bundle savedInstanceState) {
37         super.onActivityCreated(savedInstanceState);
38         System.out.println(“AAAAAAAAAAonActivityCreated”);
39     }
40
41     @Override
42     public void onStart() {
43         super.onStart();
44         System.out.println(“AAAAAAAAAAonStart”);
45     }
46
47     @Override
48     public void onResume() {
49         super.onResume();
50         System.out.println(“AAAAAAAAAAonResume”);
51     }
52
53     @Override
54     public void onPause() {
55         super.onPause();
56         System.out.println(“AAAAAAAAAAonPause”);
57     }
58
59     @Override
60     public void onStop() {
61         super.onStop();
62         System.out.println(“AAAAAAAAAAonStop”);
63     }
64
65     @Override
66     public void onDestroyView() {
67         super.onDestroyView();
68         System.out.println(“AAAAAAAAAAonDestroyView”);
69     }
70
71     @Override
72     public void onDestroy() {
73         super.onDestroy();
74         System.out.println(“AAAAAAAAAAonDestroy”);
75     }
76
77     @Override
78     public void onDetach() {
79         super.onDetach();
80         System.out.println(“AAAAAAAAAA____onDetach”);
81     }
82 }

 1 package com.wangjie.fragmentviewpagertest;
 2
 3 import android.os.Bundle;
 4 import android.support.v4.app.Fragment;
 5 import android.support.v4.app.FragmentActivity;
 6 import android.support.v4.view.ViewPager;
 7
 8 import java.util.ArrayList;
 9 import java.util.List;
10
11 public class MainActivity extends FragmentActivity {
12     private ViewPager viewPager;
13     public List<Fragment> fragments = new ArrayList<Fragment>();
14     public String hello = “hello “;
15
16     @Override
17     public void onCreate(Bundle savedInstanceState) {
18         super.onCreate(savedInstanceState);
19         setContentView(R.layout.main);
20
21         fragments.add(new TabAFm());
22         fragments.add(new TabBFm());
23         fragments.add(new TabCFm());
24         fragments.add(new TabDFm());
25         fragments.add(new TabEFm());
26
27         viewPager = (ViewPager) findViewById(R.id.viewPager);
28         FragmentViewPagerAdapter adapter = new FragmentViewPagerAdapter(this.getSupportFragmentManager(), viewPager,fragments);
29         adapter.setOnExtraPageChangeListener(new FragmentViewPagerAdapter.OnExtraPageChangeListener(){
30             @Override
31             public void onExtraPageSelected(int i) {
32                 System.out.println(“Extra…i: “ + i);
33             }
34         });
35
36     }
37
38 }

 1 <?xml version=”1.0” encoding=”utf-8”?>
 2 <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android“
 3               android:orientation=”vertical”
 4               android:layout_width=”fill_parent”
 5               android:layout_height=”fill_parent”
 6         >
 7     <android.support.v4.view.ViewPager
 8         android:id=”@+id/viewPager”
 9         android:layout_width=”match_parent”
10         android:layout_height=”match_parent”
11         />
12
13 </LinearLayout>

  1 package com.wangjie.fragmentviewpagertest;
  2
  3 import android.support.v4.app.Fragment;
  4 import android.support.v4.app.FragmentManager;
  5 import android.support.v4.app.FragmentTransaction;
  6 import android.support.v4.view.PagerAdapter;
  7 import android.support.v4.view.ViewPager;
  8 import android.view.View;
  9 import android.view.ViewGroup;
 10
 11 import java.util.List;
 12
 13 /
 14   为ViewPager添加布局（Fragment），绑定和处理fragments和viewpager之间的逻辑关系
 15  
 16   Created with IntelliJ IDEA.
 17   Author: wangjie  email:tiantian.china.2@gmail.com
 18   Date: 13-10-11
 19   Time: 下午3:03
 20  */
 21 public class FragmentViewPagerAdapter extends PagerAdapter implements ViewPager.OnPageChangeListener{
 22     private List<Fragment> fragments; // 每个Fragment对应一个Page
 23     private FragmentManager fragmentManager;
 24     private ViewPager viewPager; // viewPager对象
 25     private int currentPageIndex = 0; // 当前page索引（切换之前）
 26
 27     private OnExtraPageChangeListener onExtraPageChangeListener; // ViewPager切换页面时的额外功能添加接口
 28
 29     public FragmentViewPagerAdapter(FragmentManager fragmentManager, ViewPager viewPager , List<Fragment> fragments) {
 30         this.fragments = fragments;
 31         this.fragmentManager = fragmentManager;
 32         this.viewPager = viewPager;
 33         this.viewPager.setAdapter(this);
 34         this.viewPager.setOnPageChangeListener(this);
 35     }
 36
 37     @Override
 38     public int getCount() {
 39         return fragments.size();
 40     }
 41
 42     @Override
 43     public boolean isViewFromObject(View view, Object o) {
 44         return view == o;
 45     }
 46
 47     @Override
 48     public void destroyItem(ViewGroup container, int position, Object object) {
 49         container.removeView(fragments.get(position).getView()); // 移出viewpager两边之外的page布局
 50     }
 51
 52     @Override
 53     public Object instantiateItem(ViewGroup container, int position) {
 54         Fragment fragment = fragments.get(position);
 55         if(!fragment.isAdded()){ // 如果fragment还没有added
 56             FragmentTransaction ft = fragmentManager.beginTransaction();
 57             ft.add(fragment, fragment.getClass().getSimpleName());
 58             ft.commit();
 59             /
 60               在用FragmentTransaction.commit()方法提交FragmentTransaction对象后
 61               会在进程的主线程中，用异步的方式来执行。
 62               如果想要立即执行这个等待中的操作，就要调用这个方法（只能在主线程中调用）。
 63               要注意的是，所有的回调和相关的行为都会在这个调用中被执行完成，因此要仔细确认这个方法的调用位置。
 64              /
 65             fragmentManager.executePendingTransactions();
 66         }
 67
 68         if(fragment.getView().getParent() == null){
 69             container.addView(fragment.getView()); // 为viewpager增加布局
 70         }
 71
 72         return fragment.getView();
 73     }
 74
 75     /**
 76       当前page索引（切换之前）
 77       @return
 78      /
 79     public int getCurrentPageIndex() {
 80         return currentPageIndex;
 81     }
 82
 83     public OnExtraPageChangeListener getOnExtraPageChangeListener() {
 84         return onExtraPageChangeListener;
 85     }
 86
 87     /
 88       设置页面切换额外功能监听器
 89       @param onExtraPageChangeListener
 90      */
 91     public void setOnExtraPageChangeListener(OnExtraPageChangeListener onExtraPageChangeListener) {
 92         this.onExtraPageChangeListener = onExtraPageChangeListener;
 93     }
 94
 95     @Override
 96     public void onPageScrolled(int i, float v, int i2) {
 97         if(null != onExtraPageChangeListener){ // 如果设置了额外功能接口
 98             onExtraPageChangeListener.onExtraPageScrolled(i, v, i2);
 99         }
100     }
101
102     @Override
103     public void onPageSelected(int i) {
104         fragments.get(currentPageIndex).onPause(); // 调用切换前Fargment的onPause()
105 //        fragments.get(currentPageIndex).onStop(); // 调用切换前Fargment的onStop()
106         if(fragments.get(i).isAdded()){
107 //            fragments.get(i).onStart(); // 调用切换后Fargment的onStart()
108             fragments.get(i).onResume(); // 调用切换后Fargment的onResume()
109         }
110         currentPageIndex = i;
111
112         if(null != onExtraPageChangeListener){ // 如果设置了额外功能接口
113             onExtraPageChangeListener.onExtraPageSelected(i);
114         }
115
116     }
117
118     @Override
119     public void onPageScrollStateChanged(int i) {
120         if(null != onExtraPageChangeListener){ // 如果设置了额外功能接口
121             onExtraPageChangeListener.onExtraPageScrollStateChanged(i);
122         }
123     }
124
125
126     /
127       page切换额外功能接口
128      /
129     static class OnExtraPageChangeListener{
130         public void onExtraPageScrolled(int i, float v, int i2){}
131         public void onExtraPageSelected(int i){}
132         public void onExtraPageScrollStateChanged(int i){}
133     }
134
135
136 }

 1 @Override
 2     public void onActivityCreated(Bundle savedInstanceState) {
 3         super.onActivityCreated(savedInstanceState);
 4         System.out.println(“BBBBBBBBBBB____onActivityCreated”);
 5         this.getView().findViewById(R.id.clickme).setOnClickListener(new View.OnClickListener() {
 6             @Override
 7             public void onClick(View view) {
 8                 // 获得绑定的FragmentActivity
 9                 MainActivity activity = ((MainActivity)getActivity());
10                 // 获得TabAFm的控件
11                 EditText editText = (EditText) activity.fragments.get(0).getView().findViewById(R.id.edit);
12
13                 Toast.makeText(activity, activity.hello + editText.getText(), Toast.LENGTH_SHORT).show();
14             }
15         });
16     }