Android -- TabHost、Fragment、状态保存、通信
工程结构
TabAFm到TabEFm都是Fragment，并且每个Fragment对应一个布局文件。
TabAFm.java
package com.yydcdut.tabhoststudy; import android.app.Activity; import android.os.Bundle; import android.support.v4.app.Fragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; public class TabAFm extends Fragment { @Override public void onAttach(Activity activity) { super.onAttach(activity); System.out.println("AAAAAAAAAA____onAttach"); } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); System.out.println("AAAAAAAAAA____onCreate"); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { System.out.println("AAAAAAAAAA____onCreateView"); return inflater.inflate(R.layout.tab_a, container, false); } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); System.out.println("AAAAAAAAAA____onActivityCreated"); } @Override public void onStart() { super.onStart(); System.out.println("AAAAAAAAAA____onStart"); } @Override public void onResume() { super.onResume(); System.out.println("AAAAAAAAAA____onResume"); } @Override public void onPause() { super.onPause(); System.out.println("AAAAAAAAAA____onPause"); } @Override public void onStop() { super.onStop(); System.out.println("AAAAAAAAAA____onStop"); } @Override public void onDestroyView() { super.onDestroyView(); System.out.println("AAAAAAAAAA____onDestroyView"); } @Override public void onDestroy() { super.onDestroy(); System.out.println("AAAAAAAAAA____onDestroy"); } @Override public void onDetach() { super.onDetach(); System.out.println("AAAAAAAAAA____onDetach"); } }
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
MainActivity
package com.yydcdut.tabhoststudy; import java.util.ArrayList; import java.util.List; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentActivity; import android.support.v4.view.ViewPager; import android.widget.RadioGroup; public class MainActivity extends FragmentActivity { private RadioGroup rgs; public List<Fragment> fragments = new ArrayList<Fragment>(); public String hello = "hello "; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); fragments.add(new TabAFm()); fragments.add(new TabBFm()); fragments.add(new TabCFm()); fragments.add(new TabDFm()); fragments.add(new TabEFm()); rgs = (RadioGroup) findViewById(R.id.tabs_rg); FragmentTabAdapter2 tabAdapter = new FragmentTabAdapter2(this, fragments, R.id.tab_content, rgs); tabAdapter.setOnRgsExtraCheckedChangedListener(new FragmentTabAdapter2.OnRgsExtraCheckedChangedListener(){ @Override public void OnRgsExtraCheckedChanged(RadioGroup radioGroup, int checkedId, int index) { System.out.println("Extra---- " + index + " checked!!! "); } }); } }
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
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
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="@android:color/white" android:orientation="vertical" > <LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <FrameLayout android:id="@+id/tab_content" android:layout_width="fill_parent" android:layout_height="0dp" android:layout_weight="1.0" android:background="#77557799" /> <RadioGroup android:id="@+id/tabs_rg" android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center" android:orientation="horizontal" android:paddingBottom="7dp" android:paddingTop="7dp" > <RadioButton android:id="@+id/tab_rb_a" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1.0" android:background="@drawable/selector_tab" android:button="@null" android:checked="true" android:drawableTop="@drawable/tablatestalert" android:gravity="center" android:singleLine="true" android:text="Tab1" android:textColor="#000000" android:textSize="13sp" /> <RadioButton android:id="@+id/tab_rb_b" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1.0" android:background="@drawable/selector_tab" android:button="@null" android:drawableTop="@drawable/tabsearch" android:gravity="center" android:singleLine="true" android:text="Tab2" android:textColor="#000000" android:textSize="13sp" /> <RadioButton android:id="@+id/tab_rb_c" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1.0" android:background="@drawable/selector_tab" android:button="@null" android:drawableTop="@drawable/tabrecommd" android:gravity="center" android:singleLine="true" android:text="Tab3" android:textColor="#000000" android:textSize="13sp" /> <RadioButton android:id="@+id/tab_rb_d" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1.0" android:background="@drawable/selector_tab" android:button="@null" android:drawableTop="@drawable/tabconfigicon" android:gravity="center" android:singleLine="true" android:text="Tab4" android:textColor="#000000" android:textSize="13sp" /> <RadioButton android:id="@+id/tab_rb_e" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1.0" android:background="@drawable/selector_tab" android:button="@null" android:drawableTop="@drawable/tababoutus" android:gravity="center" android:singleLine="true" android:text="Tab5" android:textColor="#000000" android:textSize="13sp" /> </RadioGroup> </LinearLayout> </LinearLayout>
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
FragmentTabAdapter2 tabAdapter = new FragmentTabAdapter2(this, fragments, R.id.tab_content, rgs);
FragmentTabAdapter2
package com.yydcdut.tabhoststudy; import java.util.List; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentActivity; import android.support.v4.app.FragmentTransaction; import android.widget.RadioGroup; import android.widget.RadioGroup.OnCheckedChangeListener; public class FragmentTabAdapter2 { private List<Fragment> fragments; // 一个tab页面对应一个Fragment private RadioGroup rgs; // 用于切换tab private FragmentActivity fragmentActivity; // Fragment所属的Activity private int fragmentContentId; // Activity中所要被替换的区域的id private int currentTab; // 当前Tab页面索引 private OnRgsExtraCheckedChangedListener onRgsExtraCheckedChangedListener; // 用于让调用者在切换tab时候增加新的功能 /** * 构造函数 * * @param fragmentActivity * @param fragments * @param fragmentContentId * @param rgs */ public FragmentTabAdapter2(FragmentActivity fragmentActivity, List<Fragment> fragments, int fragmentContentId, RadioGroup rgs) { this.fragments = fragments; this.rgs = rgs; this.fragmentActivity = fragmentActivity; this.fragmentContentId = fragmentContentId; // 默认显示第一页 FragmentTransaction ft = fragmentActivity.getSupportFragmentManager() .beginTransaction(); ft.add(fragmentContentId, fragments.get(0)); ft.commit(); // 设置监听事件 MyCheckedChangeListener myCheckedChangeListener = new MyCheckedChangeListener(); rgs.setOnCheckedChangeListener(myCheckedChangeListener); } /** * 监听器内部类 * * @author sansung * */ class MyCheckedChangeListener implements OnCheckedChangeListener { @Override public void onCheckedChanged(RadioGroup group, int checkedId) { for (int i = 0; i < rgs.getChildCount(); i++) { if (rgs.getChildAt(i).getId() == checkedId) { Fragment fragment = fragments.get(i); FragmentTransaction ft = obtainFragmentTransaction(i); getCurrentFragment().onPause(); // 暂停当前tab // getCurrentFragment().onStop(); // 暂停当前tab if (fragment.isAdded()) { // fragment.onStart(); // 启动目标tab的onStart() fragment.onResume(); // 启动目标tab的onResume() } else { ft.add(fragmentContentId, fragment); } showTab(i); // 显示目标tab ft.commit(); // 如果设置了切换tab额外功能功能接口 if (null != onRgsExtraCheckedChangedListener) { onRgsExtraCheckedChangedListener .OnRgsExtraCheckedChanged(group, checkedId, i); } } } } } /** * 切换tab * * @param idx */ private void showTab(int idx) { for (int i = 0; i < fragments.size(); i++) { Fragment fragment = fragments.get(i); FragmentTransaction ft = obtainFragmentTransaction(idx); if (idx == i) { ft.show(fragment); } else { ft.hide(fragment); } ft.commit(); } currentTab = idx; // 更新目标tab为当前tab } /** * 获取一个带动画的FragmentTransaction * * @param index * @return */ private FragmentTransaction obtainFragmentTransaction(int index) { FragmentTransaction ft = fragmentActivity.getSupportFragmentManager() .beginTransaction(); // 设置切换动画 if (index > currentTab) { ft.setCustomAnimations(R.anim.slide_left_in, R.anim.slide_left_out); } else { ft.setCustomAnimations(R.anim.slide_right_in, R.anim.slide_right_out); } return ft; } public int getCurrentTab() { return currentTab; } public Fragment getCurrentFragment() { return fragments.get(currentTab); } public OnRgsExtraCheckedChangedListener getOnRgsExtraCheckedChangedListener() { return onRgsExtraCheckedChangedListener; } public void setOnRgsExtraCheckedChangedListener( OnRgsExtraCheckedChangedListener onRgsExtraCheckedChangedListener) { this.onRgsExtraCheckedChangedListener = onRgsExtraCheckedChangedListener; } /** * 切换tab额外功能功能接口 */ static class OnRgsExtraCheckedChangedListener { public void OnRgsExtraCheckedChanged(RadioGroup radioGroup, int checkedId, int index) { } } }
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
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：
@Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); System.out.println("BBBBBBBBBBB____onActivityCreated"); this.getView().findViewById(R.id.clickme).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { // 获得绑定的FragmentActivity MainActivity activity = ((MainActivity)getActivity()); // 获得TabAFm的控件 EditText editText = (EditText) activity.fragments.get(0).getView().findViewById(R.id.edit); Toast.makeText(activity, activity.hello + editText.getText(), Toast.LENGTH_SHORT).show(); } }); }
// 获得绑定的FragmentActivity MainActivity activity = ((MainActivity)getActivity());
通过getActivity()即可得到Fragment所在的FragmentActivity
本文转自我爱物联网博客园博客，原文链接：http://www.cnblogs.com/yydcdut/p/3889902.html，如需转载请自行联系原作者
