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:xiaqiulei@gmail.com <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。
