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

以下内容为原创,转载请注明:http://www.cnblogs.com/tiantianbyconan/p/3360938.html

如新浪微博下面的标签切换功能,我以前也写过一篇博文(http://www.cnblogs.com/tiantianbyconan/archive/2012/02/24/2366237.html),可以实现,用的是TabHost。但是android发展比较迅速,TabHost这玩意现在已经被弃用了,虽说用现在也能用,但是被弃用的东西还是少用为妙。

官方有个FragmentTabHost这么一个替代品,于是试了一下,发现每次切换tab,都会调用onCreateView()方法,控件被重新加载,也就是说你从tab1切换到别的tab后,再切换回来,tab1的状态并没有保存,重新加载了控件。

搞了半天,暂时没有好的解决办法(有朋友知道解决办法的话,希望联系我,赐教下哈)

于是,怒了,自己实现一个吧- -

 

先来看看整个demo的结构:

TabAFm到TabEFm都是Fragment,并且每个Fragment对应一个布局文件。

TabAFm.java:

 1 package com.wangjie.fragmenttabhost;
 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("AAAAAAAAAA____onAttach");
21     }
22 
23     @Override
24     public void onCreate(Bundle savedInstanceState) {
25         super.onCreate(savedInstanceState);
26         System.out.println("AAAAAAAAAA____onCreate");
27     }
28 
29     @Override
30     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
31         System.out.println("AAAAAAAAAA____onCreateView");
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("AAAAAAAAAA____onActivityCreated");
39     }
40 
41     @Override
42     public void onStart() {
43         super.onStart();
44         System.out.println("AAAAAAAAAA____onStart");
45     }
46 
47     @Override
48     public void onResume() {
49         super.onResume();
50         System.out.println("AAAAAAAAAA____onResume");
51     }
52 
53     @Override
54     public void onPause() {
55         super.onPause();
56         System.out.println("AAAAAAAAAA____onPause");
57     }
58 
59     @Override
60     public void onStop() {
61         super.onStop();
62         System.out.println("AAAAAAAAAA____onStop");
63     }
64 
65     @Override
66     public void onDestroyView() {
67         super.onDestroyView();
68         System.out.println("AAAAAAAAAA____onDestroyView");
69     }
70 
71     @Override
72     public void onDestroy() {
73         super.onDestroy();
74         System.out.println("AAAAAAAAAA____onDestroy");
75     }
76 
77     @Override
78     public void onDetach() {
79         super.onDetach();
80         System.out.println("AAAAAAAAAA____onDetach");
81     }
82 }
View Code

如上述代码所示,TabAFm是一个Fragment,对应的布局文件是tab_a.xml,并实现了他的所有的生命周期回调函数并打印,便于调试

tab_a.xml布局中有个EditText

其他的Fragment大同小异,这里就不贴出代码了

 

现在来看MainActivity:

 1 package com.wangjie.fragmenttabhost;
 2 
 3 import android.os.Bundle;
 4 import android.support.v4.app.Fragment;
 5 import android.support.v4.app.FragmentActivity;
 6 import android.widget.RadioGroup;
 7 
 8 import java.util.ArrayList;
 9 import java.util.List;
10 
11 public class MainActivity extends FragmentActivity {
12     /**
13      * Called when the activity is first created.
14      */
15     private RadioGroup rgs;
16     public List<Fragment> fragments = new ArrayList<Fragment>();
17 
18     public String hello = "hello ";
19 
20     @Override
21     public void onCreate(Bundle savedInstanceState) {
22         super.onCreate(savedInstanceState);
23         setContentView(R.layout.main);
24 
25         fragments.add(new TabAFm());
26         fragments.add(new TabBFm());
27         fragments.add(new TabCFm());
28         fragments.add(new TabDFm());
29         fragments.add(new TabEFm());
30 
31 
32         rgs = (RadioGroup) findViewById(R.id.tabs_rg);
33 
34         FragmentTabAdapter tabAdapter = new FragmentTabAdapter(this, fragments, R.id.tab_content, rgs);
35         tabAdapter.setOnRgsExtraCheckedChangedListener(new FragmentTabAdapter.OnRgsExtraCheckedChangedListener(){
36             @Override
37             public void OnRgsExtraCheckedChanged(RadioGroup radioGroup, int checkedId, int index) {
38                 System.out.println("Extra---- " + index + " checked!!! ");
39             }
40         });
41 
42     }
43 
44 }
View Code

MainActivity上述代码所示

MainActivity是包含Fragment的Activity(也就是这里的5个Fragment)

他继承了FragmentActivity(因为我这里用的是android-support-v4.jar)

用一个List<Fragment>去维护5个Fragment,也就是5个tab

main布局中有一个id为tab_content的FrameLayout,用来存放要显示的Fragment。底部有一个RadioGroup,用于tab的切换,如下:

  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               android:background="@android:color/white"
  7         >
  8     <LinearLayout
  9             android:layout_width="fill_parent"
 10             android:layout_height="fill_parent"
 11             android:orientation="vertical"
 12         >
 13 
 14     <FrameLayout
 15             android:id="@+id/tab_content"
 16             android:layout_width="fill_parent"
 17             android:layout_height="0dp"
 18             android:layout_weight="1.0"
 19             android:background="#77557799"
 20             />
 21 
 22     <RadioGroup
 23             android:id="@+id/tabs_rg"
 24             android:layout_width="fill_parent"
 25             android:layout_height="wrap_content"
 26             android:orientation="horizontal"
 27             android:gravity="center"
 28             android:paddingTop="7dp"
 29             android:paddingBottom="7dp"
 30             >
 31         <RadioButton
 32                 android:id="@+id/tab_rb_a"
 33                 android:layout_width="0dp"
 34                 android:layout_height="wrap_content"
 35                 android:drawableTop="@drawable/tablatestalert"
 36                 android:button="@null"
 37                 android:text="Tab1"
 38                 android:textColor="#000000"
 39                 android:textSize="13sp"
 40                 android:layout_weight="1.0"
 41                 android:gravity="center"
 42                 android:singleLine="true"
 43                 android:checked="true"
 44                 android:background="@drawable/selector_tab"
 45                 />
 46         <RadioButton
 47                 android:id="@+id/tab_rb_b"
 48                 android:layout_width="0dp"
 49                 android:layout_height="wrap_content"
 50                 android:drawableTop="@drawable/tabsearch"
 51                 android:button="@null"
 52                 android:text="Tab2"
 53                 android:textColor="#000000"
 54                 android:textSize="13sp"
 55                 android:layout_weight="1.0"
 56                 android:gravity="center"
 57                 android:singleLine="true"
 58                 android:background="@drawable/selector_tab"
 59                 />
 60         <RadioButton
 61                 android:id="@+id/tab_rb_c"
 62                 android:layout_width="0dp"
 63                 android:layout_height="wrap_content"
 64                 android:drawableTop="@drawable/tabrecommd"
 65                 android:button="@null"
 66                 android:text="Tab3"
 67                 android:textColor="#000000"
 68                 android:textSize="13sp"
 69                 android:layout_weight="1.0"
 70                 android:gravity="center"
 71                 android:singleLine="true"
 72                 android:background="@drawable/selector_tab"
 73                 />
 74         <RadioButton
 75                 android:id="@+id/tab_rb_d"
 76                 android:layout_width="0dp"
 77                 android:layout_height="wrap_content"
 78                 android:drawableTop="@drawable/tabconfigicon"
 79                 android:button="@null"
 80                 android:text="Tab4"
 81                 android:textColor="#000000"
 82                 android:textSize="13sp"
 83                 android:layout_weight="1.0"
 84                 android:gravity="center"
 85                 android:singleLine="true"
 86                 android:background="@drawable/selector_tab"
 87                 />
 88         <RadioButton
 89                 android:id="@+id/tab_rb_e"
 90                 android:layout_width="0dp"
 91                 android:layout_height="wrap_content"
 92                 android:drawableTop="@drawable/tababoutus"
 93                 android:button="@null"
 94                 android:text="Tab5"
 95                 android:textColor="#000000"
 96                 android:textSize="13sp"
 97                 android:layout_weight="1.0"
 98                 android:gravity="center"
 99                 android:singleLine="true"
100                 android:background="@drawable/selector_tab"
101                 />
102 
103     </RadioGroup>
104     </LinearLayout>
105 </LinearLayout>
View Code

现在回到MainActivity中,下面这个FragmentTabAdapter类是关键,是我自己编写的用于绑定和处理fragments和RadioGroup之间的逻辑关系

FragmentTabAdapter tabAdapter = new FragmentTabAdapter(this, fragments, R.id.tab_content, rgs);

 

现在看下FragmentTabAdapter:

  1 package com.wangjie.fragmenttabhost;
  2 
  3 import android.support.v4.app.Fragment;
  4 import android.support.v4.app.FragmentActivity;
  5 import android.support.v4.app.FragmentTransaction;
  6 import android.widget.RadioGroup;
  7 
  8 import java.util.List;
  9 
 10 /**
 11  * Created with IntelliJ IDEA.
 12  * Author: wangjie  email:tiantian.china.2@gmail.com
 13  * Date: 13-10-10
 14  * Time: 上午9:25
 15  */
 16 public class FragmentTabAdapter implements RadioGroup.OnCheckedChangeListener{
 17     private List<Fragment> fragments; // 一个tab页面对应一个Fragment
 18     private RadioGroup rgs; // 用于切换tab
 19     private FragmentActivity fragmentActivity; // Fragment所属的Activity
 20     private int fragmentContentId; // Activity中所要被替换的区域的id
 21 
 22     private int currentTab; // 当前Tab页面索引
 23 
 24     private OnRgsExtraCheckedChangedListener onRgsExtraCheckedChangedListener; // 用于让调用者在切换tab时候增加新的功能
 25 
 26     public FragmentTabAdapter(FragmentActivity fragmentActivity, List<Fragment> fragments, int fragmentContentId, RadioGroup rgs) {
 27         this.fragments = fragments;
 28         this.rgs = rgs;
 29         this.fragmentActivity = fragmentActivity;
 30         this.fragmentContentId = fragmentContentId;
 31 
 32         // 默认显示第一页
 33         FragmentTransaction ft = fragmentActivity.getSupportFragmentManager().beginTransaction();
 34         ft.add(fragmentContentId, fragments.get(0));
 35         ft.commit();
 36 
 37         rgs.setOnCheckedChangeListener(this);
 38 
 39 
 40     }
 41 
 42     @Override
 43     public void onCheckedChanged(RadioGroup radioGroup, int checkedId) {
 44         for(int i = 0; i < rgs.getChildCount(); i++){
 45             if(rgs.getChildAt(i).getId() == checkedId){
 46                 Fragment fragment = fragments.get(i);
 47                 FragmentTransaction ft = obtainFragmentTransaction(i);
 48 
 49                 getCurrentFragment().onPause(); // 暂停当前tab
 50 //                getCurrentFragment().onStop(); // 暂停当前tab
 51 
 52                 if(fragment.isAdded()){
 53 //                    fragment.onStart(); // 启动目标tab的onStart()
 54                     fragment.onResume(); // 启动目标tab的onResume()
 55                 }else{
 56                     ft.add(fragmentContentId, fragment);
 57                 }
 58                 showTab(i); // 显示目标tab
 59                 ft.commit();
 60 
 61                 // 如果设置了切换tab额外功能功能接口
 62                 if(null != onRgsExtraCheckedChangedListener){
 63                     onRgsExtraCheckedChangedListener.OnRgsExtraCheckedChanged(radioGroup, checkedId, i);
 64                 }
 65 
 66             }
 67         }
 68 
 69     }
 70 
 71     /**
 72      * 切换tab
 73      * @param idx
 74      */
 75     private void showTab(int idx){
 76         for(int i = 0; i < fragments.size(); i++){
 77             Fragment fragment = fragments.get(i);
 78             FragmentTransaction ft = obtainFragmentTransaction(idx);
 79 
 80             if(idx == i){
 81                 ft.show(fragment);
 82             }else{
 83                 ft.hide(fragment);
 84             }
 85             ft.commit();
 86         }
 87         currentTab = idx; // 更新目标tab为当前tab
 88     }
 89 
 90     /**
 91      * 获取一个带动画的FragmentTransaction
 92      * @param index
 93      * @return
 94      */
 95     private FragmentTransaction obtainFragmentTransaction(int index){
 96         FragmentTransaction ft = fragmentActivity.getSupportFragmentManager().beginTransaction();
 97         // 设置切换动画
 98         if(index > currentTab){
 99             ft.setCustomAnimations(R.anim.slide_left_in, R.anim.slide_left_out);
100         }else{
101             ft.setCustomAnimations(R.anim.slide_right_in, R.anim.slide_right_out);
102         }
103         return ft;
104     }
105 
106     public int getCurrentTab() {
107         return currentTab;
108     }
109 
110     public Fragment getCurrentFragment(){
111         return fragments.get(currentTab);
112     }
113 
114     public OnRgsExtraCheckedChangedListener getOnRgsExtraCheckedChangedListener() {
115         return onRgsExtraCheckedChangedListener;
116     }
117 
118     public void setOnRgsExtraCheckedChangedListener(OnRgsExtraCheckedChangedListener onRgsExtraCheckedChangedListener) {
119         this.onRgsExtraCheckedChangedListener = onRgsExtraCheckedChangedListener;
120     }
121 
122     /**
123      *  切换tab额外功能功能接口
124      */
125     static class OnRgsExtraCheckedChangedListener{
126         public void OnRgsExtraCheckedChanged(RadioGroup radioGroup, int checkedId, int index){
127 
128         }
129     }
130 
131 }
View Code

这里解决Fragment切换重新加载布局的办法,用的是把几个Fragment全部Add,然后根据要显示的哪个Fragment设置show或者hide

效果输出:

10-10 11:55:41.168: INFO/System.out(18368): AAAAAAAAAA____onAttach      // 第一次进入,显示TabA
10-10 11:55:41.168: INFO/System.out(18368): AAAAAAAAAA____onCreate
10-10 11:55:41.168: INFO/System.out(18368): AAAAAAAAAA____onCreateView
10-10 11:55:41.175: INFO/System.out(18368): AAAAAAAAAA____onActivityCreated
10-10 11:55:41.179: INFO/System.out(18368): AAAAAAAAAA____onStart
10-10 11:55:41.179: INFO/System.out(18368): AAAAAAAAAA____onResume
10-10 11:55:44.980: INFO/System.out(18368): AAAAAAAAAA____onPause      // 从TabA切换到TabB(TabA调用onPause)
10-10 11:55:44.980: INFO/System.out(18368): Extra---- 1 checked!!!
10-10 11:55:44.996: INFO/System.out(18368): BBBBBBBBBBB____onAttach
10-10 11:55:44.996: INFO/System.out(18368): BBBBBBBBBBB____onCreate
10-10 11:55:44.996: INFO/System.out(18368): BBBBBBBBBBB____onCreateView
10-10 11:55:45.004: INFO/System.out(18368): BBBBBBBBBBB____onActivityCreated
10-10 11:55:45.004: INFO/System.out(18368): BBBBBBBBBBB____onStart
10-10 11:55:45.004: INFO/System.out(18368): BBBBBBBBBBB____onResume
10-10 11:55:52.062: INFO/System.out(18368): BBBBBBBBBBB____onPause      // 从TabB切换到TabC(TabB调用onPause)
10-10 11:55:52.062: INFO/System.out(18368): Extra---- 2 checked!!!
10-10 11:55:52.082: INFO/System.out(18368): CCCCCCCCCC____onAttach
10-10 11:55:52.082: INFO/System.out(18368): CCCCCCCCCC____onCreate
10-10 11:55:52.086: INFO/System.out(18368): CCCCCCCCCC____onCreateView
10-10 11:55:52.090: INFO/System.out(18368): CCCCCCCCCC____onActivityCreated
10-10 11:55:52.090: INFO/System.out(18368): CCCCCCCCCC____onStart
10-10 11:55:52.090: INFO/System.out(18368): CCCCCCCCCC____onResume
10-10 11:56:06.535: INFO/System.out(18368): CCCCCCCCCC____onPause      // 从TabC切换到TabB(TabC调用onPause)
10-10 11:56:06.535: INFO/System.out(18368): BBBBBBBBBBB____onResume    // 从TabC切换到TabB(TabB调用onResume)
10-10 11:56:06.535: INFO/System.out(18368): Extra---- 1 checked!!!

 

好了,到此为止,我们已经用Fragment实现了类似TabHost的功能了,下面来看下各个Fragment之间的通信

现在的情况是TabAFm中有个EditText,TabBFm中有个Button,MainActivity中有个变量“hello”

要做的是,切换到TabA,输入“I'm TabA”,切换到B,点击Button后,Toast显示“hello I'm TabA”

MainActivity中没什么好说的,就一个hello变量:

public String hello = "hello ";

TabAFm在布局文件tab_a.xml中加个EditText,设置个id就可以了

TabBFm中:

 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     }
View Code
// 获得绑定的FragmentActivity
MainActivity activity = ((MainActivity)getActivity());

通过getActivity()即可得到Fragment所在的FragmentActivity

 

最终效果图:

demo下载地址:http://pan.baidu.com/s/1wxsIX

posted @ 2013-10-10 11:37  天天_byconan  阅读(91822)  评论(21编辑  收藏  举报