Android利用Fragment实现Tab选项卡效果

利用fragment实现tab选项卡效果： 

将radiogroup与fragment集合，实现tab选项卡效果，这里面最关键的几个文件： 

1.fragmenttabadapter类：

/**
 *@description: 
 *@author:nate robinson 
 *@since:2015-2-12
 */
public class fragmenttabadapter implements radiogroup.oncheckedchangelistener
{
 private list<fragment> fragments; // 一个tab页面对应一个fragment

 private radiogroup rgs; // 用于切换tab

 private activity activity; // 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

 public fragmenttabadapter(activity activity, list<fragment> fragments, int fragmentcontentid, radiogroup rgs)
 {
  this.fragments = fragments;
  this.rgs = rgs;
  this.activity = activity;
  this.fragmentcontentid = fragmentcontentid;

  // 默认显示第一页
  android.app.fragmenttransaction ft = activity.getfragmentmanager().begintransaction();
  ft.add(fragmentcontentid, fragments.get(0));
  ft.commit();

  rgs.setoncheckedchangelistener(this);

 }

 @override
 public void oncheckedchanged(radiogroup radiogroup, int checkedid)
 {
  for(int i = 0; i < rgs.getchildcount(); i++)
  {
   if(rgs.getchildat(i).getid() == (checkedid))
   {
    fragment fragment = fragments.get(i);
    fragmenttransaction ft = activity.getfragmentmanager().begintransaction();
    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(radiogroup, 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 = activity.getfragmentmanager().begintransaction();
   if(idx == i)
   {
    ft.show(fragment);
   }
   else
   {
    ft.hide(fragment);
   }
   ft.commit();
  }
  currenttab = idx; // 更新目标tab为当前tab
 }

 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
  */
 public interface onrgsextracheckedchangedlistener
 {
  void onrgsextracheckedchanged(radiogroup radiogroup, int checkedid, int index);
 }
} 

2.activity_main.xml布局文件：

<?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" />
  </radiogroup>
 </linearlayout>

</linearlayout>

3.mainactivity类：

/**
 *@description: 
 *@author:nate robinson 
 *@since:2015-2-12
 */
public class mainactivity extends activity
{
 private radiogroup rgs;

 private list<fragment> fragments = new arraylist<fragment>();

 private int index;

 private static boolean isexit = false;

 private static boolean hastask = false;

 private radiobutton button;

 private timer texit = new timer();

 private timertask task = new timertask()
 {
  @override
  public void run()
  {
   isexit = false;
   hastask = true;
  }
 };

 private fragmenttabadapter tabadapter;

 @override
 public void oncreate(bundle savedinstancestate)
 {
  super.oncreate(savedinstancestate);
  setcontentview(r.layout.activity_main);

  fragments.add(new fragmentone());
  fragments.add(new fragmenttwo());
  fragments.add(new fragmentthree());

  rgs = (radiogroup) findviewbyid(r.id.tabs_rg);

  button = (radiobutton) findviewbyid(r.id.tab_rb_a);

  tabadapter = new fragmenttabadapter(this, fragments, r.id.tab_content, rgs);
  tabadapter.setonrgsextracheckedchangedlistener(new fragmenttabadapter.onrgsextracheckedchangedlistener()
  {
   @override
   public void onrgsextracheckedchanged(radiogroup radiogroup, int checkedid, int index)
   {
    // 利用这个index可以实现，如果不是在主页，按第一遍让它先跳转到第一个fragment
    system.out.println("extra---- " + index + " checked!!! ");
    mainactivity.this.index = index;
   }
  });
 }

 @override
 public boolean onkeydown(int keycode, keyevent event)
 {
  if(keycode == keyevent.keycode_back)
  {
   if(index == 0)
   {
    if(isexit == false)
    {
     isexit = true;
     toast.maketext(mainactivity.this, "再按一次退出程序", toast.length_short).show();
     if(!hastask)
     {
      texit.schedule(task, 1000);
     }
    }
    else
    {
     finish();
     system.exit(0);
    }
   }
   else
   {
    // 如果不是在主页，按第一遍让它先跳转到第一个fragment
    // 利用上面的check方法会导致oncheckedchanged方法被执行多次
    // rgs.check(button.getid());
    button.setchecked(true);
   }

  }
  return false;
 }
}

为了能同时学习fragment生命周期，我在fragment每个生命周期方法中加入了log打印，一个有三个这样的fragment，我只贴出其中一个代码，其余和这个一样：

/**
 *@description: 
 *@author:nate robinson 
 *@since:2015-2-12
 */
public class fragmentone extends basefragment
{

 private view view;
 

 @override
 public void onattach(activity activity)
 {
  super.onattach(activity);
  log.d(tag, "1==>fragmentone=>onattach");
 }

 @override
 public void oncreate(bundle savedinstancestate)
 {
  log.d(tag, "2==>fragmentone==>oncreate");
  super.oncreate(savedinstancestate);
 }

 @override
 public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate)
 {
  log.d(tag, "3==>fragmentone==>oncreateview");
  view = inflater.inflate(r.layout.fragment1, container, false);
  textview tv = (textview) view.findviewbyid(r.id.tv);
  tv.settext("fragmentone");
  return view;
 }

 @override
 public void onactivitycreated(bundle savedinstancestate)
 {
  log.d(tag, "4==>fragmentone==>onactivitycreated");
  super.onactivitycreated(savedinstancestate);
 }

 @override
 public void onstart()
 {
  log.d(tag, "5==>fragmentone==>onstart");
  super.onstart();
 }

 @override
 public void onresume()
 {
  log.d(tag, "6==>fragmentone==>onresume");
  super.onresume();
 }

 @override
 public void onpause()
 {
  log.d(tag, "7==>fragmentone==>onpause");
  super.onpause();
 }

 @override
 public void onstop()
 {
  log.d(tag, "8==>fragmentone==>onstop");
  super.onstop();
 }

 @override
 public void ondestroyview()
 {
  log.d(tag, "9==>fragmentone==>ondestroyview");
  super.ondestroyview();
 }

 @override
 public void ondestroy()
 {
  log.d(tag, "10==>fragmentone==>ondestroy");
  super.ondestroy();
 }

 @override
 public void ondetach()
 {
  log.d(tag, "11==>fragmentone==>ondetach");
  super.ondetach();
 }

 @override
 public void onviewcreated(view view, bundle savedinstancestate)
 {

  log.d(tag, "fragmentone==>onviewcreated");
  super.onviewcreated(view, savedinstancestate);
 }
}

在编写过程中，我为了实现如果不是在主页，按第一遍让它先跳转到第一个fragment这个效果，一开始使用了rgs.check(button.getid());这个方法，结果发现，这样的话oncheckedchanged监听事件会执行两次，后来改为button.setchecked(true);这个方法之后，成功解决了这个问题。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。