浅谈Android选项卡（三）

上一节介绍了TabActivity的简单用法，但是现在的Api中已经不建议使用了，建议使用Fragment来替代以上的功能，下面介绍下使用Fragment和ViewPager的结合使用。

http://blog.csdn.net/xia215266092/article/details/9613985

TabActivity的文档。

This class was deprecated in API level 13.
New applications should use Fragments instead of this class; to continue to run on older devices, you can use the v4 support library which provides a version of the Fragment API that is compatible down to DONUT.

下面的示例是使用android-support-v4.jar，写的demo，这个demo也是api的demo。

<android.support.v4.app.FragmentTabHost    xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@android:id/tabhost"    android:layout_width="match_parent"    android:layout_height="match_parent">    <LinearLayout        android:orientation="vertical"        android:layout_width="match_parent"        android:layout_height="match_parent">        <TabWidget            android:id="@android:id/tabs"            android:orientation="horizontal"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_weight="0"/>        <FrameLayout            android:id="@android:id/tabcontent"            android:layout_width="0dp"            android:layout_height="0dp"            android:layout_weight="0"/>        <FrameLayout            android:id="@+id/realtabcontent"            android:layout_width="match_parent"            android:layout_height="0dp"            android:layout_weight="1"/>    </LinearLayout></android.support.v4.app.FragmentTabHost>

import com.example.android.supportv4.R;import android.os.Bundle;import android.support.v4.app.FragmentActivity;import android.support.v4.app.FragmentTabHost;/** * This demonstrates how you can implement switching between the tabs of a * TabHost through fragments, using FragmentTabHost. */public class FragmentTabs extends FragmentActivity {    private FragmentTabHost mTabHost;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.fragment_tabs);        mTabHost = (FragmentTabHost)findViewById(android.R.id.tabhost);        mTabHost.setup(this, getSupportFragmentManager(), R.id.realtabcontent);        mTabHost.addTab(mTabHost.newTabSpec("simple").setIndicator("Simple"),                FragmentStackSupport.CountingFragment.class, null);        mTabHost.addTab(mTabHost.newTabSpec("contacts").setIndicator("Contacts"),                LoaderCursorSupport.CursorLoaderListFragment.class, null);        mTabHost.addTab(mTabHost.newTabSpec("custom").setIndicator("Custom"),                LoaderCustomSupport.AppListFragment.class, null);        mTabHost.addTab(mTabHost.newTabSpec("throttle").setIndicator("Throttle"),                LoaderThrottleSupport.ThrottledLoaderListFragment.class, null);    }}

但是今天讲的不是这个，我讲Fragment是Android4.0以后的Fragment，android.app.Fragment，v4扩展包里面也有Fragment，但是是不一样的。

下面是用的是4.0以后的fragment，编译的版本和手机必须是4.0以后的，还是我这边引用的是android-support-v13.jar，这个jar，不是v4的。

package org.liushui.tabdemo.frag;import java.util.ArrayList;import java.util.List;import org.liushui.tabdemo.R;import android.app.ActionBar;import android.app.ActionBar.Tab;import android.app.Activity;import android.app.Fragment;import android.app.FragmentTransaction;import android.content.Context;import android.os.Bundle;import android.support.v13.app.FragmentStatePagerAdapter;import android.support.v4.view.ViewPager;public class MainFragmentActivity extends Activity {private ViewPager mViewPager;private TabsAdapter mTabsAdapter;protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.frag_main);mViewPager = (ViewPager) findViewById(R.id.pager);ActionBar bar = getActionBar();bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);bar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE | ActionBar.DISPLAY_SHOW_HOME);mTabsAdapter = new TabsAdapter(this, mViewPager);mTabsAdapter.addTab(bar.newTab().setText("电话"), AFragment.class, null);mTabsAdapter.addTab(bar.newTab().setText("短信"), BFragment.class, null);mTabsAdapter.addTab(bar.newTab().setText("拨号"), CFragment.class, null);}static class TabsAdapter extends FragmentStatePagerAdapter implements ActionBar.TabListener, ViewPager.OnPageChangeListener {private Context mContext;private ActionBar mActionBar;private ViewPager mViewPager;private List<TabInfo> mTabs = new ArrayList<TabInfo>();static class TabInfo {private Class<?> clss;private Bundle args;private Fragment fragment;TabInfo(Class<?> _class, Bundle _args) {clss = _class;args = _args;}}public TabsAdapter(Activity activity, ViewPager pager) {super(activity.getFragmentManager());mContext = activity;mActionBar = activity.getActionBar();mViewPager = pager;mViewPager.setAdapter(this);mViewPager.setOnPageChangeListener(this);mViewPager.setOffscreenPageLimit(3);}public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) {TabInfo info = new TabInfo(clss, args);tab.setTag(info);tab.setTabListener(this);mTabs.add(info);mActionBar.addTab(tab);}public int getCount() {return mTabs.size();}public int getItemPosition(Object object) {return POSITION_NONE;}public Fragment getItem(int position) {TabInfo info = mTabs.get(position);if (info.fragment == null) {info.fragment = Fragment.instantiate(mContext, info.clss.getName(), info.args);}return info.fragment;}public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}public void onPageSelected(int position) {mActionBar.setSelectedNavigationItem(position);}public void onPageScrollStateChanged(int state) {}public void onTabSelected(Tab tab, FragmentTransaction ft) {mViewPager.setCurrentItem(tab.getPosition(), true);}public void onTabUnselected(Tab tab, FragmentTransaction ft) {}public void onTabReselected(Tab tab, FragmentTransaction ft) {}}}

布局文件是很简单的，就是一个ViewPager就可以了，关于ViewPager，有点类似Android手机上面的Launcher，可以左右滑动。

<?xml version="1.0" encoding="utf-8"?><android.support.v4.view.ViewPager    xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@+id/pager"    android:layout_width="match_parent"    android:layout_height="match_parent"></android.support.v4.view.ViewPager>

上面代码中的子页面，AFragment，BFragment，CFragment，都是继承Fragment的，注意使用的android.app.Fragment.

package org.liushui.tabdemo.frag;import org.liushui.tabdemo.R;import android.app.Fragment;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;/** * Title: AFragment.java<br> * author:[e-mail] <br> * Date: 2013年7月29日<br> * Version:v1.0 */public class AFragment extends Fragment {public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {View view = inflater.inflate(R.layout.a, container, false);return view;}}

onCreateView这个方法，就是返回一个界面对象，在ViewPager中显示。